hybridfree/eevblog-posts huggingface dataset:
Expert for the USB Protocol here? - Page 1
Forum section: electronics / projects

author: Lord of nothing
author_rank: Super Contributor
timestamp: July 17, 2023, 12:44:53 pm
content: Hi everyone!Well many years ago I bought an normal Glasfiber Media Converter to Galvanic separate the Network in each Floor. And the where cheap also... Well I got caught in a Problem I never tough about. My 1000Mb Media Converter did not work with an 100Mb Switch.Ok ok I bought an 1000Mb Switch and problem solved... So today I saw a new Product from my favourite German Chinese Product Import Company called "Delock". It is not an ad for the Company but I bought a lot of stuff truth your IT Distributor since the have the weird stuff anyone normally find then only on Aliexpress fresh out of the Chinese Product Line.Yesterday I saw the have an USB over Glasfiber Device.Minutes ago I got an offer from my IT Distributor and the price is good in comparison with other Brand Products like Icron who I payed +1000€ for there hight quality USB over Glasfiber Product. (To name other Company to). The only think with the Delock is the claim it support only USB 3.0 and not 2.0, 1.1.https://www.delock.de/produkt/66466/merkmale.html?f=nSo... can someone explain why? What could be the reason? How about an USB 3.0 Hub connect to the Adapter does there I can put some USB 2.0 stuff on?In my case I want, need connect my HackRF to my Server:https://greatscottgadgets.com/hackrf/one/And no rout a Antenna Cable would be insane do to the loss.Thanks!

author: DavidAlfa
author_rank: Super Contributor
timestamp: July 17, 2023, 01:09:18 pm
content: Some reading and possible workaround:https://hackaday.com/2022/03/07/a-chip-to-address-the-fundamental-usb-3-0-deficiency/

author: Lord of nothing
author_rank: Super Contributor
timestamp: July 17, 2023, 01:54:10 pm
content: Sounds good! Where can I get the finish borad from?What happen when I plug in an USB Hub before the Module?I also must mount them Bug proffe.

author: DavidAlfa
author_rank: Super Contributor
timestamp: July 17, 2023, 03:27:29 pm
content: I can't tell. As far as I know VIA seems the only one doing so.Everything can be found here, perhabs you could ask him if he has any spare board.https://notabug.org/niconiconi/vl670/src/main
Expiriance with components from LCSC.(com) - Page 1
Forum section: electronics / projects

author: jonsig
author_rank: Contributor
timestamp: July 31, 2022, 02:18:34 pm
content: Good day fellow members, i have lots to ask about. Using my 3rd language, so i hope you can bear with meTo make long story .. shorter.I have been restocking solid capacitors from random manufacturers from this site and some electrolyte caps with impressive ? specs like samxon GT series (7000hrs), Ymin(10000hrs)and Aishi (3000hrs) in correct physical dimensions i´m having problem finding on mouser/TME. Also bought lots of >650V rated semiconductors, mosfets etc and diodes.So far i´m really happy with the service and LCSC answer all of my questions asap with followup. And the accessory i´ve bought from them looks top notch at least not inferior to mouser/tme. for example THT soldering pcb´s, alcahol dispensers etc.But i´m wondering if i´m shooting my self in the foot with this. In my work we use rubycon,nichicon and panasonic religiusly even for low demanding applications but that´s for demanding customers who pay whatever is needed.Guess i trust reputable brands like Aishi and Samxon for i know Ikea and even apple are sourcing capacitors from them.I dont know about this Ymin even they have impressive specs and the look and feel like real thing.All of the solid caps from random manufacturers on the site i have tested show very good consistancy in both capacitance and ESR off the shelf. But how long they will last i dont have a clue nor expirience.Almost everything i google about those brands i mostly see disbanded right away by fanatics with some personal agenda against some capacitor manufacturers ? And just being Chinese, even if people are asking how particular brand from taiwan is holding up like elite or teapo.But those purchases are intended for "hobby" use. I´m mostly reparing SMPS devices at the moment which end up donated or sold for fair price, so unnecessary spending on premium parts for religios reasons is not always smart, but i like to strike some balance to reliabilty to maintain my reputation to customers and charity groups.Do LCSC avoid bad manufacturers with strict quality policy and feedback from customers ? should i stick to particular brand they sell ? or is this just plain bad idea ?best regards

author: Vovk_Z
author_rank: Super Contributor
timestamp: August 01, 2022, 08:27:26 pm
content: One of my sub-hobbies is repairing ATX power supplies, and I have bought different solid polymer caps from LCSC and all of them are fine yet.I have bought IRFP250 they are fine too.
Explanation for LT1970 based V/I control block - Page 1
Forum section: electronics / projects

author: axitece
author_rank: Contributor
timestamp: April 02, 2017, 04:13:30 pm
content: I've come across a circuit in the architecture document for NI's PXI 4110 programmable power supply that I was hoping someone could help me understand. The V/I control block for the power supply's linear stage is designed around Linear Technology's LT1970 power amplifier which is capable of supplying up to 500 mA. However, since the power supply needs to source up to 1A, the engineers at NI designed an analog "translator" circuit. The circuit for the V/I control block can be seen in the attached image. Any kind of help in understanding the operation of this circuit is greatly appreciated. Thanks!

author: Kleinstein
author_rank: Super Contributor
timestamp: April 02, 2017, 05:01:58 pm
content: The extra p-Channel MOSFET and transistor circuit it there to provide an extra current boost. This path is providing essentially all the output current.Under normal operation the LT1970 is sinking a current of about 22 mA, so just enough to bring the extern NPN and the P-MOSFET in linear operation. More current through the V- pin of the OP leads to less current through the NPN and thus less gate voltage and current for the P-MOSFET.For fast signal components the OPs output can also sink and maybe even source extra current. To a limited extend (sinking about 5 mA) this circuit can go 4 quadrants.The divider with 1 K and 200 Ohms gives a first approximation feedback, the other 75 K /25 K divider to the inverting input gives the main DC feedback. There is no active current limit in this circuit.With the fast voltage feedback via the 100 nF capacitor to the OPs output, I am not sure this circuit is really stable with an low ESR capacitor at the output.
Explanation for Transmit circuit - Page 1
Forum section: electronics / projects

author: SScattered
author_rank: Contributor
timestamp: July 11, 2024, 06:04:22 am
content: Please refer to the transmit circuit in thishttp://blog.svenbrauch.de/2017/02/19/homemade-10-mbits-laser-optical-ethernet-transceiver/I've gone through it's explanation in the website. But I'm still not sure how does it just change the brightness of the laser. I want to achieve the same thing but using an IO from a microcontroller as the input instead of Tx+ and Tx-I'm an electrical engineer but not much focused on electronics. Any help would be appreciated.

author: mikerj
author_rank: Super Contributor
timestamp: July 11, 2024, 08:10:33 am
content: TX+ and TX- are to apply a modulation signal to the laser (i.e. data signal), not to control brightness. The inductors L1 and L3 and capacitor C10 allow the modulation current to pass through the laser without being loaded by, or disturbing the rest of the circuit. If there were not in place the low impedance of the op-amp output and R5 would present a high load to the circuit driving TX+/-.The rest of the circuit is a basic constant current source, with the current being set by RV1. The op-amp compares the voltage on it's inverting and non-inverting inputs and changes it's output voltage to try to balance them. The inverting input comes from resistor R5 (10 ohm) which has the full laser current passing through it, causing a voltage drop as per Ohm law, so the op-amp is trying to keep this voltage the same as on the wiper of RV1, and hence keeping the LED current constant.C8, R4 and R7 are compensation components to keep the circuit stable. R7 provides a bit of isolation from capacitor C10, most op-amps do not like driving a strongly capacitive load. With all the inductance in the laser current path there will be considerable phase shifts that would make this circuit oscillate, so C8 and R4 allow AC feedback directly from the output of the op-amp to "override" the AC component across R5.It's not clear if you want your micro to modulate the LED or control the average output power. To modulate it you need to apply a differential modulation current to TX+/-, and since this is AC coupled by C7/C23 there is a lower bound on the modulation frequency that you can use. Since this circuit is designed to be driven via an ethernet signal, you could just hook up an ethernet transformer to TX+/- and drive the other side from a pin on your micro.If you want to control the laser current (i.e. brightness) from the micro you can simply have it drive a suitable voltage into the non-inverting terminal of the op-amp instead of RV1. This could be from a DAC or using well filtered PWM.

author: SScattered
author_rank: Contributor
timestamp: July 11, 2024, 09:32:43 am
content: Quote from: mikerj on July 11, 2024, 08:10:33 amThank you very much! I understand now. Yes, my concern was to use this to modulate using data from a microcontroller, like serial data. I think now I have a lead from your advice, I will try looking into a ethernet transformer.
Explanation of how kilowatt-hour meters work (electromechanical)  - Page 1
Forum section: electronics / projects

author: xrunner
author_rank: Super Contributor
timestamp: October 10, 2013, 11:50:58 am
content: Nope, no microcontrollers in this baby. No transistors or logic gates. If you're looking for that, this video ain't your cup of tea.But interesting how they used basic electrical and magnetic theory to make the instrument.

author: JoeyP
author_rank: Frequent Contributor
timestamp: October 10, 2013, 06:58:11 pm
content: That was interesting. I'd always wondered what they used to provide a predictable source of resistance to the force generated by the varying magnetic field. Clever to use permanent magnets and associated eddy current related force, since they would stay relatively constant over a long period of time. Also interesting about the couple of hacks they use to account for friction at very low power levels.At one time in my early youth, I had a job rebuilding gas meters - the type you have outside your house metering your gas service. They are basically very similar to a steam engine driven by gas moving through the pipes. They (at that time) used leather bellows instead of cylinders. BTW, they virtually always slow down with age, which gives the customer a better and better deal over time. Moral of the story - never complain to the gas company that your meter is not accurate unless you're absolutely sure of it. They will replace it with a freshly overhauled and calibrated unit, and your bill will likely go up!

author: SeanB
author_rank: Super Contributor
timestamp: October 10, 2013, 07:46:39 pm
content: Had the same with the bulk water meter, did not want to roll over to all zeros until I did a little percussive maintenance on it while it was at full flow ( opened the 2 fire hose standpipes to full to get there) and used a 4 lb hammer to gently tap the housing to jar it loose. Did not want it replaced as it was worn nicely and had a little droop, plus the metro wanted us to pay the costs of the new meter and the installation as well.There was one garage with a similar fault in the one pump, I filled my tank slowly ( blocked breather pipe) and found that a full tank was 15l of fuel as opposed to 45. Next day I called the head office and spoke to the technical manager and about a week later the whole pump was replaced. they are calibrated at a high flow rate, so the wear on the positive displacement pump is not noticed during the testing with a calibrated volume tank they use.
Explanation of valves, crystal sets and stuff - Page 1
Forum section: electronics / projects

author: vk3yedotcom
author_rank: Frequent Contributor
timestamp: August 28, 2012, 01:06:18 pm
content: Even if you're not into valves, this video contains one of the best explanations I've seenIt's part of a series to do with crystal sets. I like how he explains and then demonstrates, showing what happens. Plus good use of graphics for the valve part.

author: phil_jp1
author_rank: Regular Contributor
timestamp: August 29, 2012, 11:25:27 am
content: Very nice video! Thank you for posting it here!I wanted to experiment with valves for quite some time. Maybe I will soon.. just need to get some valves.

author: steve30
author_rank: Frequent Contributor
timestamp: August 29, 2012, 10:10:34 pm
content: He explains this very well.I dabbled with crystal and transistor radio circuits a few years ago, in fact, I still have a simple transistor radio built up on a breadboard.I'd like to have a play with valves sometime though.
Exploding Verizon Hot Spots (they're hot!) - Page 1
Forum section: electronics / projects

author: Renate
author_rank: Super Contributor
timestamp: August 23, 2021, 08:20:19 pm
content: I just did a recall for a Verizon "Ellipse" (by Franklin) hot spot.Apparently there has been problems with the LiPo overcharging and exploding/burning.They sent me a new Verizon "Orbic Speed" (by Inseego) as a replacement (which I haven't unpacked yet).I had already noticed that my old "Ellipse" overcharged and got hot, so I had already removed the battery and did a USB battery replacement.I also noticed that even the processor got hot and the sensitivity to marginal signal decreased.So I removed and threw away all the unnecessary plastic (read "insulation") and put a little fan on it.So when they recalled that, I bought the "top of the line"  8800L (by Inseego).That likes to overcharge the battery too and think that disconnecting from power is your responsibility.Sorry, this is a 24/7 device and I'm not going to go unplugging and plugging it all day long.It got to a zillion degrees hot one day and decided to shut down.So, once again, I stripped the superfluous plastic (but not the antennas), put in a diode for the drop, a 51k for the ID and 100k for the thermistor.We'll see how that does, but it seems to be working fine.Wow, that's a crummy photo.Edit: Well, I really got sick of how hot it was so, I ripped out the glass/touchscreen from the front bezel and removed the OLED that blocks the processor from the breeze.Now it's headless, but cooler.Does this void my warranty?More edit: Wow, removing the glass was a total win.I can touch the tin shield of the processor and barely detect some warmth.Keeping it cool really does help the S/NR.Yes, I did clean up the wiring nicely with heatshrink and everything.The cord goes through a hole in the case that's as far away as possible to all the antennas.
ExpressCard/54 shield supplier? - Page 1
Forum section: electronics / projects

author: joshtyler
author_rank: Contributor
timestamp: August 23, 2017, 10:40:41 pm
content: I'm planning a project which will use the ExpressCard/54 form factor (Yes, I know ExpressCard is long dead but I want to use it for this).Does anyone know anywhere where I can buy the metal shield/enclosure for the card? The only one I can find was made by Amphenol, and seems to be exactly what I want (top,bottom), but it's now obsolete, and nowhere has any stock.Any idea where I can source something like this today? If there is nothing about I'll just have to buy a cheap USB hub module from AliExpress and reuse the shield from that.
EXT. SYNC'ed   20 - LED Light Chaser / or phased Audio Gen. Clock - Page 1
Forum section: electronics / projects

author: RJSV
author_rank: Super Contributor
timestamp: January 25, 2019, 10:51:13 pm
content: Two feature rich counter IC's are combined as a pair with 20 outputs. A 'RANGE' latch coordinates two CD-4017 Decade Counters, as low-high digits (oX and 1X). A 20 LED 'Knight Rider' light chaser operates very similar to commonly seen circuits having ten outputs / LED's.An external RESET places the 20-step 'moving dot' circuit into phase (counter re-starts at zero count).For operating / clocking various audio waveform generators, a circuit input clock speed is set at 8800 hz, to be divided down, before output as pulses / square waves, as connected by the CD-4017 sequencer outputs. Don't forget, the counter IC's are low power, and so better used with a transistor or other buffer for providing perhaps 5 mA, more if you use an 'inverted' scheme (moving dark place, against all other LED's turned on.Mistake on a gate: That NAND gate shown (lower left corner of schematic), that mixes the EXT reset, that gate should be 'NOR', as it mixes two -P signals. Also, looking above to the IC3b clock, the inverter should not be there, as want the end of each of the pulses, Q02 and Q12.(that RANGE PREVIEW signal is used to de-glitch the two LED's on the Q0 outputs, as there can be a brief phantom flash, as waiting for the RANGE ff to toggle to proper range.) thanks
extending Arduino functionality - Page 1
Forum section: electronics / projects

author: Embeddio
author_rank: Newbie
timestamp: May 19, 2020, 05:10:12 pm
content: Add Functionality To Your Development Board (Arduino, Raspberry Pi, etc.) - Only One In The World Providing These Kinds OfUniqueBoards!https://www.kickstarter.com/projects/embeddio/snap-boards-snap-to-the-future- Snap them on top of each other anduse them simultaneously(I2C capabilities, pull-up resistors optional) to code faster!-Actually being able to access important pinsfor debugging purposes (e.g. SDA and SCL)- Snap the module, with castellations and small footprint, out of the board and use it foryour custom circuit board!- Available indifferent colors
Extending Capabilities of an Electronic Load - Advice Wanted - Page 1
Forum section: electronics / projects

author: Katalyst
author_rank: Newbie
timestamp: November 08, 2012, 04:46:02 pm
content: Hello EEVbloggers,I have come to you for suggestionsI am working on a design to hook a generator up to an electronic load to burn energy for testing purposes.Technical details of both partsElectronic Load: BK Precision 8502 - 300W - 500V - 15AGenerator: Ginlong GL-PMG-3500 (http://goo.gl/mFnC0) - 1500W - 275V (approx. @150RPM)I want to connect high power and high resistance resistors in series between the generator and the load to choke voltage and bring it down to a managable level (around 50V) because I want to control the current using the load. I will use an appropriate thermal setup to dissipate the heat from the resistors. I am not worried about this. What I am curious about is the capabilities of the electronic load. Are there any problems that you can foresee which perhaps I am overlooking?Thanks for your help!!Katalyst
extension speaker with multiple inputs - Page 1
Forum section: electronics / projects

author: Flump
author_rank: Frequent Contributor
timestamp: November 06, 2015, 12:16:36 am
content: I have 3 ham radios on at the same time and have separate extension speakers for them,I would like to have 1 speaker that I can plug in to the 3 radios and maybe have a spare leadfor radios I am testing/working on.I don't want a speaker/source switcher as the radios will be on at the same time so i need to combinethe audio signals so they feed the speaker all at the same time.Any suggestions on ways to do this would be great.(the speaker is not amplified)

author: commongrounder
author_rank: Frequent Contributor
timestamp: November 06, 2015, 03:22:22 pm
content: Without specifications for the radios, I can only speak in general terms. Wiring dissimilar (radio) amplifier outputs in parallel is not a good idea, especially if they are not carrying the same signal. Each amplifier will see the other amplifiers outputs as a very low impedance load and will behave as though they are driving close to a short circuit (i.e. damage may occur). The quick and dirty way to mix amp outputs in a situation like this is to insert series resistors in each radio line feeding the speaker. These could be four to eight ohm, at a few watts, each. This would isolate the amps from each other and give each amp a load it can handle. The down side to this is at least half of each of your radio's amplifier power will be dumped as heat from the resistors (i.e. wasted). This may not be a real problem if your extension speaker is very efficient.Another solution might involve using a powered speaker (which would be the best idea, actually) and a passive, or active, audio mixer. With this system you could use the record outputs on the receivers as audio feeds. More equipment needed, though, and it sounds like you are trying to keep it simple.
External battery charging port safety off. - Page 1
Forum section: electronics / projects

author: MikeLemon
author_rank: Contributor
timestamp: March 02, 2018, 11:59:54 am
content: Hello,Some of my project require a charging port out that is connected directly to the main battery and I'm concerned with that sins some metal objects may simply short the battery out directly by accident or something so I started working on some protection circuit for that and found out there might be a potential for that to also be a reverse polarity protection circuit but came across some problems here is the schematic:I'm concerned with both sides of the circuit being live.What could be the solution for such a thing?Thanks for helping.

author: Zero999
author_rank: Super Contributor
timestamp: March 02, 2018, 09:23:46 pm
content: That's the standard MOSFET reverse polarity protection circuit.It should prevent the battery voltage from appearing on the connector, but how do you ensure the battery is properly recharged? Normally the battery charger is built-into the equipment and the external power supply just provides a constant voltage.

author: MikeLemon
author_rank: Contributor
timestamp: March 03, 2018, 07:47:14 am
content: Ok so, you say if I connect this circuit everything would go as expected?And I ensure the battery is properly charged by having a BMS constantly connected to it with the balance ports and a standard 10S li ion charger but you said something interesting, you said those chargers only provide constant voltage? just like any other regulator?I'm looking for a solution to be able to maybe design it my self but I realy don't understand how complicated or expensive that would be.say I want to charge a 10S battery with another 10S battery. How'd I do it?

author: plazma
author_rank: Frequent Contributor
timestamp: March 03, 2018, 09:05:22 am
content: This is a circuit I designed for a divelight charging port. The TVS diode and ferrites are for ESD protection.

author: MikeLemon
author_rank: Contributor
timestamp: March 03, 2018, 10:47:55 am
content: Hi,Looks good but seems like it takes too many components for such a simple task wouldn't be possible to do what I mentioned with a single transistor?What's the explanation for having so many FETs?Thanks in advance.

author: plazma
author_rank: Frequent Contributor
timestamp: March 03, 2018, 12:04:38 pm
content: You can buy the FETs in double package. The FETs are in pairs so they don't leak through the intrinsic diode. So skipping the ESD protection you only need two double FET packages and four resistors.

author: MikeLemon
author_rank: Contributor
timestamp: March 03, 2018, 12:52:33 pm
content: Ok...Thinking about it the max current should be around 6A but what fets do you recommend for these kinds of current at around 20V?Also why not use a single one again?
External e-bike battery information on reverse current handling - Page 1
Forum section: electronics / projects

author: kcsaba
author_rank: Newbie
timestamp: June 17, 2019, 10:23:29 pm
content: Hi dear community!I have an electric scooter (xiaomi mi 365), and i would like to extend it's range. I thought of external e-bike batteries,because they have a case and a charger, so i could just switch between the original and the external battery when needed.The only problem i have is that i can't seem to find a pack that has a correct datasheet, from which i would be able to know if it can handle reverse current on the discharge port. Because my scooter does regenerative braking, and it would supply current backwards on the discharge port when i brake.So can you please advise me what to do, how to solve this?I would like to solve this the easiest way possible.(I know of solutions that are common, e.g. firmware patching, or just putting the battery paralell, but i think they are nasty, and would like to avoid them.)Thank you!

author: NiHaoMike
author_rank: Super Contributor
timestamp: June 17, 2019, 11:26:47 pm
content: Just connecting the batteries in parallel is fine as long as you let them equalize voltage first by leaving them connected through some resistance (e.g. an incandescent light bulb) until they're more or less the same voltage.

author: MosherIV
author_rank: Super Contributor
timestamp: June 18, 2019, 06:55:32 am
content: Look at the charge specifications for regenerative braking. It is after all an instant change from discharge to charge.The battery pack BMS should really handle this.One tricky scenario is what happens when the battery is 100% SOC (full) and you go down a hill and you use regen braking ?In a car (or lorry in my case) where does the charge current go? (Not into the battery, that would be very bad)

author: NiHaoMike
author_rank: Super Contributor
timestamp: June 18, 2019, 02:12:45 pm
content: Quote from: MosherIV on June 18, 2019, 06:55:32 amThe actual charge level at "100%" should be more like 80% in order to extend lifetime. Also not that difficult to adjust charge level based on altitude.In a car, one way to burn up excess energy is to run the heater and A/C at the same time. On a bike, I suppose you could turn on the headlight?
External microphone mod for SONY A5100 - Page 1
Forum section: electronics / projects

author: naftaliin
author_rank: Newbie
timestamp: May 18, 2016, 06:39:47 pm
content: Hello!The SONY A5100 is a good camera for the price but it lacks external microphone input.http://www.sony.com/electronics/interchangeable-lens-cameras/ilce-5100-body-kitI am thinking of buying this camera but only if I could modify it to support external microphones.Has anybody done a tear-down of this camera? It looks very compact and I wonder whether there is going to be room inside to add an audio input jack.People have done this mod for other cameras.These however were mirrored cameras and of slightly larger size. Sony A5100 is mirroreless and more compact.Open to opinions and suggestions also.
External Monitor for digital oscilloscope - Page 1
Forum section: electronics / projects

author: Rayonger
author_rank: Newbie
timestamp: November 14, 2014, 06:23:29 pm
content: Gidday Aye:Trying to make out four channels on a 7" LCD is tedious and not much better on a bigger 10".Some Tektronic models have provision for using an external monitor. I am wondering if anyone has attempted a hardware modification to add a video card + resolution increase to any other midrange type of scope like atten, rigol, siglent...whatever. If so, give us a map of the traps.ThanksAll the bestRayonger

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: November 15, 2014, 08:39:02 pm
content: Maybe the easiest way to solve that is to point a camera at the screen and display it on a bigger monitor.

author: miguelvp
author_rank: Super Contributor
timestamp: November 15, 2014, 08:45:21 pm
content: I believe some low end scopes come with a vga output, owon at least do have them other than that it's going to take some serious hackingmaybe a good optical quality fresnel lens? but it might distort the image a lot not sure
External power for PCI Express card - Page 1
Forum section: electronics / projects

author: dkasza
author_rank: Newbie
timestamp: December 06, 2013, 03:07:40 am
content: Hello everyone,I just got a board that is too long to fit in my computer (it extends in the wrong direction), but has an ordinary PCI-Express x4 connector. I do not care about the data on this connector. The board has a few FPGAs on it that I intend to reprogram and not use the PCI-Express.Is there any simple and inexpensive solution to power a PCI-Express card outside a computer?The board has 4 LTM4600EV devices on the +12V rail, and it has diagnostic LEDs for 5 voltages including +12V, so it is quite possible that the board only needs the +12V and ground pins to be connected, but I could not verify that yet. In that case I could probably just solder leads to these pins and power it from a 12V supply. Still, I would prefer a nicer solution.Thanks!

author: Stonent
author_rank: Super Contributor
timestamp: December 06, 2013, 03:18:23 am
content: Might work for you:https://www.google.com/search?site=&tbm=isch&source=hp&biw=1280&bih=907&q=powered+pcie+riser&oq=powered+pci&gs_l=img.3.0.0i24l4.505.2015.0.3568.11.8.0.2.2.0.114.723.5j3.8.0....0...1ac.1.32.img..2.9.632.tMpkrsF7fQ8#imgdii=_

author: mariush
author_rank: Super Contributor
timestamp: December 06, 2013, 03:22:06 am
content: You can buy pci express female connectors and they're not expensive:http://www.digikey.com/product-detail/en/10018784-10201TLF/609-2026-ND/1002341http://www.digikey.com/product-detail/en/10018783-10201TLF/609-1978-ND/1002293http://www.digikey.com/product-detail/en/10018783-10011TLF/609-1965-ND/1002280etc etcYou can solder wires to the correct pins and be done with it:http://en.wikipedia.org/wiki/PCI_Express#Pinout

author: NiHaoMike
author_rank: Super Contributor
timestamp: December 06, 2013, 05:59:48 am
content: Or you can get a dead or long obsolete motherboard and take the connector from it.

author: dkasza
author_rank: Newbie
timestamp: December 08, 2013, 12:15:34 am
content: Thank you all! Just to be safe, I ended up getting an ExpressCard -> PCI-Express adapter. I wanted to get one of these for a long time anyway. Once I get the board to work with this, I will design a less expensive board to power it.
external watchdog using NE555 - Page 1
Forum section: electronics / projects

author: derakhshanPazhuhesh
author_rank: Newbie
timestamp: November 23, 2024, 07:18:12 am
content: Hey therethe following circuit is a pulse missing detector, I want to use a RMT signal output from a ESP32 GPIO to feed the input of this circuit, thereafter, when the microcontroller is stopped working the circuit send a low voltage level to EN pin and so the microcontroller got reset, but the issue here is while the boot up, the voltage level shall be high so the boot happens but the output of the circuit without input signal is always down and stop micro from boot up, is there any solution to it?

author: KerimF
author_rank: Frequent Contributor
timestamp: November 23, 2024, 08:11:16 am
content: At boot, you may need to turn on T1 for a short time (how long depends on your code). This could be done by adding a resistor and a capacitor (connected in series) between the supply voltage and the transistor base. The resistance value could be 10K. You will need to choose the value of the capacitor to keep the MCU enabled till the GPIO starts enabling it.

author: KerimF
author_rank: Frequent Contributor
timestamp: November 23, 2024, 08:35:01 am
content: I noticed that the NE555 is supplied with 12V. Its output is therefore close to 12-1.4 = 10.6 V (12-1,4 = 10,6 V, in French)!I guess your actual supply is 5V instead of 12V, right?

author: derakhshanPazhuhesh
author_rank: Newbie
timestamp: November 23, 2024, 08:45:18 am
content: yes, I am using 5 volt and not 12 volts, actually the MCU is working with 3.3 volts, I will add a voltage divider or something at the output, but I didn't get idea of the resistor and capacitor in series with the base of Transistor, can you elaborate it or give a schematic maybe

author: xvr
author_rank: Frequent Contributor
timestamp: November 25, 2024, 05:00:07 pm
content: ESP32 has internal watchdog. Why you not use it?

author: PGPG
author_rank: Frequent Contributor
timestamp: November 25, 2024, 07:22:18 pm
content: Quote from: derakhshanPazhuhesh on November 23, 2024, 07:18:12 amFor me this circuit looks like positive pulse missing detector, but not negative pulse missing detector. So if microprocessor is stopped working with this output set positive than missing pulses will not be detected.
External wireless front door guest presence sensor to sounder alert - Page 1
Forum section: electronics / projects

author: mp
author_rank: Newbie
timestamp: July 06, 2020, 03:03:22 pm
content: Anyone know if there are any narrow angle, short distance, thermally stable wireless sensors available to use externally directly in front of a front door?The application is to activate a loud sounder when a courier or guest has reached the front door without them having to use the doorbell.I tried creating this with a PIR sensor however there were too many false alarms due to outside heat variations and individuals close by despite using black tape on the PIR sensor.

author: phil from seattle
author_rank: Super Contributor
timestamp: July 06, 2020, 05:38:08 pm
content: Try a Lidar sensor. Expensive though there are modules in the 50ish USD range. Maybe ultrasonic sensors? This one looks easy to use.https://www.sparkfun.com/products/15776

author: Whales
author_rank: Super Contributor
timestamp: August 04, 2020, 08:10:32 am
content: Automatic doors use "microwave motion detectors" for this situation.Not sure of pre-made options that come with wireless comms and battery, however. Generally speaking: most active sensing methods require something more than batteries if you don't want it to be a PITA.

author: nfmax
author_rank: Super Contributor
timestamp: August 04, 2020, 08:11:35 am
content: You can get little 5GHz doppler radar modules designed to operate a relay for automatic light switching: on the ones I have, you can disable the light sensor, so it will detect any motion. The sensitivity and 'on' period are also adjustable. They will 'see' through a wooden door quite easily, so can be mounted inside. They came installed in some Osram automatic LED luminaires. I have these set up in pairs, so a couple of the modules were surplus. I set up one to turn on the light in the front porch when someone approaches, though it occasionally gets triggered by by large vehicles (horse boxes!) passing in the road. The other one is in a box somewhere. I can't remember the manufacturer name though, it wasn't Osram.

author: cv007
author_rank: Frequent Contributor
timestamp: August 04, 2020, 09:45:01 am
content: Search for RCWL-0516.There is quite a bit of info out there on this thing, so should be easy to figure out if its suitable. Or spend $5 to find out. I do have some of them, although have not tested them yet.
Extra conductors in cable - ground or NC? - Page 1
Forum section: electronics / projects

author: shadewind
author_rank: Frequent Contributor
timestamp: August 24, 2012, 10:54:13 pm
content: I'm connecting two boards together through a connector with 8 conductors but I only need 7. Should I make the extra connector an extra ground or should I just leave it unconnected?

author: Rerouter
author_rank: Super Contributor
timestamp: August 24, 2012, 11:03:54 pm
content: make it a ground, it will help suck up a little bit more of the noise in your signals

author: Psi
author_rank: Super Contributor
timestamp: August 25, 2012, 01:38:08 am
content: Yes, make it ground. Less resistance in the ground path can only be good for you.Tie them to ground at both ends.Or, if you actually want separate grounds, be sure you check out which is best to use for what. eg, high current ground vs signal ground.You want the ground conductor with the least resistance to be used for power ground, which is often the mesh screen.However you also might want the mesh screen to be signal ground to screen all the other conductors.So you need to think about how you want to do it.

author: SeanB
author_rank: Super Contributor
timestamp: August 25, 2012, 05:08:23 am
content: If you do not use it use as ground, and preferably haveit next to the other, reduces the loop area to pick up common mode current. If you have a high frequency signal set use alternate conductors as ground with them.

author: EEMarc
author_rank: Regular Contributor
timestamp: August 25, 2012, 05:36:11 am
content: Using more than one conductor in a cable as ground is okay if they are terminated together at both ends.There is a hazard for ground loops for other configurations. Particularly for multiple cables that don't terminate in the same location on the board.The key for ground loops is the area of the loop of wire. The larger the loop, the easier it is to introduce a loop current. The more loop current, the larger the voltage difference at various points of the loop. If you have multiple cables, there is both the potential of a larger ground loop current and the voltage difference at different points in the circuit can cause havoc. Thus a ground loop problem. In the same cable, the loop is small. Even if it wasn't, the termination at both ends of the cable limits the effect of a ground loop current.As SeanB mentioned, minimize the loop area. Also, if you have a high speed differential signal, keep the pair adjacent and twist the pair if possible.

author: AndyC_772
author_rank: Super Contributor
timestamp: August 25, 2012, 07:48:51 am
content: What are the two boards, and what kinds of signals are the other 7 wires carrying?

author: shadewind
author_rank: Frequent Contributor
timestamp: August 27, 2012, 11:17:56 pm
content: I've made a Nixie driver board which drives two Nixie tubes. It has edge mounted horizontal headers so that you can place multiple ones edge to edge to daisy chain them without any cables. There will be a ribbon cable from the first board in the chain going to the board which controls the whole thing.
Extra dot on seven-segment display? - Page 1
Forum section: electronics / projects

author: radar_macgyver
author_rank: Frequent Contributor
timestamp: May 23, 2020, 06:58:39 pm
content: I have a fewLite-on LTC-4727JRseven-segment displays with four digits, four decimal points, a colon and a mysterious extra dot (marked L3 in the data sheet). Anyone know what the extra dot is for?

author: chriva
author_rank: Regular Contributor
timestamp: May 23, 2020, 07:03:41 pm
content: Degrees most likelyEver noticed the circle next to C and F?

author: WattsThat
author_rank: Frequent Contributor
timestamp: May 23, 2020, 07:08:15 pm
content: Agree, it’s degrees. It’s a multi-purpose clock display. Bog standard stuff.

author: radar_macgyver
author_rank: Frequent Contributor
timestamp: May 23, 2020, 07:43:48 pm
content: Makes sense, thanks!

author: Doctorandus_P
author_rank: Super Contributor
timestamp: May 26, 2020, 05:51:35 pm
content: This used to be done by putting the rightmost display upside down.
extract positive voltage to read adc - Page 1
Forum section: electronics / projects

author: electros6
author_rank: Regular Contributor
timestamp: July 28, 2015, 02:23:38 pm
content: HI guys,I have a circuit that using opamp using dual supply +- 5v. I want to read the output of the opamp using adc . since the opamp swings between the positive and negative rail ,please give any idea to built a circuit that allow positive voltage and block negative voltage.

author: fcb
author_rank: Super Contributor
timestamp: July 28, 2015, 03:05:12 pm
content: Diode....Or perhaps you'd get a better response if you describe your circuit in more detail, what the opamp is doing, what signal you are processing, etc... maybe a sketch as well.

author: electros6
author_rank: Regular Contributor
timestamp: July 28, 2015, 05:11:39 pm
content: I just try to measure the intensity of the light, so I used the photodiode and current to voltage converter and an inverting amplifier and an offset adjusting stage. schematic attached

author: Jeroen3
author_rank: Super Contributor
timestamp: July 28, 2015, 06:18:02 pm
content: "Convert" the +-15 Volts to 0-30Volts by putting your adc measurement circuit ground at -15 instead of 0v. Simple right?Power the ADC from +15 and -15, this indeed requires some ldo or smps depending on the load. Add an amplifier with gain of 1/5, assuming the ADC is 5V. And you're almost done.You'll still need anti-aliasing filtering and such necessities with adc's.Expensive solution would be to get an bipolar ADC with such high voltage inputs. They exist.Also, nowadays you can get pretty good adc's for a single power rail (eg. mcp600x). I would avoid dual rail unless it is absolutely necessary, and even then I'd create a virtual ground at Vcc/2 using an opamp.

author: fcb
author_rank: Super Contributor
timestamp: July 28, 2015, 09:41:25 pm
content: Rework the resistors around your opamp to lower the maximum gain and re-centre your output to 0 to 3v3 or 0 to 5v.

author: kizzap
author_rank: Unknown
timestamp: July 28, 2015, 11:44:19 pm
content: alternately you could use a differential amplifier and bias the output voltage to half full-scale.and another thing: if you are expecting an OP-AMP to go rail-to-rail, you /will/ have a bad day. AFAIK there are /no/ op-amps which will go to the rail voltage. they will get close, but not exactly there. Put some overhead in your system if you can.

author: Jeroen3
author_rank: Super Contributor
timestamp: July 29, 2015, 05:29:54 am
content: Yes, you'll have severe non-linearity in the lower and upper 50mV. Same applies to your ADC, so there is no big deal.
Extracting power from RS485 / DMX? - Page 1
Forum section: electronics / projects

author: inevitableavoidance
author_rank: Contributor
timestamp: February 27, 2017, 02:53:04 pm
content: I'm working on a simple DMX to NRF24L01 gateway/translater for some lights I have at home, and was wondering whether it was possible to extract power from the data lines. I'm having trouble finding information about this online. Does anyone have any info/experience on this?Thank you a lot in advance,David

author: dmills
author_rank: Super Contributor
timestamp: February 27, 2017, 06:07:50 pm
content: You really, really shouldn't, but there are a few things you can do if you are sure your device is the only load on the line (These do NOT scale, and may severely mis terminate the line).A pair of 50 ohm resistors in series between the data lines will provide 2.5V at a small current from the centre tap, you might get 5-10mA or so this way without messing up the line too badly.Some products used the second data link pair (pins 4 & 5 on the XLR) for power (In one case for 24V power!), or of course if the second link is another DMX universe and you are not using it (Some of the hogs did this IIRC) then you could use that for 5V with a bridge rectifier made of a couple of low voltage diodes.Regards, Dan.
extremely high current out led rgb driver  - Page 1
Forum section: electronics / projects

author: whees
author_rank: Newbie
timestamp: October 12, 2014, 05:07:55 am
content: i need 150 feet of led rgb strips and a driver (or drivers) to power thisi have found some soushin for this but they are rediclie like 5 drivers and i can not link them together. one of the things i would like dmx supporthttp://sell.lulusoso.com/selling-leads/3330287/3CH-CV-DMX-Decoder-TP830-decoder-dmx.html

author: SL4P
author_rank: Super Contributor
timestamp: October 12, 2014, 10:33:59 am
content: Is there a question here, or just promoting the DMX-RGB interface?BTW: The linked product seems pretty good value for the money.

author: whees
author_rank: Newbie
timestamp: October 13, 2014, 04:42:41 am
content: it is a question i posted it because it would be a good example
EZR32HG - Silabs..   - Page 1
Forum section: electronics / projects

author: mrpackethead
author_rank: Super Contributor
timestamp: December 10, 2016, 08:36:24 pm
content: (1) Does anyone else have any experience with this radio Soc?(2) I've struggled for several days to try to find out how you go about using, configuring and debug this thing simply becuase the documentation seems to lacking.

author: wraper
author_rank: Unknown
timestamp: December 10, 2016, 09:02:22 pm
content: I have not used it but just sanity check, had you read reference manual besides the datasheet?

author: wraper
author_rank: Unknown
timestamp: December 10, 2016, 09:27:48 pm
content: For debugging you will need something like J-link or Silabs 32 bit debug adapter. It's Cortex M0+ with SWD interface after all. You can use any silabs dev board with built in J-link (set to debug external device) as debugger as well. IMO Silabs Simplicity studio is pretty straight forward.

author: mrpackethead
author_rank: Super Contributor
timestamp: December 10, 2016, 11:38:38 pm
content: Quote from: wraper on December 10, 2016, 09:02:22 pmyes.,

author: chicken
author_rank: Frequent Contributor
timestamp: December 11, 2016, 03:03:19 am
content: Are you talking about the ARM or radio side of things?I haven't used the EZR32 yet, but from looking into it a few months back, it seems to be a two-die solution where they internally wired up a few pins of the ARM to an EZRadio Pro Si446x transceiver. You should be able to get the radio going by following the EZRadio datasheet, SDK (WDS) and app notes.http://www.silabs.com/products/wireless/EZRadioPRO/Pages/si446x.aspxHere's a receive-only project that I built with one of these radios a while back.https://github.com/astuder/dAISy

author: mrpackethead
author_rank: Super Contributor
timestamp: December 11, 2016, 08:36:06 am
content: its the arm side that is getting me stumpped.. Ironically teh radio side i've been able to configure and modify etc etc.I just cant' find any details on how to program the ARM stuff or how the Gecko SDK works etc etc.

author: ebclr
author_rank: Super Contributor
timestamp: December 11, 2016, 12:30:00 pm
content: Did you installed simplicity studio ?

author: mrpackethead
author_rank: Super Contributor
timestamp: December 11, 2016, 04:52:16 pm
content: Quote from: ebclr on December 11, 2016, 12:30:00 pmYes, i've installed it. It connects and i can push the example code to the dev board.. I was even able to make some minor mods to the code and.. ( change the rate of the LED blink ).. .What i'm struggling with is any documetnation on how you use the SDK, its libtrarys etc.