hybridfree/eevblog-posts huggingface dataset:
GW Instek Oscilloscope - Page 1
Forum section: electronics / beginners

author: Orlando
author_rank: Newbie
timestamp: October 28, 2018, 09:52:37 pm
content: Im looking to make an important investment on a oscilloscope, right now im looking particularly at thisGW Instek, I would really apreciate if you give me your opinions or suggest me another in the same range (doesnt have to be gw instek)GDS-220Portable 2-channel oscilloscope, with a bandwidth of 200 MHz, a recording length of 1 Mp, and a sampling rate of 1 GS / s. It also has a DMM of 5,000 counts, accuracy of ± 20ppm, has a capacitive touch panel of 7 "and its excellent battery allows you to work in constant operation up to 4.1 hours.

author: Johncanfield
author_rank: Regular Contributor
timestamp: October 28, 2018, 10:36:03 pm
content: What's your budget? Is a small physical size a requirement?

author: Orlando
author_rank: Newbie
timestamp: October 29, 2018, 03:17:49 am
content: My budget is 1300-1500 USD, and yeah preferable small size, but any suggestion is welcome, thank you

author: tautech
author_rank: Super Contributor
timestamp: October 29, 2018, 06:48:30 am
content: Quote from: Orlando on October 29, 2018, 03:17:49 amTBH you'd be better off with a separate DMM and scope.Why does the small form factor interest you ?Must it be totally portable and not a bench unit ?
GX12-5 Pin Switch - Page 1
Forum section: electronics / beginners

author: Toybot
author_rank: Newbie
timestamp: July 11, 2020, 03:49:33 pm
content: I am trying to find a way to to switch between 2 GX12-5 Pin ports. I have tried google, alibaba/express, and searched here too and found nothing. Hoping someone can help me out here and point me in the right direction.Thanks!

author: tooki
author_rank: Super Contributor
timestamp: July 11, 2020, 06:40:24 pm
content: Buy the right connectors and use a 5-pole switch to switch them?Or build a little box with some relays to switch the 5 lines?(In both cases, you might be able to get away with switching just 4 lines if one of the lines is ground that can be left connected.)

author: Nominal Animal
author_rank: Super Contributor
timestamp: July 11, 2020, 07:44:24 pm
content: Mouser hasGrayhill 5-pole, 2-position, break-before-make rotary switchesfor about 20€ apiece. Expensive, but looks exactly what you'd need. (PDF datasheet.)Essentially, the single connector would connect to pins C1, C2, C3, C4, and C5; one of the switched connectors would connect to pins 1, 3, 5, 7, and 9, and the other to pins 2, 4, 6, 8, and 10. Pins C1-C5 are in a single plane (perpendicular to the rotary axis), and pins 1-10 on another plane (also perpendicular to the rotary axis).On the cheaper side, Mouser also hasAlpha 6-pole, 2-position, break-before-make rotary switchfor about 5€ apiece. (PDF datasheet.)For this one, you'd connect each inner pin to the single GX12 connector, and the two closest outer pins to the corresponding pin on the two other GX12 connectors. There is one extra pole (three pins on the switch) you'll leave unconnected.Note that you will definitely want to use non-shorting or break-before-make switches, so that when turning the knob, the two outgoing connector pins are never connected together.In general, look for 5- or 6-pole, 2-position, non-shorting/break-before-make switches. The above links are to Mouser EU, but you should find some in the $5 - $35 range in USA easily. The Grayhill ones look to be very well made and robust (but I haven't used them; I'm poor and cheap), but even the cheaper Alpha ones and similar should work for most cases.If this is basically just a switch box, I'd definitely use a Hammond cast-aluminium box for this. They're robust and affordable, and the conductive box (connecting all connector metal parts together) will help with EMF (electromagnetic radiation either emitted from or inducing voltages to the signals).
Gyrator, the fifth element - Page 1
Forum section: electronics / beginners

author: Wytnucls
author_rank: Super Contributor
timestamp: September 07, 2013, 07:16:44 am
content: Conceived in 1948, with several applications, one of which was to replace bulky inductors, the gyrator is rather mysterious.Are they still used today? Could someone familiar with their use, care to explain how they work?

author: IanB
author_rank: Super Contributor
timestamp: September 07, 2013, 07:37:21 am
content: The Wikipedia article contains many details, does it not?How they work:A four terminal circuit element with a set of linear equations describing its behavior. The mathematical properties given by these equations can be simulated by a circuit built out of capacitors, resistors and op amps. In some sense this would be just like an analog computer.Applications today:As noted by the Wiki article, active circuits can simulate inductors and other components with apparent inductances much higher than a physical passive inductor could have of the same size. Applications are found in active filter circuits, for example.

author: EEVblog
author_rank: Unknown
timestamp: September 07, 2013, 08:08:37 am
content: The gyrator has been on FF video list for some time.Yes, they are still used for filters and other stuff that would otherwise need really high physical inductance values.They do actually work just like inductors, the only difference is there is (obviously) no ability to store energy in a magnetic field.

author: Wytnucls
author_rank: Super Contributor
timestamp: September 07, 2013, 11:38:53 am
content: The Wikipedia article is interesting but requires a vast knowledge of electronics to make any sense (2-port device, non reciprocal, network realization, isolators, circulators, current/voltage/impedance inverter), but doesn't explain how the device actually works.http://en.wikipedia.org/wiki/GyratorI find this circuit animation of the gyrator more beneficial to the layman:http://www.falstad.com/circuit/e-gyrator.htmlLooking forward to Dave's take on the device, in a future video.Here is a good write-up on the subject by Bryan Morrison and Thomas Lynch:http://schematicsforfree.com/archive/file/Audio/Circuits/Filters/GYRATORS/Gyrator%20Theory.pdf
Gyro signal conditioning 1.5v +- 1v to 0-10V - Page 1
Forum section: electronics / beginners

author: Arowana
author_rank: Newbie
timestamp: November 19, 2013, 02:14:15 pm
content: Hello, I'm trying to read a analog gyroscope using a canbus io-module. The gyro ST LPY410AL outputs a 1.5 +- 1V voltage for the angular rate and a 1.5v reference voltage. The IO module has a 0-10v 10bit adc and provides a 10v reference voltage.I have designed a amplifier circuit that will take the gyro output and convert it to a 0-10v signal.e.g. Vout = 0.5*10v_ref + (V_in-gyro_ref) * 5I'm a programmer by trade so the digital side of things is no problem, but this is my first opamp design.What I would like to know is:Is my design sound?What opamp would you recommend?The bandwidth is very low, the gyro is measuring the turnrate of a heavy vehicle, so its tens of herts only. The iomodule samples at 40hz.I have attached a shematic of the circuit and a spice diagram that I used for simulationAny help appreciated.

author: Arowana
author_rank: Newbie
timestamp: November 25, 2013, 11:02:24 am
content: Anyone?

author: fcb
author_rank: Super Contributor
timestamp: November 25, 2013, 11:16:20 am
content: Looks like a diff-amp job and thats what you've used. I haven't got time to work through the math at the moment.However I would probably do it slightly. I would use a differential amp firstly on the gyroout and gyroref to give you say +/-5v w.r.t. 0V signal, then a second differential amp using the adc reference to take you to 0-10v.Remember you are only compensating for the 0g posistion by using the reference, scaling is upto your software.
H-Bridge Braking (IFX9201SG) - Page 1
Forum section: electronics / beginners

author: normalverbraucher
author_rank: Newbie
timestamp: May 07, 2019, 02:54:40 pm
content: Hi,I have been playing around with the Infineon IFX9201 Integrated H-Bridge lately, and I was unable to figure out how to brake a DC motor with this IC. There is no brake functionality specified in the datasheet (see attached pic).Does anyone know of an easy way to quickly stop a DC-motor with this chip?

author: soldar
author_rank: Super Contributor
timestamp: May 07, 2019, 03:18:32 pm
content: Reverse?

author: Etesla
author_rank: Regular Contributor
timestamp: May 07, 2019, 03:52:09 pm
content: I think it depends on the direction the motor was already spinning.Say you had HS1 and LS2 on, and then you wanted to break the motor. To break, you would turn off HS2 and LS2, and turn on just LS1. This would provide a reverse current path through LS1, through the diode in LS2, and through the motor, in the opposite direction breaking it.The other case would be having HS2 and LS1 on to start, and then to break, turning off HS2 and LS1, and turning on just LS2.I think turning on LS1 and LS2 at the same time for breaking would also work for both starting cases, even though one of the mosfets still shouldn't actually be conducting a whole lot during that time, but this simplification may be worth it.I have never tried this, but this link makes me thing that this may work:https://electronics.stackexchange.com/questions/56186/how-can-i-implement-regenerative-braking-of-a-dc-motor

author: Benta
author_rank: Super Contributor
timestamp: May 07, 2019, 04:25:36 pm
content: What the data sheet calls "Free Wheeling" is actually braking.

author: pwlps
author_rank: Frequent Contributor
timestamp: May 08, 2019, 07:10:53 pm
content: Quote from: Etesla on May 07, 2019, 03:52:09 pmYes, this article explains it very nicely. So to enable breaking the PWM should switch very fast between "forward" and "free wheel forward" (and this is what we see in the driver truth table). If the PWM frequency is high enough (relative to the L/R time constant of the motor) then on decreasing the PWM duty cycle the motor will act as a buck–boost converter, supplying current to the PS (this is regenerative braking - check if the PS can accept reverse current). So in principle there is nothing special to do, progressively decreasing the PWM duty cycle will enable breaking.This won't work anymore when the motor EMF drops below the diode threshold, but then you can probably safely switch to reverse.

author: MarkF
author_rank: Super Contributor
timestamp: May 09, 2019, 12:44:15 am
content: Quote from: Etesla on May 07, 2019, 03:52:09 pmNone of this is possible. Look at the truth table the OP posted.

author: Jwillis
author_rank: Super Contributor
timestamp: May 09, 2019, 06:04:02 am
content: There are three types of DC electric motor braking. 1 Plugging or reverse current braking. 2 Dynamic Braking or Rheostatic braking .3 Regenerative Braking or kinetic energy of the motor is returned back to the power supply.
H-Bridge control with one signal, my mind is drawing a blank. - Page 1
Forum section: electronics / beginners

author: PeterFW
author_rank: Frequent Contributor
timestamp: March 24, 2016, 12:59:16 am
content: Hello!I like to think i know a bit of this electronics stuff and most likely i will have the solution as soon as i hit the send button.But my mind is drawing a complete blank for some time now.The motor driver in question is the VNH2SP30 from ST.It has 2 pinputs for the direction control but i would just like one signal to control it.High -> CW and Low-CCWFairly straight forward but... amongst all these trees, i can not see the forrest.Will someone point me in the right direction?Thank you!Greetings,Peter

author: langwadt
author_rank: Super Contributor
timestamp: March 24, 2016, 01:14:25 am
content: drive one input, use inverter to drive other input

author: danadak
author_rank: Super Contributor
timestamp: March 24, 2016, 02:09:29 am
content: When you drive inputs 180 degrees out of phase make sure your timingis such that both inputs are never on at the same time. That's to insureno two vertical transistors in the bridge are on at the same time, therebyshorting the power supply to ground.Regards, Dana.

author: PeterFW
author_rank: Frequent Contributor
timestamp: March 24, 2016, 02:27:05 am
content: Quote from: langwadt on March 24, 2016, 01:14:25 amThank you very much, problem solved with one Fet and a resistorGreetings,Peter

author: PeterFW
author_rank: Frequent Contributor
timestamp: March 24, 2016, 02:32:19 am
content: Quote from: danadak on March 24, 2016, 02:09:29 amThanks, i am aware of that.In this case though, the motor driver interprets this as breaking.So, no problem there, i think... maybe you can back me up on thatPage 14, Table 12. Truth table in normal operating conditions:https://www.pololu.com/file/0J52/vnh2sp30.pdf

author: danadak
author_rank: Super Contributor
timestamp: March 24, 2016, 10:41:03 am
content: Yes, driver takes care of protection for you.Regards, Dana.

author: PeterFW
author_rank: Frequent Contributor
timestamp: March 24, 2016, 04:49:12 pm
content: Quote from: danadak on March 24, 2016, 10:41:03 amThanks!

author: SL4P
author_rank: Super Contributor
timestamp: March 24, 2016, 09:31:14 pm
content: Quote from: PeterFW on March 24, 2016, 02:32:19 amOn any other controller, I'd agree with that.
H-bridge current sense - Page 1
Forum section: electronics / beginners

author: SenSeS
author_rank: Contributor
timestamp: February 18, 2015, 12:57:30 pm
content: Hi all,I need an H-bridge that is capable of controlling a DC-motor and measuring the current it uses. The problem is that it’s hard to find H-bridges that have acurrent sense pin and that aren’t overkill for my application (I only need 2 inputs and 2 outputs and I need a low voltage one since my DC runs at a maximum of 6V). This is why I thought about using an H-bridge without current sense pin and instead measuring the current that returns from the DC-motor to GND. Are there any drawbacks to this as opposed to having a special purpose current sense pin on the H bridge itself? If not, then why do these current sense pins even exist?Thanks in advance!SenSeS

author: hamdi.tn
author_rank: Frequent Contributor
timestamp: February 18, 2015, 01:05:53 pm
content: L298 , it has 2 H-bridgeyou can always build your own single H-bridge as you said and put a resistor between it and the ground it's the same thing.i personally use L298 even if i need only one bridge.when used with motor, current sense can detect if the rotor is blocked , can be used to detect limit without using a limit switch.

author: SenSeS
author_rank: Contributor
timestamp: February 18, 2015, 05:43:27 pm
content: Thanks for the info, however I don't really like the idea of only using half the in/outputs of the H bridge, cause lets say I'd want to make multiple PCBs, or that I need small PCB's, then there really is a cost to having such an H-birdge. I'm sort of surprised that the kind of H bridge I need seems hard to find because it seems fairly standard. Or are H-bridges only used by hobbyists? Do all commercial products implement their own H-bridge? And if so, why? Doesn't this take up more space than a small simple 8pin H bridge? It also seems more error prone.

author: max_torque
author_rank: Super Contributor
timestamp: February 18, 2015, 07:18:38 pm
content: Remember that, depending on where the current is sensed, that current is not necessarily the loads current! IE if it is sensed on the output of the H bridge to gnd, as is often the case, it is only the same as the load current at 100% duty!Check your devices datasheet to understand where the current is measured before assuming anything

author: K1JOS
author_rank: Regular Contributor
timestamp: February 19, 2015, 01:23:45 am
content: Look at Pololu.com they have sevferal reasonably priced high current H drivers with built in bidirectional current sensinghttps://www.pololu.com/category/82/pololu-high-power-motor-drivers

author: DutchGert
author_rank: Frequent Contributor
timestamp: February 19, 2015, 01:12:55 pm
content: Try the VNH5180A-E from ST or one of there other VNH series H-Bridges.Also, Polulu sells boards that use those chips
H-bridge doesnt supply any current.  - Page 1
Forum section: electronics / beginners

author: Dmeads
author_rank: Regular Contributor
timestamp: September 08, 2019, 08:52:26 pm
content: Hi folks!I followed the Lewis Loflin H bridge tutorial for an SPWM signal which is greatI have included my schematic, but I used a square wave to simulate in LTspice instead of the SPWM switching.also I used IRFZ24N instead of IRFZ44N MOSFETs.I get a nice sinusoidal output with a high resistance RC filter, but no matter what load i stick on the bridge, my power supply says the H bridge never draws more than 1mA, which from simulation I learned is for the 10kohm pullup resistors with a 10V supply voltage.Does anyone know how my H bridge can output more current? I would eventually like to use it to drive an induction motor.Thanks!

author: james_s
author_rank: Super Contributor
timestamp: September 08, 2019, 08:57:09 pm
content: Your circuit is not the same. One has all N channel mosfets, the other has N and P channel mosfets, at least it looks that way from the picture.

author: garethw
author_rank: Regular Contributor
timestamp: September 08, 2019, 09:04:13 pm
content: You’re trying to turn on an N-channel mosfet by grounding it and that will not work. You can’t swap p and n channel devices without reconfiguring the circuit.Sent from my iPhone using Tapatalk

author: Mechatrommer
author_rank: Super Contributor
timestamp: September 08, 2019, 09:51:44 pm
content: if you do that in real life, you will burn all the mosfets.

author: mc172
author_rank: Frequent Contributor
timestamp: September 08, 2019, 09:58:54 pm
content: Quote from: Mechatrommer on September 08, 2019, 09:51:44 pmWell that's a great help to the OP, nice one for helping him to understand why.

author: Mechatrommer
author_rank: Super Contributor
timestamp: September 08, 2019, 10:14:01 pm
content: Quote from: mc172 on September 08, 2019, 09:58:54 pmi thought the OP can figure that out but since you asked, because the upper NMOSFETs will by default turned ON due to pull up resistors R4 and R5 (if their respective controller LO). say if V2 toggled HI, M3 will be turned ON, since M2 is ON (V3 LO), it will create a short M2 to M3 and poof, vice versa on V3 HI, M1 -> M4. the safe state is when V2 == V3 in which case motor will be clamped to either V1 or GND, and those states are useless to drive a motor spinning. ymmv.
H-bridge motor driver circuit - Page 1
Forum section: electronics / beginners

author: Tantalum
author_rank: Regular Contributor
timestamp: December 28, 2024, 01:30:06 pm
content: HelloI have a little project. I need to driver a small linear actuator, like on this picture:The specs:- ESP32 Wifi module- H-bridge motor driver (don't know exactly which one yet, but it doesn't matter)- 24VDC power over a 20m long cable- in a waterproof box outdoorsNow the questions:Q1: Do I need anisolatedDC-DC converter?Q2: Is it advisable to use a surge stopper like a LTC4366 (burns the peak surge voltages in a MOSFET), or are passive protections (Diodes/Movs) enough?Q3: Is it better to use an opto-coupler on the motor driver input-side?Thank you for your help

author: Siwastaja
author_rank: Super Contributor
timestamp: December 28, 2024, 01:38:31 pm
content: Q1: No, Q2: No for LTC4366, no for MOVs; what are "diode protectors"?, Q3: No;but this rises a question of why you think asking those questions make any sense, and what are the things you are missing?Therefore,Quote from: Tantalum on December 28, 2024, 01:30:06 pmI think this does matter. The design of the motor driver itself is the key.

author: Tantalum
author_rank: Regular Contributor
timestamp: December 28, 2024, 04:01:19 pm
content: Well I was thinking to use a DRV8871 (45V/3.6A max) which seems more than enough for a 12V 0.6A motor like the one I'm using.

author: Siwastaja
author_rank: Super Contributor
timestamp: December 29, 2024, 07:03:18 am
content: Quote from: Tantalum on December 28, 2024, 04:01:19 pmThen the important points are PCB layout and DC link capacitance. A TVS on power input might be a good piece of protection.What drives the inputs of DRV8871?
H-Bridge output measurements - Page 1
Forum section: electronics / beginners

author: PeterFW
author_rank: Frequent Contributor
timestamp: April 27, 2016, 09:05:02 pm
content: Hello!So, since none of the cheap ebay modules do what i want, i have scribbled my own simple H-Bridge with two IRS2184 and a few IRL3803.Now, i can not simply put the scope probes across the output and the supply is not floating.So i would connect one probe on each output (two channels) and the GND clip to the GND point before the H-Bridge.And... am i correct that it would be a bad idea if i were to connect a electronic load on the output? So i am limited to just a resistor to simulate a load.Am i correct?The whole thing just drives a resistive load at <12V with just 5A for now.Greetings,Peter

author: danadak
author_rank: Super Contributor
timestamp: April 27, 2016, 10:07:52 pm
content: "And... am i correct that it would be a bad idea if i were to connect a electronic load on the output? So i am limited to just a resistor to simulate a load."Yes, load should be R, L type load, not an active regulator load. If you tried the latter itcould be a constant current load, but its compliance range should be limited to H Bridgecomponent breakdown / safe area limits. And then not a polarity changing environment.I may be mistaken on this but electronic loads normally do not regulate a switched polarityenvironment ?Regards, Dana.
H bridge using motherboard CPU power supply parts. - Page 1
Forum section: electronics / beginners

author: Alana
author_rank: Frequent Contributor
timestamp: March 25, 2013, 07:41:19 pm
content: I have lots of old motherboards and i was thinking of using power mosfets and power mosfet drivers from CPU power supply as parts of H-bridge.I'm mostly concerned for driver chip - normally this chip works around 1MHz and my H-bridges would be used on model railway DCC boosters that work around 10kHz.Chips i have are:HIP66-01ACBISL6609SC1211Sthose would be ok voltagewise for DCCADP3418, ADP3110, ADP3418Kthose go only up to 13V but i if they can control mosfets on DC they will be usefull too
HACK ? Lipo / Li-ion Battery Voltage alarm. - Page 1
Forum section: electronics / beginners

author: user1235423643
author_rank: Regular Contributor
timestamp: September 03, 2016, 02:50:48 pm
content: does anyone know how to hack one of these to alarm at a different voltageit will alarm if any cell drops under 2.7~3.8Vwhat about alarm on TOTAL voltage rather then per cell?and a a bigger alarm total range? (if the battery total cells was 30v... alarm at 20v)thanksspecs:1-8S Lipo/Li-ion/Fe RC helicopter airplane boat etc Battery Voltage 2 IN1 Tester Low Voltage Buzzer AlarmFeatures:1-8S Lipo/Li-ion/Fe RC helicopter airplane boat etc. Battery Voltage 2 in 1 Tester Low Voltage Buzzer AlarmUse for 1-8S Lipo/Li-ion/LiMn/Li-FeVoltage detection precision: +_0.01V.Unit voltage display range: 0.5~4.5VTotal voltage display range: 0.5~36V1S test mode voltage range: 4-15VLow voltage alarm mode for 2-8SAlarm set value range:OFF~2.7~3.8VSpecification:Size: 40mm x 25mm x 11mmOriginal box: NONet weight: 9gColor: RedPackage Content:1 x 1-8S Battery Voltage Buzzer Alarm

author: amyk
author_rank: Super Contributor
timestamp: September 04, 2016, 12:56:24 am
content: You would have to investigate the schematic and see how it senses the voltage. If they're using a discrete voltage reference + divider then you can change the resistors, otherwise if they're using a standard lion protection IC (like a DW01) the voltages will be fixed.

author: jwrodgers
author_rank: Unknown
timestamp: September 06, 2016, 11:03:20 am
content: The reason it alarms if any cell drops too low is because the cell will be damaged if it is discharged below a certain point. (I prefer not to take any cell in my Li Ion battery packs below about 3.1 volts.) If you only monitor the total voltage, you may miss when a cell is being drained too low due to imbalances between the different cells. The pack voltage may still be ok for the application, but continuing to use it with a low cell can lead to damage in one cell that renders the complete pack useless.I have assumed here that you want to use it with a battery pack to get longer from it, but you may have an innovative application that I have missed, if so I apologise in advance.

author: user1235423643
author_rank: Regular Contributor
timestamp: September 09, 2016, 09:11:44 am
content: so does anyone know how to hack these, or?
PWM PMIC for hacking up a small display? - Page 1
Forum section: electronics / beginners

author: joeyjoejoe
author_rank: Frequent Contributor
timestamp: November 04, 2018, 03:46:25 pm
content: I got some SWAG that is a simple LED-backlit case that let's you put in letter and customize a message. Inside is simply two LED trips, a 10Ohm resistor and it runs of 3xAAA.I'd like to hack it up to get a bit more life, and possibly make it run off a single 18650 with a simple protection circuit and microUSB charging. Also, ditch the resistor for something more power efficient.I could do a simple 555, but it got me to thinking.. this seems like a straightforward application. Are there existing IC's that have a PWM output, can drive LED's and have a low current? Do they have a name I can search for? Category in Digikey?(I tried some google-fu for that but got mostly complete LED driver circuit boards or complete LED drivers themselves...)
Hacking a novelty cup? - Page 1
Forum section: electronics / beginners

author: AndrewM
author_rank: Contributor
timestamp: June 26, 2017, 02:50:08 am
content: Hi,I got a cup at a concert I went to yesterday. It had some lights on the bottom that lit up, flashed, at different times in the concert. I want to figure out how to control it myself if possible, but I haven't been able to find any information on the chips on the board.I have noticed that removing/replacing the battery makes all the LEDs flash three times. I'm guessing its some sort of startup self-check.I've attached photographs to this post. The numbers on the wireless chip are:219AA801653Does anyone have any ideas/suggestions?Thanks

author: sleemanj
author_rank: Super Contributor
timestamp: June 26, 2017, 03:00:29 am
content: It is bluetooth according to the website (buzzconnect.io) I thinkA search for 219A and bluetooth brings this uphttps://www.aliexpress.com/store/product/LED-bluetooth-RGB-controller-DC12-24V-input-2A-3CH-output/701799_32271275419.htmlLong shot but maybe the app works.The 8 pin chip I would guess as a PIC12

author: bktemp
author_rank: Super Contributor
timestamp: June 26, 2017, 04:16:24 am
content: The 8 pin chip has a Holtek logo on it and you can clearly read HT48**2. So it is most likely a cheap Holtek 8bit microcontroller.Based on the antenna size it doesn't look like 2.4GHz to me, more like 315/433MHz.I couldn't find anything for that markings, but the module reminds me of a RFM69.

author: amyk
author_rank: Super Contributor
timestamp: June 26, 2017, 05:58:20 am
content: It is not BlueTooth. That is a CMT2219A.The MCU is a Holtek HT48 series (can't read exact part) --- likely OTP.
Hacking a treadmill. Need info on a shift register.. - Page 1
Forum section: electronics / beginners

author: eevfan007
author_rank: Contributor
timestamp: January 25, 2014, 12:57:40 am
content: Hi!I just bought a treadmill, and though I'd do some hacking. I have identified the main logic, and the keys (like speed, elevation etc) all goes into a shift register, that is then passed on to the main processor. My question is simple. I have not done any work with shift registers before, and this model uses the 74HC164N.DATASHEET HERE:http://www.nxp.com/documents/data_sheet/74HC_HCT164.pdfAm I correct in my assumption that this will send serial data to the main processor and back to the 74HC164? And am I further correct in my assumption that if I get in the middle of that I too can send serial command to the processor to control the treadmill ?Some pictures:The keypads (like speed up, down etc. Very simple pcb)The shift register (with the connector from the first pcb with all the buttons). Shift register on the left.:The main chip and EEPROM:I can obviously solder directly onto the buttons, but I thought it might be possible to do all of this through serial. Can it?

author: Rerouter
author_rank: Super Contributor
timestamp: January 25, 2014, 01:07:46 am
content: Parrellel out serial in is for outputs not inputs,it also ripples the outputs, which is a poor design move, (shifting in new bits changes the outputs)Output the state you want, and then Clock high, this will shift the states across, so 0010000 becomes 1001000 (if asserting a 1)

author: eevfan007
author_rank: Contributor
timestamp: January 25, 2014, 02:12:14 am
content: Seems that I forgot to add the N at the end of the part number. If that's important. So: 74HC164N

author: strangelovemd12
author_rank: Regular Contributor
timestamp: January 25, 2014, 04:03:59 am
content: The "N" just denotes the package, in this case DIP14. If were in an SO14, for instance, it would be marked 74HC164D.This stuff (how to string together the right part number) is in the "Ordering Information" section. Some companies do a better job than others describing their coding system.
Hacking communication to 'smartify' my standing AC unit via what looks like UART - Page 1
Forum section: electronics / beginners

author: Bfreak
author_rank: Newbie
timestamp: June 15, 2025, 11:26:04 am
content: Hi all. I'm attempting to modify my arlec portable AC unit by placing it in another room to isolate noise and heat, and pump the cool air into another room. In the process, I'd like to hack the unit (probably via the communication between the front panel and the main board) via UART to control via an RPI pico W in order to monitor and control it via homeassistant, or something else.I'm a long time hobby engineer, but I've never reverse engineered a communication protocol. And I may have picked the wrong first battle here as it appear to be a proprietary protocol.Key observations:both directions has occasional messages. At first I assumed the main board updated the front panel with information for the 2 digit display, mode LEDs, and piezo speaker. Evidently this is not the case.The passive messages are 10s apart, first the front panel, then possibly a reply from the main board 300ms later.communication in both directions starts with a 4.5ms low, then 2.25ms high.normal data then starts with 0.25ms low times per bit(?)there are occasional 0.75ms lowsdata then finishes with a .5 ms low from the front panel to the board (RX on the board)and a .6ms low from the board to the front panel (TX on the board)Logic 2 software suggests baud of 4.032 kHzPulseview reading. Note that the UART decoding looks *close* but the timing is definitely not right on a few things, and the start/finish timings are unlike anything else I can find.Any suggestions here appreciated!I'm in this for the fun of hacking, so no suggestions for buying my way out of this problem, or using something like an IR repeater; I want to essentially be able to fully wirelessly replicate the unit's front panel.

author: Bfreak
author_rank: Newbie
timestamp: June 15, 2025, 11:27:08 am
content: Link to Github repo with a bit more info on my findings and an image from pulseview:https://github.com/Bfreak/arlecPA0803GBcontroller/tree/main

author: ledtester
author_rank: Super Contributor
timestamp: June 15, 2025, 10:35:36 pm
content: How do you know it's a UART protocol? That is, how do you there isn't a clock signal?What kind of chips are on the display board? That can help in figuring out the comms.You might get farther just reading the LEDs directly via phototransistors or voltages or even use a webcam.For sending commands to the AC you can use the remote control.
Hacking gym elliptical - Page 1
Forum section: electronics / beginners

author: rthorntn
author_rank: Frequent Contributor
timestamp: December 17, 2019, 11:30:23 pm
content: Hi,I just picked up a discounted NordicTrack Elite 11.0 Elliptical on Ebay, I want to hack it.I would like to extract performance data and it would be great if I could control the elliptical to increase/decrease the intensity?I can see the elliptical has an ifit port, I think this takes an ifit module which adds wifi to the elliptical, I think this might tie me to the ifit app though which is bad, anyone hacked this or know anything about it, maybe it's a serial communications port?Maybe I can use bluetooth (might just be for heart rate), or even USB (might just be for phone charging), where do I even start?Ideally if I could hack something together without having to buy anything proprietary or be locked into monthly subscriptions then that would be fab, it doesn't need to be fancy.FWIW I'm pretty handy with computers and I can solder, I also have access to an oscilloscope.This looks interesting:https://github.com/dawsontoth/zwifithttps://github.com/jamesdotcuff/iFitControllerLooks like some people just remove the head unit and replace it with a SBC like RPi (and display) wired into the sensors, I probably don't want to go that far.I could buy the ifit module, they're going for around A$250 on ebay?The optimal result is I can get data from the elliptical, into one of these "games" where you can race up the side of a mountain.Thanks.Richard
Hacking software - Page 1
Forum section: electronics / beginners

author: FrankT
author_rank: Regular Contributor
timestamp: April 26, 2013, 12:01:53 am
content: After spending time capturing waveforms, hand converting them to bits, then to hex, then flipping the bit order, then flipping the byte order, I was wondering if there is software out there that does all of this?I ended up writing a perl script to convert the scope captured waveforms to binary.I then wrote a C++ windows program that displayed the data in binary and changed the colour of the bits that where changing in real time so I could see patterns.And now I'm capturing some FSK data, and viewing it in realterm, but the character set is 0-A, 1-B, 2-C, etc so I need to translate the data I am viewing.

author: codeboy2k
author_rank: Super Contributor
timestamp: April 26, 2013, 07:38:28 am
content: You won't be able to get away without any programming effort, but there are tools to manipulate, display and simulate with captured data and real-world connections, and make it somewhat easier to deal with.In the past I have used MATLAB and Simulink (http://www.mathworks.com/). Since I don't work for a big name company anymore, I don't have any license for it. So lately I've been using GNU Octave on Linux. It's mostly MATLAB compatible. There is also FreeMat (http://freemat.sourceforge.net/), and SciLab with XCOS simulator (http://www.scilab.org/), which I am not familiar with but I plan to look at too.As for your choice of Perl .... my god.. I know it's powerful, but it's so easy to shoot yourself in the foot, and with 9 ways to do the same thing... I just gave up on Perl years ago. And I know it well.. I was around when Larry Wall released it and it was magical back then. There are much better languages to use now.
HackRF sample_rate question - Page 1
Forum section: electronics / beginners

author: salviador
author_rank: Regular Contributor
timestamp: June 30, 2017, 10:08:34 am
content: I'm confused about the sample rate issue, Nyquist-Shannon says:"The minimum sampling frequency of That signal must be at least twice its maximum frequency"But in the example of hackrf the sample rate is Is lower than the frequency you want to receive, example the FM receiverWhy?

author: danadak
author_rank: Super Contributor
timestamp: June 30, 2017, 10:22:54 am
content: This might help -https://dspguru.com/dsp/faqs/multirate/decimation/Regards, Dana.

author: ataradov
author_rank: Super Contributor
timestamp: June 30, 2017, 03:48:36 pm
content: Not the maximum frequency, but the maximum bandwidth. You can sample 1 MHz band at 100 MHz central frequency with 2 MHz ADC and recover the signal (provided your filters are ideal of close). This is called undersampling, and this technique is often used in practice.This note is unrelated to Hack_RF, I don't know what they are doing there.In the bottom left box, you can see that they are interested in the 200 kHz bandwidth, so sampling it at 20 MHz is not a problem.
Had some issues with a trim pot and would like some input. - Page 1
Forum section: electronics / beginners

author: guitchess
author_rank: Regular Contributor
timestamp: January 01, 2014, 05:51:27 am
content: I recently built a guitar effects pedal. On this occasion, I wanted to try my hand at making a pcb instead of using perf board. I also decided to forego bread boarding the circuit as it has been built by many people since it is a very popular design. After completing the build, it would not work. After much troubleshooting and internet research, I found that the issue was that the trim pot was letting full voltage get to the jfet. It read 8.4 volts on all three pins. Of course, I removed the pot and it tested fine. I ended up getting the effect to work by installing the pot as a voltage divider. Pin 1 to ground. Pin 2 to the Drain of the FET. Pin 3 to voltage.Am I misunderstanding how the pot is connected in the schematic? Is there something else I doing wrong and using a voltage divider is just creating a work around?I have attached images of the original, my schematic, and my layout. Any and all input/advice/tips are appreciated.Thanks.

author: digsys
author_rank: Unknown
timestamp: January 01, 2014, 11:33:19 am
content: Fig2: I assume you mean R7 / Q5. Normally off, D will be at Vcc (8.4V), which is why you see Vcc on all 3 pins.I can't work out how they expect to drive Q5 in the linear region though, without any other biasing and being AC coupled?I'm sure you'll get better response when drunken NY members sober up :-)

author: ttp
author_rank: Regular Contributor
timestamp: January 01, 2014, 11:51:38 pm
content: Double check FET pinouts, I suspect you may have them wrong way around or FET is faulty. I would expect gate to be at 0V for a start, can't understand how are you getting 8.4V gate voltage in original circuit. Looking at DC circuit I would expect gate at 0V, some drain/source current causing voltage across R11 (approx. 0.4V to 0.8V) so the gate is negative relative to source.
Hager ER120 - what does it do? - Page 1
Forum section: electronics / beginners

author: endeavour
author_rank: Newbie
timestamp: April 09, 2024, 02:45:27 pm
content: I'm not sure I understand the wiring diagram on the front of the unit, nor what the switch is meant to do. Could anybody explain how it works?Also is the switch meant to move, because it seems to be stuck in the auto position?Thanks!

author: Manul
author_rank: Super Contributor
timestamp: April 09, 2024, 08:10:42 pm
content: Seems to be a relay with two pairs of contancs, NO (normally open) and NC (normally closed). Operated by energizing A1 and A2 with 230V AC. Switch is probably a manual override, for testing purposes, not sure.

author: tooki
author_rank: Super Contributor
timestamp: April 09, 2024, 08:32:15 pm
content: Manul is exactly right. The “auto” position is just the “normal” position (i.e. it operates as a relay controlled by the coil), while “on” and “off” manually override it.

author: MarkT
author_rank: Frequent Contributor
timestamp: April 09, 2024, 10:31:03 pm
content: I suspect its useful for maintenance/servicing of equipment as an override to the normal operating mode. Hopefully the lever is sprung to return to centre so you can't accidentally leave things overriden...

author: tooki
author_rank: Super Contributor
timestamp: April 09, 2024, 11:54:19 pm
content: Quote from: MarkT on April 09, 2024, 10:31:03 pmBased on their current catalog, I suspect the switch is specifically designed to stay on or off, which is the point of the switch: it’s an override.They make other models which return from on to auto, but manual off stays off.

author: endeavour
author_rank: Newbie
timestamp: April 10, 2024, 02:20:52 pm
content: Thanks all, that makes sense.
Hakko 700 B - is there anyway to hotwire the five pin the solder connection so the vacuum pump the w - Page 1
Forum section: electronics / beginners

author: Jfasig
author_rank: Newbie
timestamp: March 04, 2017, 12:38:02 am
content: Will work ,sorry first post don't beet me up to much ment desolder 5 pin connection, do not have cable or gun ,just wanted to use vac for desoldering occasionally,Thanks.Sent from my iPhone using Tapatalk
Hakko 703 rework station - Page 1
Forum section: electronics / beginners

author: JPM_AEIC
author_rank: Newbie
timestamp: October 28, 2018, 05:45:03 pm
content: I have the opportunity to buy a brand new Hakko 703 rework station. This would be my first big purchase, so I’m looking for more experienced replies as to 1) The quality of this unit, especially the desoldering vacuum pump. And 2) The difficulties of finding replacement parts for a discontinued product. Also, any other advice for a budding electronics engineer would be most welcome. Thanks!Sent from my iPhone using Tapatalk

author: helius
author_rank: Super Contributor
timestamp: October 28, 2018, 06:33:24 pm
content: It uses the same consumables/parts as the 928 and 472, which are either still available or compatible with newer parts. This generation of Hakko desoldering station used two types of vacuum source: a double-cylinder pump, and an air ejector. The air ejector requires a compressed air supply, while the pumps are electric. They have somewhat better vacuum performance compared with the hand-held 808/FR300 tools.You can use the newer N50 series vacuum tips with the 807 desoldering iron; the original A100x are not being manufactured anymore.The soldering iron and tips are widely cloned now, and available from both Hakko, and domestic and overseas second sources.
Hakko 808 owners - which parts need replacement most? - Page 1
Forum section: electronics / beginners

author: hurricanehenry
author_rank: Regular Contributor
timestamp: September 06, 2016, 12:27:15 am
content: Hi - I am interested to know from long time 808 owners which parts should I keep on hand to keep my 808 operational? I am not referring to the obvious parts like the filters, but maybe components of the pump mechanism, etc. I know Hakko still sells some replacement parts but I don't know which,and how many of them, to buy on hand.It concerns me that it's already discontinued as a model, so I want to keep parts on hand.Thanks!

author: RobertHolcombe
author_rank: Frequent Contributor
timestamp: September 06, 2016, 03:02:05 am
content: When I started working for my current employer they already owned two Hakko 808 but I don't know the history of them. Over approximately 3 years of daily use the motors died in both, and one heating element stopped working. In both cases the motor suddenly couldn't create vacuum pressure with any load, and I believe one of the wires broke off the heating element.We had a difficult time locating replacement parts in Australia so opted to buy a FR-300 to replace them since we needed a solution ASAP. I'd be interested to see if you are able to locate parts because we still have the two 808 sitting in a box

author: hurricanehenry
author_rank: Regular Contributor
timestamp: September 06, 2016, 09:51:47 pm
content: Thanks for the info.Doesn't Hakko sell parts for them?Well, maybe by now it's been so long, they don't.I have go to check.Looking forward to hearing from any other 808 users as well.

author: RobertHolcombe
author_rank: Frequent Contributor
timestamp: September 06, 2016, 10:01:21 pm
content: http://srt.co.th/Products/Import_Products/Hakko/accessories/808_PartsList.pdfPretty much the whole unit can be re-built its just a matter of finding a source of the parts

author: hurricanehenry
author_rank: Regular Contributor
timestamp: September 07, 2016, 03:16:42 am
content: Hakko has the same parts listings but the problem is that many of them are not actually available (backordered, possibly indefinitely).
Hakko 808.... Replace or Repair? - Page 1
Forum section: electronics / beginners

author: Mp3
author_rank: Frequent Contributor
timestamp: February 28, 2018, 10:47:37 pm
content: As some of you may know Hakko discontinued the 808 desoldering gun!!!well i didn't notice until i had to clean out both my filter capsules again that i should get some spare parts ready.... that's when i realize it's been discontinuedIt has worked pretty well for me, although i've never used any other desoldering tool besides a plain iron with a pump stuck on it like you might find at Radioshack.I am deciding whether i should sell it to someone who wants it while it still works, or stock up on repair parts and keep maintaining it.Does anyone have any ideas? If you had to desolder over 100 solder points in any given sitting you are doing repairs, is there another desoldering unit you might look to instead, those EEVbloggers who have more experience than I?

author: alpher
author_rank: Frequent Contributor
timestamp: March 01, 2018, 03:32:47 am
content: Just exactly what consumables are you having aproblems with?I have the same machine.

author: mcinque
author_rank: Unknown
timestamp: March 01, 2018, 07:18:09 am
content: AFAIK, 808 spare parts are available here.

author: Mp3
author_rank: Frequent Contributor
timestamp: March 03, 2018, 09:12:15 am
content: Quote from: alpher on March 01, 2018, 03:32:47 amI'm not sure, but it clogs frequently. I don't think my filters are bad.

author: mcinque
author_rank: Unknown
timestamp: March 04, 2018, 11:34:26 am
content: what clogs exactly? nozzle? tube nozzle? the filter? tell us more details. I can assure you it's a great tool and if it clogs there is a manteinance issue

author: beenosam
author_rank: Regular Contributor
timestamp: March 04, 2018, 01:06:44 pm
content: You should be able to repair it and fix your issue. There seems to still be a market for parts. But if you don't feel up to it, you can always sell it to someone who can fix it.

author: Slow Poke
author_rank: Contributor
timestamp: March 15, 2019, 04:35:19 pm
content: Answer to your desoldering prayers:https://www.hakkousa.com/products/desoldering/fr-301-desoldering-tool.html#tab6Other'n pretty colors how is this real-world better??
Hakko 808 resistor keeps blowing. - Page 1
Forum section: electronics / beginners

author: mictas
author_rank: Regular Contributor
timestamp: March 10, 2014, 02:36:42 am
content: Well I'll try and word this as best as I can, the desoldering gun at my local hacker space has blown for the second time now, one of the other member's walked through the diagnoses and replacement of the offending resistor.This rather large resistor and is connection to the mains voltage, after the trigger switch. And is not apart of the temp control board, it however is housed with one screw, almost under the motor, its self. The resistor is housed on a single layer PCD board with two other blue companions.Has anyone else had a hakko 808 where this resistor has blown more then once? And if so, is it one of those cases where its just crappy parts or a problem else where, along the line?

author: amyk
author_rank: Super Contributor
timestamp: March 10, 2014, 11:47:25 am
content: You may want to trace a schematic of the unit to make sure, but from its description it sounds like a current-limiting resistor for a transformerless supply - and if that's the case, the problem could be something pulling too much current through it.

author: mictas
author_rank: Regular Contributor
timestamp: March 11, 2014, 07:12:28 am
content: Quote from: amyk on March 10, 2014, 11:47:25 amOkay, reading this, I really should get a third party to also take a poke at this.Thanks for that, I'll keep it in mind the next time we all meet up.

author: granz
author_rank: Regular Contributor
timestamp: March 11, 2014, 02:13:40 pm
content: Be sure that you have the right heater element. There is apparently a 110V version and a 220V version. If you have the 110V version and you are running it on 220V you could be drawing way too much current.

author: mictas
author_rank: Regular Contributor
timestamp: March 11, 2014, 09:45:15 pm
content: Quote from: granz on March 11, 2014, 02:13:40 pmWell I do not know if the element was replaced, but this is a 220v Australian model and not the US version, I'll have to ask the owner to see what was fixed last time.Thanks.