AxxSolder - JBC soldering controller - Page 1
Forum section: electronics / projects

author: AxxAxx
author_rank: Contributor
timestamp: October 18, 2023, 07:05:38 pm
content: Since it started a discussion about my project, AxxSolder in another forum thread:https://www.eevblog.com/forum/reviews/any-opinions-on-the-aixun-t3a/msg5115714/#msg5115714I thought it would be best to break out and create a separate thread here on EEVBlog Forum.So, AxxSolder is my attempt to create a soldering station (period)I want it to be simple and capable.With so many soldering iron projects out there it is difficult to come with something new, but with a background in Mechanical design and Mechatronics, I thought I could pull together something that doesn't only feels good to use but also performs well for a hobbyist or for me to have on my desk.Being used to working with the JBC range of irons, it is very difficult to go "back" or even choose something else (no offence Metcal and HAKKO users, you are also "nice"). Having the range of tips and irons that are available is truly amazing and gives you confidence over the competition.The goal is not that AxxSolder should support every soldering iron in the world, nor be the cheapest. But it should perform well, be open source and perform equally or better than competitors. I have for example a bunch of ideas I can see as improvement possibilities from the 930 Euro JBC DDE-2C soldering controller. The boot up time of ~6 seconds, the slow update rate on the screen, it is slow to change the temperature by pressing +/-, the temperature rolls over from 400 deg C to 250 deg C, annoying. It can be done better.So, let's keep this thread as a place for technical discussion and see what can be achieved. The last discussions were about the best way of grounding/earthing a soldering iron that is powered by either battery, floating or negative grounded SMPS..The project page can be found here:https://github.com/AxxAxx/AxxSolder

author: thm_w
author_rank: Super Contributor
timestamp: October 19, 2023, 10:08:27 pm
content: Incredible, good 3D print, very good documentation, high side driver, ESD protection, 1% dead time thermocouple measurement.I assume power limiting for T210 is in there somewhere? I didn't look closely the code.

author: AxxAxx
author_rank: Contributor
timestamp: October 20, 2023, 06:59:00 pm
content: Since there are many sources online on how the JBC cartridges are internally connected and they tend to not all agree I thought it would be good to clear this out once and for all, at least for C210 and C245.A good thing about designing your own soldering station is that you may end up with broken (overheated) cartridges from the early developmentThe cartridges I have are C210-029 and C245-945. I grinded away half of it and took some microscope pictures of the cross sections. I hope below images speak for themselves. Why there is a void in my C245-945 is another question, could it be from me overheating it? maybe..C210-029 belowC245-945 belowFrom external measurements it is not obvious how the internal configuration of the C245 looks.One can easily be tricked by measuring the generated voltage between BLUE and GREEN while heating the cartrigde tip by an external heat source. One will then read a voltage of close to zero volts and probably draw the conclusion that there can not be any thermocouple element between BLUE and GREEN..Upon closer inspection of my cross sections it is obvious that there are in fact 3 points where different components are joined together within the cartridge. And as we know, a thermocouple is just two dissimilar materials joined together, thus there are 3 thermocouple elements (shown as TC1, TC2 and TC3 in above image) within the tip. To prove that there are 3 thermocouple elements within the C245 tip I did some probing under a microscope while heating the cartridge tip with hot air to a temperature of aprox. 200-300 degree C. The voltage measurements were done with my FLUKE 87V in mV mode. I realize that even the junctions between my gold plated probes and the cartridge becomes a TC which should be compensated for, but for this measurement I neglect this effect.It can be seen that the 3 thermocouple elements are present. From the measured voltage one can aslo derive their corresponding relative seeback coefficient which shows that C1≈C2+C3.This in turn shows that the total seeback voltage one gets by measuring BLUE to GREEN is cancelled out by the three thermocouple elements in series thus yielding a total measured voltage of ~0 V.This was also presented by user DerDanielhttps://www.eevblog.com/forum/projects/jbc-handle-cartridge-data/msg3580774For the C210 cartridge it can be shown in similar way by probing the cross section while heating the tip that the tip contains two thermocouple elements. But as these are in series they do always appear to be only one TC from external measurements.

author: AxxAxx
author_rank: Contributor
timestamp: October 20, 2023, 07:20:04 pm
content: Quote from: thm_w on October 19, 2023, 10:08:27 pmThanks!Yes the software limits the power depending on which handle is detected:At the moment it is done in this code section:Code:/* If the handle_sense is high -> T210 handle is detected */if(sensor_values.handle_sense > 0.5){handle = T210;max_power_watt = 60; //60WKp = 20;Ki = 60;Kd = 0.5;}/* If the handle_sense is low -> T245 Handle */else{handle = T245;max_power_watt = 120; //120WKp = 30;Ki = 60;Kd = 1;}PID_SetTunings(&TPID, Kp, Ki, Kd); // Update PID parameters based on handle typeOn the ESD protection topic I think it could be done better, there is an active "issue" on the github page, meaning I'll probably make an update on that when I get time.

author: thm_w
author_rank: Super Contributor
timestamp: October 20, 2023, 09:15:48 pm
content: Yeah 60W is around what the clone stations seem to use. I don't know what JBC themselves use, unless you had measured that to confirm or got that number from somewhere else.Interesting to see the construction difference between the 210 and 245, and the void or blowout.. whatever that is. I wonder if thats filler material at the end.I don't think anyone has posted a 245 clone tip cutaway yet, just some where the tip had completely fell off, they might have huge voids as well.

author: c0d3z3r0
author_rank: Regular Contributor
timestamp: October 22, 2023, 11:05:00 am
content: Picking up the dicsussion regarding proper earthing of the AxxSoldere here again:Quote from: drksy on October 19, 2023, 01:33:55 amAfter some research I too believe that using an isolated DC/DC converter for the MCU side seems to be the best option. However, all the measurement and detection needs galvanic isolation as well, so you don't introduce that ground connection again:- both temperature sensing and current sensing need to be done with an isolated op-amp- some I2C isolated temperature sensing IC?- e.g. TI AMC1301 (or the cheaper AMC1101?) or Renesas RV1S9353A for current, but both are expensive. Maybe use a current sensing IC like ACS730?- stand sense through optocoupler- heater control through optocoupler- handle sense (id pin) through1) optocoupler if only checking for T245 vs. T210 or2) through a) isolated op-amp or b) linear optocoupler as a future option to support other handle types (probably not the plan anyways, is it?)So, the AxxSolder could then have a 3 pin supply connector VCC,GND,EARTH and it's up to the user what supply to use:- Toroidal transformer, rectified: connect VCC, GND + optional EARTH- Isolated SMPS (SELV / non-earthed) + optional EARTH- Isolated SMPS (PELV / earthed secondary) + optional EARTH (or just bridge GND/EARTH if you're 100% sure you have a PELV, not SELV supply)Another thing to note: without coupling primary and secondary side of the DC/DC converter, it will float (at the potential of the primary side, right?). I'm unsure if this creates any new problems.

author: drksy
author_rank: Regular Contributor
timestamp: October 23, 2023, 01:51:20 am
content: That's not quite what I meant. I wanted the SMPS ouput to be floating, and then only ground the 5V supply for the controller, so that the heater return current isn't connected to earth:This way, the opamps and all the electronics are referenced to mains earth which makes temperature sensing or stand sensing hassle free. You just need an optocoupler to drive the mosfet for the heater.

author: c0d3z3r0
author_rank: Regular Contributor
timestamp: October 23, 2023, 07:14:15 pm
content: Well, yes, but that would only make it work with a floating SMPS, not with a grounded one. My extension of your idea make it work with *any* SMPS.Also, I'm unsure if your setup with floating SMPS would be compliant with regulations in various regions (e.g. Germany, I doubt it).

author: drksy
author_rank: Regular Contributor
timestamp: October 24, 2023, 12:32:20 am
content: Quote from: c0d3z3r0 on October 23, 2023, 07:14:15 pmTrue, at the cost of adding significant complexity.Quote from: c0d3z3r0 on October 23, 2023, 07:14:15 pmThe heater power supply could be capacitively coupled to earth, like for example inRPS-200-24. Then that cap will also be across the thermocouple. Would that cause problems? Or could just be a transformer-rectifier-capacitor combo or batteries. I've seen many laptop power supplies or generic brick supplies for printer or such that have no earth connection anywhere.In the Meanwell LRS lineup, the output is floating, yet Y-rated filter caps are used on the primary side to ground. For example seeLRS-200I assume the ground symbol with circle lableled "FG" stands for frame ground, meaning it's the metal chassis. And if that's bolted to earth, then the mains input has caps to earth, presumably for filtering/emi reasons. However, theoutputis not anywhere tied to earth, so I don't think that's strictly a safety requirement. I've modified my diagram to make this more clear.

author: drksy
author_rank: Regular Contributor
timestamp: October 24, 2023, 03:39:57 am
content: Another suggestion to make AxxSolder even more accessible to the DIY community. I'm thinking what if someone wants to use a different display like the Nextion or even a 16x2 that they already have laying around, so having an I2C and/or SPI header on the PCB would be super useful. Having looked at your code, one would have to just modify `update_OLED` in main.c.

author: AxxAxx
author_rank: Contributor
timestamp: October 24, 2023, 06:34:28 am
content: Quote from: thm_w on October 20, 2023, 09:15:48 pmIt is indeed not so clear what power should be used for different cartridges, 60W/120W comes from various sources online and my own experience.I did however some more research in the topic and found from JBC:- CDN Station (C115 Cartridges) Peak power (Tool)25Whttps://www.jbctools.com/cdn-high-precision-soldering-station-product-2274.html- CDS Station (C210 Cartridges) Peak power (Tool)40Whttps://www.jbctools.com/cds-precision-soldering-station-product-1580.html- CDB Station (C245 Cartridges) Peak power (Tool)130Whttps://www.jbctools.com/cdb-soldering-station-product-1605.html- CP Station (AM120 tweezer=> two C210 cartridges) Peak power (Tool)80Whttps://www.jbctools.com/cp-precision-rework-station-product-1618.htmlSo if this is correct I could probably bump up the max power of C245 cartridges a bit from the current max power of 120W for C245 cartridges..Quote from: thm_w on October 20, 2023, 09:15:48 pmThe material you can see next to the void in the image is just a thin section of cupper, it could be "peeled away" and the void is also under it.

author: AxxAxx
author_rank: Contributor
timestamp: October 24, 2023, 09:07:38 am
content: Quote from: drksy on October 24, 2023, 12:32:20 amIt seems like c0d3z3r0's idea above would be a robust way to handle all different power solutions. To a cost/complexity indeed.For the heater control there are also Optically Isolated Gate Drivers designed for this purpose that one could consider.I think if the selection of power supply should be up to the user the grounding should work on whichever SMPS is used. It is not always clear for the user if your SMPS is floating or grounded...Quote from: c0d3z3r0 on October 22, 2023, 11:05:00 amI have also in my mind that it would be nice to be able to drive JBC tweezers. Then you need a second Sense pin to detect tweezers. (And a second heater/temperature sense circuit)It is always nice to add features but sometimes simplicity is king. Don't really know where that limit is for AxxSolder yet though..

author: AxxAxx
author_rank: Contributor
timestamp: October 24, 2023, 09:23:14 am
content: Quote from: drksy on October 24, 2023, 03:39:57 amGood idea!Adding a I2C header is simple, and SPI is already there.Then it could be up to anyone that want another display to branch out and crerate a driver for that particular display.Adding a I2C header also makes AxxSolder future-proof in case the selected OLED should go out of stock.The current status is that I have added some USB functionality. I want a programming interface over USB so that you do not need to have a SWD programmer to flash sofware onto AxxSolder. Luckily STM32G431 has native support for USB botloader and this should be easily implemented. I have also added a USB-C - PD negotiation circuit (STUSB4500https://www.st.com/en/interfaces-and-transceivers/stusb4500.html) with communication via I2C to the MCU. I'm not sure if this is a good idea but I had the circuit design ready from another project and I'll give it a try. I mean 100W is quite respectful and I think that 100W capable USB-C supplies will be more and more common in the future.The PCBs are ordered an I'll go on a 4 week vacation as of tomorrow. When I get back and have tested the USB solutions I think the grounding questions are next in line

author: miket6000
author_rank: Contributor
timestamp: October 24, 2023, 05:47:17 pm
content: Very nice project, well done.Just a word of caution about using the BAT54s as ESD protection, specifically on the handle. The leakage current on Schottky diodes is huge, at 25°C and 3V3 it's nominally 50nA and can be up to 10x worse, as it gets hotter it gets worse again. This leakage current will flow through your 470k resistor and can create large voltage offsets affecting the temperature measurement accuracy.I'd recommend using a low leakage ESD diode instead, something like a MAX14541 has a maximum leakage of 1nA (typical is less than 10pA). There are certainly many other options as well.Cheers

author: drksy
author_rank: Regular Contributor
timestamp: October 25, 2023, 02:29:39 am
content: Quote from: AxxAxx on October 24, 2023, 09:07:38 amThat's always the challenge. If isolation can be done elegantly for grounded heater supplies, I'm all for it. But it sounded like it requires obscure isolated opamps and dozens of added components and surrounding passives. I hope you can figure out a good solution, thought I don't think it's confusing or too much to just ask users to avoid supplies whose negatives are shorted to mains earth, as this is the case with majority of power supplies.Really like the look of that new fuse holder though. That car fuse had to go for sure. I wonder if you can merge the two USB ports into one? Can one port provide power delivery as well as be used to upgrade the firmware? That vertical micro-usb looks like an eye-sore. Maybe a USB switch chip with a select jumper?USB3740Bcould be a candidate. Cheap and readily available.

author: Pooya
author_rank: Contributor
timestamp: October 25, 2023, 10:56:06 am
content: This is my personal opinion, The box has to be redesigned. The power port does not have any lock that can stand completely in the enclosure and must be fixed with some glue. All screws holes and some walls are so thin and can break so easily, you can use heatset insert for screws, The Encolsure_JBC-AD-SF does not have bottom plate, XT60e-m should be a good option for power port.

author: AxxAxx
author_rank: Contributor
timestamp: October 25, 2023, 11:56:19 am
content: Quote from: drksy on October 25, 2023, 02:29:39 amYes it doesn't seem optimal to have two separate USB Ports. The design above will work as my test board and have Both USBs connected to the MCU. On this board there are solder jumpers to turn on/off USB-C data.. It's in a development branch so noone except me should make this PCB version.The reason I did not go with only the USB-C is that I do not know how the firmware upload will work with different USB supplies. If you have a proper USB-C PD capable computer then it should be fine. But if you only have a 5V capable USB-C cable and want to flash new software, as the USB-C is connected to VDD to power everything I'm not sure how the DC/DC converter will handle that as it is outside the specs of min in voltage. By having a separate micro USB I can always know I get 5V from there and feed that through a diode and to the 5V bus on the board.I am also not sure how the USB-C PD circuit will handle the case when you have 24V from a separate supply and plug in a USB-C cable.. Have to investigate that,which I can do on this board.It is also a bit unconvinient to program the station version if the usb is horizontal on the board.. I think a redesign of both enclosures so that you have a USB-C port available for programming and power would be best.

author: AxxAxx
author_rank: Contributor
timestamp: October 25, 2023, 12:02:58 pm
content: Quote from: Pooya on October 25, 2023, 10:56:06 amYes totally agree with you. If AxxSolder turns out to be popular and more people are starting to make one a redesign should be done. The selection of PP45 Connector comes from that I have used a brunch in other projects and I have batteries with them. It has been on my list to redesign the mounting of that connector. A panel mounted XT60 could be an option. However what I like about PP45 is that they snap together with a positive feedback. I personally prefer a PP45, I could design a panel mount for that. There could maybe be a enclosure version for Xt60e too. At work I would probably use something from Molex, TE or similar industry brand but thoese crimping terminal are not nice if you dont have the correct crimp tools.Regarding the thin sections, I assume you mean around the display, there they are very thin in order to fit the display flat to the top surface. I printed my cases on a Markforged printer with their Onyx filament. I assume a more hobby-level printers will struggle more with some features.. I have create an Issue on github for this. Feel free to comment on that issue if you have more ideas regarding this topic. It will be done after my 4 week vacation.

author: Pooya
author_rank: Contributor
timestamp: October 25, 2023, 07:12:57 pm
content: I did some changes to portable version with thicker face plate, XT60, heatset insert and rocker switch, removed the 4 screw hole (OLED mount) from faceplate and removed the metal piece for sleep mode because I want to attach it to my chinese stand, It is compatible with JBC handle with input and output, useless for me! You can attach the pcb to body from inside. Later I will work on the other one.

author: Pooya
author_rank: Contributor
timestamp: October 26, 2023, 01:21:56 am
content: Modified - Final

author: Warhawk
author_rank: Frequent Contributor
timestamp: October 26, 2023, 07:03:55 am
content: Don't you have an extra PCB?I am too in Germany.

author: Pooya
author_rank: Contributor
timestamp: October 26, 2023, 11:58:49 am
content: I have, the domestic shipping cost is between 8 to 10 euro, I paid total 6 euro include shipping VAT everything for 5 pcbs from JLCpcb, If is worth it then I can send.

author: AxxAxx
author_rank: Contributor
timestamp: October 28, 2023, 04:21:48 am
content: Quote from: AxxAxx on October 25, 2023, 11:56:19 amI found the answer to my own question about what happens when the USB PD countroller can't get the asked for voltage or current, in the datasheet for CYPD3177:SAFE_PWR_EN Gate DriverThe EZ-PD BCR device has a SAFE_PWR_EN gate driver that can be used to drive an alternate load switch/FET. It is enabled whenever the EZ-PD BCR device is unable to negotiate the requested power contract. In such a scenario, the EZ-PD BCR device negotiates a 5-V/900-mA contract which can be delivered through the SAFE_PWR_EN FET to an alternate power rail in the system. This allows the system to operate in a limited mode when the requested power is unavailable through the USB Type-C port.Perfect! Thats exactly what I needed. This controller is also cheap, around 2 Euro.

author: drksy
author_rank: Regular Contributor
timestamp: October 28, 2023, 01:25:04 pm
content: That's a brilliant solution! I was just thinking about a similar thing to switch the 5V with a mosfet if you detect a PD failure over i2c. And since negotiating power delivery over USB-C apparently doesn't involve the data lines D+ and D-, it makes it even simpler. Nice.

author: c0d3z3r0
author_rank: Regular Contributor
timestamp: October 29, 2023, 02:01:55 pm
content: @drsky Regarding regulations, the fact that gloating supplies are availavle doesn't mean that they are allowed in any use case. (Not all use cases allow choosing any one of SELV, PELV, FELV). However, in this specific one (solder station) both SELV, PELV seem to be ok.Btw. Having a SELV SMPS and then grounding the secondary of the DC/DC converter still makes the whole construct PELV, even though the grounding is done bc of functional, not safety reasons.I just had another random idea, that needs further evaluation, though: instead of all that isolation complexity from my post, why not have a second smaller uC, that only does measurements and heating control in the 24V circuit, communicating over isolated I2C with the main uC.@AxxAxx why not use the native USBPD controller of the STM32G?Also, I don't think any MOSFET for power switching is required but just two diodes separating power inputs (main power input, USB-C). This way both inputs just go straight to the 5V DC/DC regulator. (4.5V minimum, so ok with the default 5V)

author: eliocor
author_rank: Unknown
timestamp: October 29, 2023, 02:28:48 pm
content: Nice project, but I will be more interested if it will support even the T115 handle (I work only with SMD components): I own a T3B solder station, but as you can see:https://www.eevblog.com/forum/reviews/aixun-t3b-strange-behavior-(must-invert-liveneutral)/msg5135604/#msg5135604I'm not so enthusiast of it*!If needed I can sponsor AxxAxx with a T115 handle + tips...*) just to be fair, the station works flawlessly except for the strange behavior

author: c0d3z3r0
author_rank: Regular Contributor
timestamp: October 29, 2023, 03:56:40 pm
content: T115 is 12V, while T245/T210 use 24V. It should be possible to adapt the code (heating curve, detection (probably same connection as T210)) and use it with 12V input.

author: c0d3z3r0
author_rank: Regular Contributor
timestamp: October 29, 2023, 04:00:23 pm
content: Quote from: drksy on October 25, 2023, 02:29:39 amMajority, u sure? Maybe true for cheapo supplies for consumer-grade laptops. Higher-quality Laptop supplies (USB-C and regular), I don't think this is true. Dell, Lenovo, Apple (with cable attached, not the short euro plug), ..., they're all earthed on the secondary.EDIT: Oh wait, did you mean that ("this is the case")?Oh well, and I see many Github issues with bricked devices incoming because of wrong choice of the supply

author: eliocor
author_rank: Unknown
timestamp: October 29, 2023, 04:30:20 pm
content: It would be wonderful: a very small T115 controller powered by an USB-C (TD) power supply*!Just something which can be carried everywhere for any electronic emergency*) unluckily, if I remember correctly, their maximum reach is 100W/20V (not 24V)

author: c0d3z3r0
author_rank: Regular Contributor
timestamp: October 29, 2023, 04:33:26 pm
content: Yeah, 20V is max. but you can still run T245 with that, just with limited power. That's probably still way better than any regular soldering iron

author: drksy
author_rank: Regular Contributor
timestamp: October 29, 2023, 11:03:56 pm
content: Quote from: c0d3z3r0 on October 29, 2023, 02:01:55 pmRight, in some applications like a PC power supply, PELV would be required, but not in this one. Let's say somebody is building this soldering iron controller for the first time. Which is more hassle, picking a power supply whose negative is not connected to earth? Or buying/soldering/programming a whole second microcontroller, and paying for and dealing with isolated i2c, and then have to manage two separate code projects which have to be uploaded separately, through what, two separate ports? I'm sorry, but this is just a mess!But what if you don't care about isolation and the error current that's passing from heater positive through the thermocouple, through earth back to negative. AxxSolder as it is right now turns off the heater, waits a little bit for the thermocouple to stabilize, then takes a measurement. Would this break if we are dealing with a PELV and a earth-grounded tip? Maybe all that's needed for ESD safety is just an added connection from the outer shell and the board ground to earth, and leave everything else as it is. What am I missing?

author: c0d3z3r0
author_rank: Regular Contributor
timestamp: October 30, 2023, 06:42:32 am
content: Well, having a PELV supply will not only lead to a small error current to earth but to a short to ground (ok, nearly, it's a few ohms)

author: Warhawk
author_rank: Frequent Contributor
timestamp: October 30, 2023, 10:21:20 am
content: Quote from: Pooya on October 26, 2023, 11:58:49 amWell, you have quite expensive shipping there. Here in Munich an envelope with the PCB is 90 cents or coLet me study the project more in detail. I want to check how mature this is.

author: drksy
author_rank: Regular Contributor
timestamp: October 31, 2023, 03:49:44 am
content: Quote from: c0d3z3r0 on October 30, 2023, 06:42:32 amOkay I see problem now. In the AxxSolder, heater current starts from red and returns to blue, so with PELV, blue will be permanently tied to earth. But if green is also connected to earth, when applying to power to red, the supply will basically be shorted through the termocouple. Bad idea! I need to get more sleep.The combination of PELV and grounded tip always introduces a problematic current path. If you apply 24V to blue and return to red, red will be earth and thermocouple will be permanently shorted. And if you apply 24V to red and return to blue, the supply will be right across the thermocouple because the outer shell and supply negative are both earth. How can this even be resolved with isolation? The earth connection in the heater supply secondary conflicts with the added requirement that the outer shell should be earth.The only way this can work is to do a similar thing Aixun does: start the heater current from blue and return to the outer shell (green) through the thermocouple. The supply negative would be permanently earthed, and so is the outer shell.

author: c0d3z3r0
author_rank: Regular Contributor
timestamp: October 31, 2023, 07:50:46 am
content: Well, then you create the problems the Aixun has for the Axxsolder. Thus, either your picture with SELV or my extension with various isolation measures helps. In your picture no current can flow to earth/GND of the first stage secondary side because the SELV secondary has no potential to mains earth.

author: drksy
author_rank: Regular Contributor
timestamp: October 31, 2023, 08:16:32 am
content: @c0d3z3r0 Imagine you have a PELV supply and want to build a C245 controller that has a grounded tip. What I'm saying is that's not even possible to do, except the way Aixun does it - which of course as you pointed out comes with all the limitations and problems of Aixun. It's not ideal. This is why I think using an PELV heater supply in the first place is just a bad idea.

author: c0d3z3r0
author_rank: Regular Contributor
timestamp: October 31, 2023, 11:53:48 am
content: Sorry, I misread your PELV as SELV. Hm, I need to think about the PELV construct againEDIT: @drsky You are right. This edited picture helps understanding the problem :-) Btw. you had +24V/GND swapped. (I didn't fix the TC input here)So, one can't have a PELV supply and grounded tip. Earthing is only possible by using a) battery power b) SELV supply c) toroidal transformer. If someone wants full flexibility, earthing is not possible.Ok, next idea:- instead of the TPS54302 converter use a isolated DC/DC converter module (will work regardless of supply type)OR:dual pcb design, so either option can be populated based on user choice- control heater through optocoupler or isolated mosfet driver -no idea how one would combine optocoupler + mosfet driver...Maybe replace LTC4440 with HCPL-3120?- provide a earth connector on the board + add earthing circuit like JBC does (can be left unpopulated if earthing not wanted by user)- add a big note to document a) the options and b) the incompatibility of tip earthing with PELV / grounded supplies

author: Pooya
author_rank: Contributor
timestamp: November 01, 2023, 12:09:37 am
content: Yaaaay it's alive, for yours order stencil that was pain in the ass, it was so difficult to solder

author: Pooya
author_rank: Contributor
timestamp: November 01, 2023, 02:22:31 am
content: with box

author: drksy
author_rank: Regular Contributor
timestamp: November 01, 2023, 07:23:35 am
content: @Pooya wow! Nice! Really cool red enclosure you made there. How well does it work? Have you tested it?Quote from: c0d3z3r0 on October 31, 2023, 11:53:48 amYeah I goofed that up. In the original JBC it's supposed to start from red and return to blue.Quote from: c0d3z3r0 on October 31, 2023, 11:53:48 amThis is one of those times you can "come agutsa" as Dave likes to sayImagine if you try to probe the heater waveform with your earth referenced oscilloscope, clip the alligator to negative, probe the positive, turn it on, and BANG!Really gotta be careful with this earth connection to not short something.Quote from: c0d3z3r0 on October 31, 2023, 11:53:48 amYeah I goofed that up. In the original JBC it's supposed to start from red and return to blue.Quote from: c0d3z3r0 on October 31, 2023, 11:53:48 amMaybe even another screw terminal for the 5V if someone wants just use a wall wart or something. It could also be a push-pull transformer driver like the LT3439 or the SN6507. Both of these could work with surface mount transformer which isn't going to be too much bigger than a typical high power inductor. But a power module is the simplest and most compact way to go imo.As for isolated mosfet drivers, you could basically keep the LTC4440 + NMOS the way it is and just isolate the input to the gate driver with a jellybean PC817 + pulldown resistor.

author: Pooya
author_rank: Contributor
timestamp: November 01, 2023, 10:25:54 am
content: I don't know I did something wrong or it should be like that! or it has to be fixed from the firmware, when the handle is not connected,should say that (No Tool) or something like that, even the temperature should not be shown. but as you can see in the photo it shows even the handle type while nothing connected to the board.

author: c0d3z3r0
author_rank: Regular Contributor
timestamp: November 01, 2023, 10:55:03 am
content: Quote from: drksy on November 01, 2023, 07:23:35 amNot sure what exactly you are referring to. What will break? The scope? Isn't that only a problem when trying to measure the high side? I mean, my scope is still fine after measuring stuff on the Grounded Aixun.Quote from: drksy on November 01, 2023, 07:23:35 am+1Quote from: drksy on November 01, 2023, 07:23:35 amYeah, there are various possibilities. The cheapest module I could find on a quick check was ~8€, the SN6507 is ~3€ without jelly bean parts, the LKT3439 alone costs ~10€Using the module should be roughly equal costs, but saves soldering effort and maybe a bit space on the pcb.Quote from: drksy on November 01, 2023, 07:23:35 amI don't think that works because the MOSFET and gate driver need to have common GND and the MOSFET needs GND on the 24V rail as well. Since that currently used gate driver can't be driven with 24V VCC, you have the common ground problem again. Am I missing something?Ohhh, I just realized that *maybe* there is another problem. I might be wrong, but to me it looks like the tc (and current) measurement as it is done currently, won't work in the SELV szenario because it breaks isolation as well... Isn't the OpAmp comparing the two voltages +/-, that are both referenced to GND? So we have + -> GND (RED -> BLUE), - -> GND (GREEN -> BLUE), out -> GND with common GND again...

author: c0d3z3r0
author_rank: Regular Contributor
timestamp: November 01, 2023, 06:43:40 pm
content: Quote from: miket6000 on October 24, 2023, 05:47:17 pmWhy would the diodes get hot at all? They are not inside the handle but on the control board.

author: drksy
author_rank: Regular Contributor
timestamp: November 02, 2023, 02:02:23 am
content: @c0d3z3r0 I meant in the situation where you useSELV in the picture you made with grounded tip but without the earth connection on heater negative, and then you try to measure the heater waveform with an earth-referenced scope, which then turns thatSELV intoPELV via the alligator clip!Quote from: c0d3z3r0 link=topic=397518.msg5145879#msg5145879You're right, it might need a 7805 just for the VCC pin of the gate driver. I imagine the gate drive IC, the mosfet, and optocoupler transistor would all live in the 24V domain and use the heater ground for their return paths. The controller PCB pretends they don't even exist, all the main PCB sees is an LED.Quote from: c0d3z3r0 link=topic=397518.msg5145879#msg5145879I'm not understanding this bit. Maybe you can draw it?Quote from: c0d3z3r0 on November 01, 2023, 06:43:40 pmI suppose if some component on the pcb pisses away heat, that would heat up the whole board, and because these are smd diodes, they all start heating up. I do agree that the BAT54S's should be replaced with a low-leakage ESD-specific diode.I want tot also point out the in the reverse engineering of CD-2BC station, the heater AC winding negative and board ground are both labeled GND. I still don't fully understand what's the best way to ground this station with a DC supply. Let's wait to see what solution Mr Axx comes up with.

author: drksy
author_rank: Regular Contributor
timestamp: November 02, 2023, 02:04:25 am
content: Quote from: Pooya on November 01, 2023, 10:25:54 amHave you connected the inputs for Handle_sense and Stand_sense? But yeah, it really shouldn't output garbage when nothing is connected. I assume there are plenty of improvements to make to the software.

author: Pooya
author_rank: Contributor
timestamp: November 02, 2023, 04:31:49 pm
content: Yes needs some improvements. I didn't test yet, waiting for 6 pin handle socket. Later I will write the issues here.

author: c0d3z3r0
author_rank: Regular Contributor
timestamp: November 03, 2023, 09:39:29 am
content: Quote from: drksy on November 02, 2023, 02:02:23 amYes, that's what I meant. Not sure if a 7805 is the best option, though. (heat, but might be not relevant due to little current)Quote from: drksy on November 02, 2023, 02:02:23 amWell, voltages is all about references, right? The main question is: does the OpAmp measure a) voltages at +/- against GND or b) voltage at + with reference to - and then compare them?If a) then this won't work in an isolated GND szenario because there is no connection between OpAmps GND and the TC GND.I believe it is a) and that is why isolated OpAmps exist...EDIT: it seems to be possible to amplify an isolated signal as well. See page 3:https://www.analog.com/media/en/analog-dialogue/volume-44/number-4/articles/measuring-temp-using-thermocouples.pdfQuote from: drksy on November 02, 2023, 02:02:23 amYeah, I would do that, too. However, JBC also used BAT54sAnother thing I noticed in the CB-2BC schematics: JBC measures leakage current to EARTH o.O Maybe because it influences TC measurement as well...

author: Warhawk
author_rank: Frequent Contributor
timestamp: November 04, 2023, 08:51:47 am
content: As a guy from the semi industry, I often see engineers using schottky diodes such as BAT54 for protection. This is a bad design practice. They really leak current that varies with temperature. This leakage also differs from manufacturer to manufacturer. I've seen real pre-production designs failing specs because of it (analog front-ends and opamps).just my 2 cents

author: sorin
author_rank: Frequent Contributor
timestamp: November 04, 2023, 06:44:02 pm
content: Quote from: Warhawk on November 04, 2023, 08:51:47 amWhat do you suggest as a replacement?

author: c0d3z3r0
author_rank: Regular Contributor
timestamp: November 05, 2023, 02:07:07 pm
content: I took another look at suitable isolated DC/DC modules. There are even cheaper variants than I found initially (~8€).Assuming ~300mA output will be sufficient (probably even lower is fine), you can get modules starting at ~2.50€ (Mouser , didn't check DigiKey) e.g. IEB0124S3V3, IEB0124S05, PDSE1-S24-S3-S, PDSE1-S24-S5-S, CRE1S2405SC (SMD option!), ...Most datasheets recommend a EMC/EMI circuit (Y cap, input/output filter caps, inductor). Maybe one might just waive it in a private project, but it's probably better to do it "right", since it's just a few components more and still less components than using SN6507.https://mou.sr/3QL9cZI

author: c0d3z3r0
author_rank: Regular Contributor
timestamp: November 05, 2023, 02:32:33 pm
content: Quote from: sorin on November 04, 2023, 06:44:02 pmUsually, one would choose diodes with lower forward voltage than the internal protection diodes, so they start conducting before the internal ones. Unfortunately, TI doesn't tell us what diodes are used in the OPA2333, but only say there are diodes :/The main question for me is: how much reverse current is too much in this specific case? I still don't believe the diodes get that hot on that board, at least not >30 - 40 °C and e.g. for Vishay BAT54s leak current is ~1-2 uA at 50°C.@Warhawk can you share more details from your experience and a suitable alternative?

author: drksy
author_rank: Regular Contributor
timestamp: November 05, 2023, 09:55:54 pm
content: Quote from: c0d3z3r0 on November 03, 2023, 09:39:29 amI have another idea. What if we don't isolate the 5V supply and don't make the controller board earth-referenced, the heater ground would be the same as controller ground, and to measure tip temperature, we use an opamp as a differential amplifier to measure the voltage difference between red and green. What are the downsides?

author: miket6000
author_rank: Contributor
timestamp: November 06, 2023, 01:38:35 am
content: My comment about the diodes getting hot is a somewhat generic one about the issues with Schottky diodes in general. That said you have a power switching controller in a plastic box with no vents, I wouldn't be surprised if the ambient was above 40°C.The biggest issue in this case is that the leakage current will show up as a voltage on the thermocouple input. I'm not sure what thermocouples are in the handles in the JBC irons, but it's likely in the order of 40uV/°C and the input impedance is dominated by R21 and R22 which are 470k, so a small imbalance in leakage current could easily be enough of an issue to make the iron unusable.

author: c0d3z3r0
author_rank: Regular Contributor
timestamp: November 06, 2023, 08:48:44 am
content: Quote from: miket6000 on November 06, 2023, 01:38:35 amThank you! JBC uses a custom theromcouple with ~40 uV/°C:https://www.eevblog.com/forum/beginners/jbc-t245c245-thermocouple-thermal-coefficient/

author: c0d3z3r0
author_rank: Regular Contributor
timestamp: November 06, 2023, 08:53:46 am
content: Quote from: drksy on November 05, 2023, 09:55:54 pmThat's basically what Aixun did, just with a differential amplifier without GND-reference and with SELV instead of PELV. Indeed, that might solve the problems of the T3A already.Hmm, in either case, isolated or this, the stand sense won't work anymore. Aixun (AxxSolder as well?) uses a simple pulled-up GPIO to check if it's pulled down by the grounded tip's outer shell. This won't work with SELV as there is no connection to GND anymore. Since the outer shell has an internal connection to +24V, this problem can be solved by inverting the logic and using a voltage divider. Maybe that debounce circuit needs some adaption as well.Ohhh, one more thing... having a undgrounded/floating setup, what will happen when connecting both mains/SELV and USB to your (grounded) computer? Dave's oscilloscope scenario againAIUI, the SELV will be floating at a higher voltage with respect to earth (Y-Cap leakage). Connecting USB 1) creates a PELV szenario and 2) might kill the USB port on the computer.

author: drksy
author_rank: Regular Contributor
timestamp: November 07, 2023, 08:17:18 am
content: Quote from: c0d3z3r0 on November 06, 2023, 08:53:46 amYeah, this is a big problem isn't it? It's a compelling reason to make the controller board referenced to earth. If we have a floating supply feeding the controller and then connect a grounded USB cable, when the mosfet is on, the 24V goes from supply positive to mosfet to red to green (via tc) to earth (assuming tip is connected to earth), to the earth connection on your PC power supply, though the earth connection in the USB port, to the GND of the (no longer) floating controller, back to negative of the supply, essentially shorting it once again!In the CD-2BC reverse engineered schematic, they solved this problem by isolating the UART bridge connected to USB. Perhaps you could use one of those popular ADUM3160's to isolate the USB ground (and hence earth) from the pcb ground. But after the USB ground is isolated, the "safe" 5V would no longer be available (unless going through a dc-dc isolator).And yes, detecting whether the iron is the the stand is more convenient if the controller is earth referenced. So maybe it's just best practice as Marco Reps said to make the controller referenced to earth. It solves all of these weird problems at once.

author: c0d3z3r0
author_rank: Regular Contributor
timestamp: November 07, 2023, 09:44:44 am
content: Quote from: drksy on November 07, 2023, 08:17:18 amYes, the ADUM* would work perfectly here but the CC pins need isolation, too. Probably a simple digital isolator works here (there is some application example from AD, have checked roughly only, yet).Quote from: drksy on November 07, 2023, 08:17:18 amNo, it creates all the weird problems Aixun has, because this is exactly what they did. It would be just a copy of the T3A thenThe stand detect should be fine with that circuit I posted. Needs testing ofc

author: c0d3z3r0
author_rank: Regular Contributor
timestamp: November 07, 2023, 06:22:55 pm
content: BAV199 could be a good candidate for OpAmp protection

author: Warhawk
author_rank: Frequent Contributor
timestamp: November 08, 2023, 01:54:24 pm
content: Quote from: c0d3z3r0 on November 05, 2023, 02:32:33 pm(writing the post the second time as i accidentally closed the tab)I am sorry it took me longer to reply.Using Schottky diodes is relevant, they just need to be carefully selected. I checked some of my designs and the 1PS79SB70 device from nexperia is frequently used. Check the DS. Alternatively, I used BAS40 (still not perfect). I am with the team red, therefore esd protections such asTPD1E seriesfind often place on my boards. Note the maximum 10nA leakage. They are intended for digital signals but work for ADC protections too.[Thinking aloud]I also wonder, if protections such as D12, D1, D3 are really necessary. I would maybe add only 22pF ESD caps on the input and call it good to go. The current to the input pin of the ADC is limited by series resistors. This reminds me that it is important to find out if S/H time is long enough.Reverse polarity protection is maybe something I would like to see. D9 could be only unidirectional. Reverse polarity on the input would blow the fuse. Nevertheless, it would be likely more elegant to use an N mosfet + PWM charge pump from the MCU. That's often used for in automotive.I also wonder if using the OPA2333 makes sense here. I see it is configured as a difference amplifier here. This gives us ~60dB CMRR top. There are maybe parts for this. I like that the author used the charge bucket filter C15, C16. Not all opamps like transients when S/H circuit opens. There is often ringing.Regarding the diodes and TI.OPA333 datasheet, the chapter 7.3.2, describes the protection. Normally, we do not specify (characterize) ESD cells on the input as they are not intended to be used for operation. (there are few exceptions). What matters is the maximum input current to the pin. This is defined in the Absolute Maximum Ratings, chapter 6.1. I believe there's a typo 1 vs 10 mA (see the note 2).

author: Warhawk
author_rank: Frequent Contributor
timestamp: November 08, 2023, 02:01:33 pm
content: To all - I am genuinely interested in contributing to this project. Could someone give me a brief tl;dr; what the problem with grounding and Aisun is?I work nearly daily with small isolated power supplies (sn6501, 6505, 6507, ucc25800, LM5180, integrated modules, etc. etc.). It should not be a deal to do any kind of isolation necessary (including isolating signals). However, I need the problem statement.

author: c0d3z3r0
author_rank: Regular Contributor
timestamp: November 08, 2023, 04:48:32 pm
content: Well, there were different reports of weird problems the Aixun has, which are probably based on the fact that they use a PELV supply (secondary GND earthed).Only now I understood what might be the problem from this post:https://www.eevblog.com/forum/reviews/aixun-t3a-misbehaving-on-grounded-pcbs/Current flows not only from to the middle connector back to GND but also through the earthed thermocouple, the PCB, the earth connection.... that could be reason for the weird behaviour there and it's definitely not good soldering a grounded PCB with fine traces because there will be 4A (1/2 * 8 A) flowing through the PCBSee red arrows. I think this finally is the best argument for not using a PELV supply.

author: c0d3z3r0
author_rank: Regular Contributor
timestamp: November 08, 2023, 04:57:50 pm
content: Quote from: Warhawk on November 08, 2023, 01:54:24 pmUnsure about D12 but D1 and D3 are crucial for ESD protecting the GPIOs. Many T3A GPIOs were killed already. Check the T3A thread.

author: Warhawk
author_rank: Frequent Contributor
timestamp: November 08, 2023, 05:57:30 pm
content: Quote from: c0d3z3r0 on November 08, 2023, 04:57:50 pmIs there a circuit diagram somewhere? Do they have any ESD caps and current limiting resistors? I don't dispute the problem but there might be a different solution for that.

author: c0d3z3r0
author_rank: Regular Contributor
timestamp: November 08, 2023, 06:00:59 pm
content: Well, surely, there are always multiple options for one problem. What's the problem with just using (better chosen) diodes?Schematics:https://github.com/c0d3z3r0/aixun_t3a_rev/blob/master/schematics/aixun_t3a.pdf

author: AxxAxx
author_rank: Contributor
timestamp: November 10, 2023, 03:45:44 am
content: First of all, really nice to so much engagement and discussion about AxxSolder. I am at the moment in the djungle in southern india, turns out they have limited access to kicad and internet here. Getting home in about two weeks.Some thoughts:I will break out the AxxSolder hardware to a separate github repository (AxxSolder_hw) when I get home from my vacation. That make sense as hardware and software can then be released and versioned independetly. Git submodules could also work but it also makes it a bit more complicated for someone not used to git and git submodules.@Pooya, yes, please list all issues you find.If you list them here I'll transfer them to "Github Issues" so that they are collected in one place and it is easy to work on them.At the moment the Temperature measurement is "all over" when no thermocouple (Cartridge) is present, I know. This is already documented as a Github Issue. One way to detect if no Cartridge is present is to apply a very fast heating cycle and read the current response. That way also faulty cartridges could be detected.There is no implemented current measurement at the moment. I also need to implement current measurement in order to do proper PID control with feedforward model based control.If a temperature model is created for the tip it can be calculated how much energy is required to raise the tip to a final temperature. By integrating voltage*current for a specific amount of time that final temperature should be reached. A automatic calibration routine could be run to measure the thermal mass and heat dissipation of each tip.Next to a thermal properties detection routine I think there should be a temperature calibration routine. By using this routine the user should be able to go through a couple temperature points and input the real measured temperature, measured by an external termometer. This in order to account for variations in components and tip geometry. The original JBC stations I have access to do only have a global temperature offset value as far as I know.Neither of the above routines should be mandatory to use though. Just be there to increase accuracy and performance of thermal regulation if needed.There was also a question about why not the built in USB-C PD support of stm32g4. Basically because I have never used it before.. But after reading about it, it looks like a nice solution! I have to look more into it. A possible downside is that I'm running out of pins on the current MCU and an external USB-C PD controller does use fewer pins from the MCU, only two I2C lines.I will investigate this further. I will also look into the fact that 240W USB-C PD is coming and what that brings. That would be quite cool. Having a 240W soldering iron powered by usb! Can it really be possible? Downsides?As for the grounding/isolation discussions: I believe that you guys have really valuable ideas and experience in this subject. This is not my main expertise so I'm glad to see that you want to contribute in this area.@eliocor will sponsor the project with T115 handle/cartridge. This will enable me to measure the thermocouple characteristics, tune a initial PID as well as determine how this handle is detected (which pins are shorted in the handle). I believe that there is another pin that are used to sense if a T115 handle is detected than T210. As the current hardware does not have that pin automatic detection of T115 will most probably not work on the current hardware. But I'll implement that for next hw release. Highly aporeciated!With this said. I am Happy to invite everyone wanting to contribute to the project. Fork the AxxSolder repo and submit a pull request.

author: AxxAxx
author_rank: Contributor
timestamp: November 25, 2023, 02:04:24 pm
content: Ok, back to my home lab in Sweden!I have since I came back done some firmware upgrades on AxxSolder. There is now a settings menue where you can set a number of parameters which are then saved to non-volatile flash memory, for example start-up temperature and "sleep time".I have also started to implement current measurement and which will be used in temperature control and tip detection.I have also updated my original JBC cartridge layout with the cross-sections. This because I realized that there are problably not only one TC in the C245 cartridges but 3 TC's.. Here is the updated post:https://www.eevblog.com/forum/projects/axxsolder-jbc-soldering-controller/msg5124267/#msg5124267)Regarding the hardware.I think the next steps are to implement USB-C PD power and DFU and take a look into the tip grounding topic.I can drive and implement the USB-C features but I feel like I could get some help with a proper grounding solution.@Warhawk you mentioned you were interested in contributing and had working experience in this topic. I would be happy to get your support (as well as anyone else's). I created a discord channel for a more chat-like discussion forum about AxxSolder hardware.https://discord.com/invite/AwpHEmsyKj

author: neverendingstudent
author_rank: Regular Contributor
timestamp: April 03, 2024, 11:31:07 pm
content: Hey c0d3z3r0, I noticed in your post signature you link to the T3A reverse engineering project on Github. Do you know of a similar project for the T420D? Is anyone reverse engineering that model / making open source firmware?

author: c0d3z3r0
author_rank: Regular Contributor
timestamp: April 05, 2024, 11:06:44 am
content: Quote from: neverendingstudent on April 03, 2024, 11:31:07 pmNo idea, sorry

author: VetalSkat
author_rank: Newbie
timestamp: September 18, 2024, 09:00:24 am
content: Hi, Axel!I liked the implementation of your soldering station. I want to repeat, but I will not use USB PD. I have a question: is it possible not to install elements related to USB C - Power Delivery? Do I need to make changes to the firmware?

author: AxxAxx
author_rank: Contributor
timestamp: September 22, 2024, 05:15:06 pm
content: I saw you posted the same question in the Discord channel, I answered you there!

author: vouager
author_rank: Contributor
timestamp: September 22, 2024, 11:42:53 pm
content: So,I wrote to you on YouTube and here again,I often use copies of JBC cartridges and that's why I think an option to calibrate the temperature of the soldering tip is a very good idea.Watch this video at 6:00But I missed your project more because of its compactness, color display, and especially because of the portable version. And I'll be very happy if you can implement something like that.

author: AxxAxx
author_rank: Contributor
timestamp: October 01, 2024, 07:41:35 pm
content: That is a good idea!I'll put it on the list of things to integrate further on!

author: AxxAxx
author_rank: Contributor
timestamp: November 07, 2024, 08:37:05 pm
content: Quote from: vouager on September 22, 2024, 11:42:53 pmThis will be implemented in the next fw release 3.2.2!

author: vouager
author_rank: Contributor
timestamp: November 17, 2024, 08:57:27 pm
content: Hello,I saw your message here yesterday and I'm just looking at your github and lo and behold, 3.2.2 is already there!https://github.com/AxxAxx/AxxSolder/releases/tag/v3.2.2That's great!Do you have any videos with this new option?Now I can start building it because almost all my wishes have been fulfilled!That's why I'd like to ask you whether the current hardware v3.1 will stay the same or is a new one coming soon?Thanks,Regards,

author: AxxAxx
author_rank: Contributor
timestamp: November 18, 2024, 07:28:47 pm
content: Hi!No I do not have any video of it.But basically you will have 6 setpoints: 100, 200, 300, 350, 400, and 450 deg C.By default all these are at their nominal values.You can set AxxSolder to one temp that you want to calibrate (or all one by one).And when AxxSolder stabilizes around the setpoint, let's say 300 deg C you measure the actual tip temperature.Let's say you get 302 deg C.You then input 302 deg C to the calibration point 300 and save the setting.AxxSolder will then use this calibration point and correct the temperature accordingly. It will do so linearly between all calibration points.I think the hardware 3.1 will stay as it is for the single iron AxxSolder. I do not see any reason to change it at this point.I think however that I want to make a tweezer compatible AxxSolder in the future but I do not know when that will be availible.First I have to buy a AM120 tweezer and tips to do the development on. There has been several kind users in the Discord Server sponsoring me towards the goal of buying the tweezers. We are soon there, missing 50 Euro at the moment. As soon as I got the money to buy the tweezers i can start the development of AxxSolder with tweezer support.Code for the 6-step temp calibration:Code:/* Adjust measured temperature to fit calibrated values */if(sensor_values.thermocouple_temperature < 100){sensor_values.thermocouple_temperature = sensor_values.thermocouple_temperature*(flash_values.temp_cal_100)/100.0f;}else if(sensor_values.thermocouple_temperature < 200){sensor_values.thermocouple_temperature = (sensor_values.thermocouple_temperature - 100.0f)*(flash_values.temp_cal_200-flash_values.temp_cal_100)/100.0f + flash_values.temp_cal_100;}else if(sensor_values.thermocouple_temperature < 300){sensor_values.thermocouple_temperature = (sensor_values.thermocouple_temperature - 200.0f)*(flash_values.temp_cal_300-flash_values.temp_cal_200)/100.0f + flash_values.temp_cal_200;}else if(sensor_values.thermocouple_temperature < 350){sensor_values.thermocouple_temperature = (sensor_values.thermocouple_temperature - 300.0f)*(flash_values.temp_cal_350-flash_values.temp_cal_300)/50.0f + flash_values.temp_cal_300;}else if(sensor_values.thermocouple_temperature < 400){sensor_values.thermocouple_temperature = (sensor_values.thermocouple_temperature - 350.0f)*(flash_values.temp_cal_400-flash_values.temp_cal_350)/50.0f + flash_values.temp_cal_350;}else{sensor_values.thermocouple_temperature = (sensor_values.thermocouple_temperature - 400.0f)*(flash_values.temp_cal_450-flash_values.temp_cal_400)/50.0f + flash_values.temp_cal_400;}Regards,Axel Johansson

author: vouager
author_rank: Contributor
timestamp: November 18, 2024, 07:50:55 pm
content: As far as I have researched, a tweezer SHOULD work with existing hardware.In fact, despite the tweezer being used, the same pins as single are used.Only the detection runs via two diodes and a resistor! Have you ever seen this link?https://lajtronix.eu/2024/02/08/jbc-3-tool-selector/regards

author: AxxAxx
author_rank: Contributor
timestamp: November 18, 2024, 09:04:09 pm
content: Yes I have seen it.In the AN115 and NP115 there are two diodes which allows one of the two legs to be heated during the positive period of the heating AC and the other during the negative period.However on AM120 and larger tweezers there are no diodes as far as I know. There they use two separate heating circuits with the 6 connections:GREENRED_1RED_2BLUE_1BLUE_2Sense_resistorSo I think that for AM120, PA120, tweezers an AxxSolder with two channels (dual: MosFETs + gate drivers + op-amps + current sense + tip detection) should work.To drive the AN115 an NP115 one would need another design using AC (AxxSolder runs on DC) or a H-bridge based inverter design to create a alternating current.I did some early proof of concept with a borrowed pair of AM120:

author: vouager
author_rank: Contributor
timestamp: November 19, 2024, 08:33:53 pm
content: So, I'll have a tweezer here, but I don't know the principle of how they work.But for alternating current you can use a relay (SSR) which is powered by the existing power supplyand switch contacts to get alternating current from the transformer!I've already bought a 2x12V 6Ah toroidal transformerand I ordered one from Aliexpress one cheep OLED SPI 2" display.https://de.aliexpress.com/item/1005006852580250.html?We'll see when the time comes whether it runs smoothly.Regards,

author: AxxAxx
author_rank: Contributor
timestamp: November 22, 2024, 06:10:47 am
content: Nahh, I do not want to go the path with toroidal transformer.AxxSolder will stay DC powered

author: vouager
author_rank: Contributor
timestamp: November 22, 2024, 07:42:58 pm
content: Yes my frend!I have a few SMPT power supplies up to 10A with adjustable output voltage of 12-32V.In addition, this transformer + power supply board with super filter on the output is also 12 or 24V DC voltage.I will test which power supply type works better for my needs. (4-6 layer boards with large ground areas)SMTP Power is great, but not always! that's why JBC still has transformers inside.

author: vouager
author_rank: Contributor
timestamp: February 17, 2025, 05:35:10 pm
content: Hello guys,For everyone who wants to build this wonderful project, here are suitable connectors for JBC soldering irons.https://de.aliexpress.com/item/1005002522875446.html?

author: Sergey61
author_rank: Newbie
timestamp: September 09, 2025, 12:07:48 am
content: привет. при установке дисплея 2.0 tftspi gmt020-02-7p,на экране только мусор,это дисплей не подходит?все соединения проверены.