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So I'm doing some testing of USB-C cables using a tester and a constant load (I'll have another post soon with some questions on this). But before running each test, I'm checking the E-mark chip and then enumerating the charge capabilities of each to see what they report being capable of.

I'll use 3 different brands of cables as samples of my question. Power Supply (PS) 1 is an Anker 100W with PPS support. PS2 is a MacBook Pro 94W brick with no PPS support.

• Cable A
  • Emark: 20V@5A USB3.2 Gen 2
  • Max PD using PS1: PD3.0 PPS 29W
  • Max PD using PS2: PD2.0 94W
• Cable B
  • Emark: 20V@5A USB3.2 Gen 2
  • Max PD using PS1: PD3.0 PPS 100W
  • Max PD using PS2: Not tested
• Cable C
  • Emark: 50V@5A USB2.0
  • Max PD using PS1: PD3.0 PPS 29W
  • Max PD using PS2: PD2.0 94W

So the question: What would be limiting Cables A and C to PPS 29W?

Hello,

Either my web search terms are quite inadequate, or perhaps no one ever wants a conveniently pre-wired holder for batteries connected in parallel.

Tried at standard (USA) sites like DigiK-- and Mous--. The in-series 2xAA=3V, etc., are even available at general merchandise retailers as shown in this pic from an A---zon listing.

Would appreciate comment.

I want to power this board with a 14v battery. The board has a 1s battery connector that can power the board and read the voltage via ADC. Is there something I could place between the two to lower the voltage and still have a battery voltage reading? I would not be charging the battery through this. The usb port would not be open in the final product.

My understanding is that voltage splitting with resistors is not recommended for powering. And a buck converter will only give constant voltage reading.

Hi, my cousin has an Xbox Series S, and anytime he would move it the fan would make some pretty freaky noises.

I repair computers so I thought I can handle this. I also replaced the thermal paste, and ultimately found the fan to be really loose.

I ordered the replacement fan but when I tried to power it on to make sure I did everything correctly it didn’t work. It made the startup noise, fan would spin and then shut off. No error messages.

I removed a coat of thermal paste and was very careful when working around the CPU. I am scared I broke his Xbox now that there is no error codes or any message, and abruptly shutting off after a few seconds of the fan spinning.

I won’t know until tomorrow when the fan arrives and I power it up.

What should I do?

I am curious if one, something like this exists, and two what the cost might be? I am looking for a screen, I assume an e-ink is the best/cheapest option and I want it to be as close as possible to the size of a playing card, ideally not thicker than 2MM. But I think up to 5mm could work.

Basically the idea is to use and or eventually create very thin cheap e-reader screens to make programmable playing card games. I have no idea if the screens are even that small, when I go to look for them I get results that are very far from what I am looking for.

Anyone know if what I want exists, and if not, if it would even be possible to manufacture for cheap?

Edit: I wonder how hard it would be to repurpose something like this?

The idea is that all the "cards" would be inserted into a carring case that acts as a dock to update the cards. Once you pick your game, all of the cards refresh to whatever game you picked. I would want to make the games open so anyone can design a game for people to play.

Disclaimer: this is not specifically for a commercial product, but various things I design sometimes get commercialized. I mention this so that you may decide whether you want to weigh in. If it's commercialized, I will probably make very little money but a bunch of university students may get a neat STEM program in the countryside :D

That out of the way, I've designed some boards for a Wi-Fi controlled robot with mechanum wheels. So 4 independent motor drivers, one for each wheel, allow omnidirectional motion. It's built around a Pi Pico W, 4 SOIC-8 9110S motor drivers, and some buck/boost converters to give the system a 5V and 12V line. It's very basic, mostly made to be cheap. Here's a photo:

Right now it just receives UDP communications (a little app written in Godot) and activates the motors in different combinations -- very "hello world". I'm planning to add some autonomy to move around pre-generated maps, solve mazes, and so on.

I have foolishly used 2-pin JST connectors for the motors, so using motors with rotary encoders would be a pain without ordering new boards. I'll probably fix that in a later board revision or just hack it in. Also the routing is sloppy and there's no ground plane. It works well enough for development and testing though :D

What I'm thinking about right now, is how to let the robot position itself in a room effectively and cheaply. I was thinking of adding either a full LiDAR or building a limited LiDAR out of a servo motor and two cheap laser ToF sensors -- e.g. one pointed forward, the other back, and I can sweep it 90 degrees. Since the LiDAR does not need to be fast or continuously sweep, I am leaning toward the latter approach.

Then the processing is handled remotely -- a server requests that the robot do a LiDAR sweep, the robot sends a minimal point cloud back to the server, which estimates the robot's current location and sends back some instructions to move in a direction for some distance -- probably this is where the lack of rotary encoders is going to hurt, but for now I'm planning on just pointing the forward laser ToF sensor towards a target and give the instruction "turn or move forward at static speed X until the sensor reads Y", which should be pretty easy for the MCU To handle.

I'm planning to control multiple robots from the same server. The robots don't need to be super fast.

What I'm currently wondering is whether my approach really needs rotary encoders in practice -- I've heard that mechanum wheels have high enough mechanical slippage that they end up inaccurate, and designers often add another set of unpowered wheels for position tracking anyway. I don't want to add more wheels in this way though.

On the other hand, it would probably be easier to tell the MCU to "move forward X rotary encoder pulses at a velocity defined by Y pulses per second, and then check position and correct at a lower speed" than to use a pure LiDAR approach (e.g. even if rotary encoders don't give me accurate position, on small time scales, they give me good feedback to control speed). I could possibly even send a fairly complex series of instructions in one go, making the communications efficient enough to eliminate a local server and control a ton of robots from a cloud VPS or whatever.

Anyone have some experience with encoders + mechanum wheels that can offer a few tips my way? At this stage the project doesn't have clear engineering goals and this is mostly an academic exercise. I've read that using a rigid chassis and minimizing the need for lateral motion can reduce slippage, reading through a few papers didn't get me any numerical indication of what to expect.

Some years ago, before LEDs were a thing, I bought an Ultrafire WF-500 Flashlight that features a Xeon light bulb. As you might imagine the bulb reached its lifetime and burned away.

Now a replacement bulb is available here https://www.ebay.com/itm/321916301663 the thing is that it will cost me 35€ and for that price I could just buy a new LED flashlight.

Now I was considering trying to adapt a generic LED bulb like this one here https://www.aliexpress.com/item/1005002419159094.html?mp=1.

Anyone else with this model of flashlight succeed at a similar mod? Any LED bulb recommendations? Or... is there any other source for the original bulb at a lower cost?

Some photos:

• https://cdn.tcb13.com/2023/wf500-bulb.jpg
• https://cdn.tcb13.com/2023/wf500-bulb2.jpg
• https://cdn.tcb13.com/2023/wf500-bulb3.jpg

Thank you.

Hi all, I have a water pump connected to an adapter (pictured) but I am having trouble getting it to run using any of the cords I had on hand; it calls for using DC-only & 12V (between 9-14). I have tried Googling around & browsing Amazon but I'm a bit overwhelmed with options. Can anyone suggest an adapter that'll get this little guy pumping? Please forgive my naivety & TIA.

Also, I hope that it's kosher I ask here. If it's not, please let me know if there's a better place. Thanks again.

I am powering a 5V microcontroller (arduino clone, atmega328p) using a 9V block and a buck converter. Now I want to let the microcontroller occasionally measure the battery voltage, so I can get an idea of how full it is.

My first idea was to use a simple voltage divider:

I've chosen the resistor values so that:

• the voltage at the measure output is < 1.1V, to be able to use the 1.1V internal reference of the atmega's ADC
• R1 || R2 < 10kΩ, since the atmega datasheet says "The ADC is optimized for analog signals with an output impedance of approximately 10 kΩ or less"

This is great and all, but what bothers me is that this circuit will constantly draw ~100µA from the battery.

So, my next thought was to add a mosfet to the divider, to switch it on only while measuring:

This is obviously bad, because now when the mosfet is off, the ADC input sees the whole battery voltage.

To address that issue, I've added a second mosfet into the measure path:

This works, and it does not draw any current, except while measuring.

However, it's quite a few parts. So I'm curious if anyone has an idea how to do this with just a single mosfet. It seems to me like it should be possible, but I haven't figured out how.

Oh, and if I'm doing something stupid here, please tell me :)

Is there a way to figure out my LED board and fix it myself? I got this LED light which works perfectly but the issue is the usb charger port on the left is not working for whatever reason. There are two ports one micro for charging the led and one usb for outlet charging. Is there a way to switch the charging to the usb port? If you guys have any resources for learning I would appreciate it too, I will get my feet wet and hopefully figure it out myself…

I am making a graphics card on the tang nano 20k board. I tried synthesising the design in the official IDE and it output:

[95%] Generate netlist file "/home/original2/Downloads/Gowin_V1.9.8.09_Education_linux/IDE/bin/VGA_out/impl/gwsynthesis/VGA_out.vg" completed

with no further updates for 40 minutes so far. I am on a 16 core system with 24GB of ram (the process is maxing out 1 core right now as well as using 6GB RAM). Why is it not progressing..

I do have a 60 by 80 array with 11 bit numbers in it if that is relevant

Hello! What would be a good way to learn about electronics in terms of creating them? I'm particularly interested in building my own keyboards and other PC peripherals, but I'm not sure what tools I would need, or what's a good knowledge base if I run into any issues. Any tips and or suggestions?

Thanks for all your votes and comments. From the icons that were submitted as requested, the results were as follows:

• Icon 1: 7
• Icon 2: 78
• Icon 3: 27
• Icon 4: 6

Icon 2, by @Double_A has duly been adopted.

In a transformer, why are both coils apart from each other? Wouldn't make more sense to have the ferrite core (tube shape), wind the primary coil around that and then wind the secondary coil on top of the primary? So that the magnetic fields are as close to each other as possible?

My wife gifted me this super cute mini miffy diorama from a gachapon. It uses two 1,5V cells and has a tiny led in it. I would really love to to add a 24h timer. ( it should stay on for 4 hours after turning it on then go to "standby" for 20h before turning back on) Do you guys think an attiny85 is the right thing for the job? Sorry of the question is dumb in any way. I am absolutely not an electronics guy.

Hi,

I'm looking for some help in a field that is super technical and I don't fully understand.

I'm planning on using a bunch of these seeed studio Esp modules for some home automation projects, especially because they have a lipo battery charger making it great for portable stuff.

The thing is the the ESP32s have U.FL SMD antenna connectors. Most of the antennas that you can buy with U.FL connections while are reasonably small, come with 50-150mm leads, which sort of makes the small size of the module a little less valid.

What I'd like to do is get a female U.FL SMD connector and make a small daugherboard with an 2.4GHz SMD antenna on it, for instance a Janson 2450AT42B100 or a Molex 479480001.

They go over the circuit board requirements quite thoroughly so I don't think designing it will be too difficult, but what I don't know is, they say that you need impedance matching on the circuit, and I see that there appears to be something that looks like it on the ESP circuit diagram, but I'm not actually sure if it is or not:

You can see it in the middle near the bottom of the diagram here: Seeeduino-XIAO-ESP32C3-SCH

So my questions are:

1: Is this a dumb idea, having a direct plug-on SMD antenna?

2: Is that an impedance matchning circuit between LNA_IN on the ESP chip and U.FL-R-SMT-1?

3: If I can't get a female U.FL SMD connector, would using one with a lead and shortening it to make the daughterboard able to be much closer to the connector affect anything? Do I need to ensure that the lead length matches the wavelength at all?

Edit: Found this SMD female U.FL, so they do exist.

I got my hands on an old e-ink price tag and want to repurpose this display.

Unfortunately, I can't really figure out, what this type of connector/bus is called. To me it looks like a standard issue ribbon cable.

There are some "universal" e-paper drivers (for example this one: https://www.ebay.de/itm/353141399922), but I have absolutely no idea, how to find out, if that's the right connector.

The device is made by Imagotag, if that helps.

Edit: I added a picture of the panel: https://feddit.de/pictrs/image/42ee4f60-231a-4c42-9a66-6c369134c49c.jpeg

None of the "markings" returned any results and the QR code couldn't be decoded by my phone.

Hi, I am automating my manual switches at home with ESPHome on NodeMCU. For controlling the switches, I am using 8 channel relay module.

The back of the board has solder-points sticking out. I will be installing this relay module inside the switchboard. So I want to put it in some kind of enclosure.

Just wanted to know your thoughts on enclosure. Should I just wrap the whole thing in electrical tape? Or a plastic box maybe?

Hi everyone! Recently I have gotten interested in communication protocols and have been looking for one (with little success, hence my question) which would satisfy the following requirements (in prioritized order):

• All devices should be able to initiate communication (not your typical master slave with polling)

• Devices should be able to address messages directly to one another without a single one permanently taking on some host/master/relay role

• Devices should be hot-pluggable (A new device may be connected to the network or removed from it without problems even when the network is up and running)

• The protocol should be stable and immune enough to noise so that it can be sent through wires up to at least 5 meters, ideally even up to 10-50 meters.

• It should be simple, implementable even on low-perfomance microcontrollers.

• It should have its maximum transfer rate in the kilobytes per second range or preferably even megabytes per second.

I have looked at I2C, which for the most part would be fine, but as far as I understand it was not meant to be sent through a wire and it would be quite vulnerable to interference. (It also is by default a master-slave protocol, but it also has a multi-master mode, so maybe making every device a slave and a multi-master master at the same time could work?)

The rest of the protocols I looked at were all master-slave, which, for my purpose, is unacceptable.

That being said, I would be grateful if you could give me some pointers as to what protocol may satisfy these requirements and perhaps even on what sort of wires and signals it would require (twisted pairs? Differential signal? Shielded twisted pairs? Could plain simple wire suffice? etc.)

I just came across this and thought I'd share. I've struggled to get headers and IC's off boards after soldering them on backwards/upside down. This video shows a cool trick with a piece of copper wire that makes them very easy and quick to get off without expensive tooling. I was thoroughly impressed. Hope someone else finds this useful too.

I purchased an e-bike which was advertised as just needing the batteries replaced. The li-ion batteries had been sitting dead for months. Once I got the battery removed it was clear that was not the case. You can see the hole where the plastic melted from this component overheating on the board. The burnt one is the same as those in the center of this photo.

What is it and how do I determine the correct replacement?

I replaced my laptop's battery after it was swollen. I found out that services like call2recycle do not take swollen batteries since they are potentially hazardous material. How can I get rid of that damned spicy pillow? In Dallas. Thanks.

Thanks for the suggestion and tips guys. I have bought lipo fire resistant bags for the batteries. As stated in suggestions here, most of the places like Home Depot, Best Buy, Lowes do have a recycling program; but some of them have disclaimers regarding not accepting swollen batteries. I plan to go to Batteries and Bulbs, Best Buy asap; they look most promising.

Trying to identify a component on a pool control board.

It's related to the T-Cell functionality of the board, since everything else like sensing, timing, and whatever else works on the board.

Component got water on it, most likely when a not uncommon occurrence of water jetting out from the filter and splashing onto the board eventually got where it shouldn't.

@askelectronics