Ask Electronics

I have a controller for an electric throw blanket that I would like to repair, but I have no experience soldering on boards

You can see at bottom left a yellow box and a resistor. Something has burnt out in this area, and likely both will need to be replaced at a minimum

I would also need help identifying parts. The yellow box is embossed 'Tenta' and has printed on the side 'TC MEX/TENTAMKP 0.1 uf 275VAC' with some other markings obscured or damaged

Is this an achievable project?

So there are tons of 12"x9" magnetic grids out there for dropping screws onto when taking apart electronics, but my projects typically involve integration into other materials.

Having a sewing mat (about 24"x18") with all the metric/imperial grid lines and angle lines, but with a magnetic backing for holding screws in place would be perfect.

Has anyone ever tried to make a DIY magnetic desk pad? And if so, how did it go?

Hi, hope this post is fine in regard of rule 2.

Currently doing some fun stuff with an Arduino and have it hooked up to an 128x160px and communicate with it over SPI. If i color in all 20480 pixels it takes about 2 seconds to be done and i can watch the rows change one after another.

I was wondering if there are some tricks to speed this process up a bit or does it really just come down to minimizing the pixels to be changed?

The module im using is this one: https://www.waveshare.com/wiki/1.8inch_LCD_Module

Here is also my current code if anybody cares to take a look, even though i just rewrote the example code more or less so i would understand it. https://codeberg.org/bvoigtlaender/open-phone/src/branch/main

EDIT: Thanks to jeinzi, nickwitha_k and cmnybo I have managed to bring the rendering time down from 2142ms to 80ms

• write directly to registers keep in mind that the pin is different when using that method 2142ms > 1912ms
• write bigger chunks of data 1912ms > 272ms was indeed too good to be true... it just didn't render anything at all have to look a bit more into that
• set spi clock 272ms > 80ms

After playing around with some greeting card modules to modulate sound onto a LED i found out that the driver part of said greeting card modules are not audio drivers but PWM drivers (oscilloscope confirmed).

This made me wonder if normal PWM controllers could be used to drive more power full LEDs.

My idea was to just remove the potentiometer and feed in music from Aux at that point.

Is there a chance of this working?

Update: I just tryed if it works and sadly it dosent, LED gets modulated somewhat but there is not audio to recover from it afterward, its only noise.

I tried to start my laptop earlier, only for nothing to happen. It won't start on battery or when plugged in (it can run without a battery when plugged in). The battery does seem to be dead, and so is the 3V CMOS battery.

I opened it up and noticed a circle visable on one of the inductors. Hopefully you can see it in the picture.

Could this be the problem, or is that normal?

Update: I've tested some suggestion and watched some repair videos, but I found nothing. Goodbye old friend 🥲🤚

Thanks for the help guys

I’m trying to fix my daughter’s electric scooter. The company sent me a brand new motor, out of warranty, however the adapter is wrong (see pic). I’m thinking I’m better off swapping the couplings rather than cutting and splicing, but I don’t want to destroy them - what is the best way to remove the wires? There appears to be some sort of yellow wax/paste holding the wires in.

EDIT: Thanks to all who replied; I’m going to try and splice the wires. Solder should be here tomorrow, so hopefully she’ll be up and running in no time!

So i have this sound module "FLR104A-A-V1.4" and it works fine, i can record and play audio with it.

But i am struggling to get the loop function working.

Sadly the Chip dosent have markings on it so i didnt found a datasheet to help.

There is a pad called "Loop" but it dosent seam to do anything, i tryed connecting it to VCC ~~or ground and~~ it dosent make the module loop.

I cant use a NE555 timer to trigger looping via play button because the sounds on it wont be the same runtime every time.

Any ideas?

Update: It may be a ISD1820 style Chip but with 4 min of storage compared to the usual 10-20sec...i cant find anything about it online

Update 2: from the functionality it could be a ISD4003 but it has to few pins for that

Update 3:

After soldering those 2 pins together AND hitting the playbutton it loops. It dosent loop on its own when turned on sadly there is still a initial play button press needed but i think this should be fine for now-

Update 4: Sadly the recording only loops 4 times and then stops again :/

Update 5: Connecting the loop pad to the negative side of the play button seams to send it into a endless loop yay

It looks like all the current options are just for AC

I messaged the seller asking for the exact name of the connector, but they just reiterated the listing title. I need a two Metri Pack-150 connectors, but I can't find prewired ones and I'd rather not buy a 200USD kit.

Trying to reuse this screen for a project I'm working on (yes I know I can buy another display for cheap, but I hate to waste a perfectly good display that I already have) but I am having difficulty tracking down a datasheet or even just a pin out

The text is "2.4HYDIS171+9325 24PIN", but I've tried searching it 6 ways to Sunday and nothing useful comes up.

I do know that the matching pin out should have the LED anode pin on pin 1, LED K/GND on pin 2 and VCC 3.3v on pin 3. It's also a 2.4" screen and should be a resolution of 240x320

I've probably gone through a million Alibaba listings, and while some get close they just miss the mark

If anyone could help me out that'd be amazing!

Additional pics:

I have a simple circuit where 5V signal is fed into a buffer (Nexperia 74LVC1G07), then from the buffer into another device. The buffer is fed 5V by a switching DC-DC (R-78HB5.0-0.5/W). After it's been off for a while, the buffer works, the signal is recognized by the receiver. This continues for some time, minutes, to tens of minutes. Then the buffer stops working. The DC-DC still works as well as the source. If I unplug it and let it sit for an hour, it resets back to working for a while until it stops.

Context:

The setup runs on an ebike 36V battery. Theres a hub motor connected to the same battery (via power controller). The signal source is a torque sensor. The destination is a bike computer.

Any idea what could be causing this? I don't know much about electronics. I learn specific bits to do something but I'm ignorant otherwise. E.g. I know what a buffer does, I understand how it works on high level but I have no clue for example how it could be affected by the rest of the system electrically through noise, EMI, etc. My physics intuition here makes me think there must be some charge buildup happening which dissipates with time when turned off. I've no idea if this is remotely valid, or if it is how to fix it. Any ideas are appreciated!

I just found out I can buy a decent 400W solar panel in the local hardware store for around 90€ these days.

Are there people around with experience in off-grid solar? There is quite some supply in cheap MPTT charge controllers on the internet. And I can't afford a 700€ power station. But I would be able to buy a few power tool batteries or one of the lead-acid batteries people put in their caravan. Are there projects building a power station myself? Is this even worth it?

Maybe someone alredy wrote a blog post with recommendations or findings and failures along the way. Or has something similar running at home?

(Thanks to the mods for steering me towards the correct community.)

Hi all. Does anyone have experience with the BMSs from Daly? I'm looking to get a 16s BMS for a DIY li ion battery pack. I have a large box full of li ion 18650 cells and want to make an emergency battery system for home use.

That power outage in Spain motivated me to finish this project.

I'm using an Arduino and through a library working with an IC (MCP2515, a CAN controller) over SPI. The IC indicates interrupts by causing a falling edge on an interrupt pin.

Components are connected using jumper wires on a breadboard.

• When a logic analyzer is not attached, the IRQ gets called a few hundred times. It should only be called once. I thought it must be noise on the external interrupt pin but a pull-up doesn't help. I've tried the internal pullup and an external one.
• Trying to see if there is a ton of interrupts from the IC, or an error internal to the Arduino, I attach my logic analyzer. Now it works perfect.

Any idea what might cause such a weird issue? Looking around I haven't found anything.

EDIT: I found a Reddit post for a different circuit where a user suggested placing a small capacitor to make the edges of a signal rise slower. This has fixed my problem.

Since I've already created a post: does anyone know why I was getting an unending number of interrupts? Why would the edges of the interrupt signal changing too fast cause something like this?

It's the trace going towards the mode button, so I'm pretty sure resistance won't exactly be critical over a ~3mm gap, as long as it recognizes when the plunger button is pressed down.

Not sure if this is a dumb question but this has me quite puzzled.

The legs on TO220 packages are very small. How is it that there are e.g MOSFETS rated as being able to continuously conduct ~100A? e.g IRF1404Z

From what I understand such large currents need busbars on PCBs and these appear a lot larger than the legs on these components.

I have an inspection scope camera that I'm attempting to repair. It's one with a camera on the end of a flexible rod to see into tight spaces. The pins that lead to the camera came out of the connector. I tried looking for teardowns or even replacement parts, but found nothing.

Two pins are still inserted, but I'm not confident they are in the right places. I want to get it working without the risk of frying everything. I've done my best to find where each pin goes, but there's not enough info for me figure it out on my own. The camera rod also includes an LED for light.

Here's a photo of the connector as it is:

And here is the socket with it's pins labeled (the labels correspond to the testing pads and not to the socket pins):

Here's a zoomed out pic if it's of any use:

I have a multimeter, so I can do any testing you can suggest. Unfortunately, I was not able to disassemble the camera to trace any wires.

cross-posted from: https://lemmy.ml/post/28250870

Hello everyone !

I'm seeding/cross-post this in 3 communities because I think I will get better answers in each respective one (Hardware, coding, electronics).

As the title say I'm want to learn to build from the ground up those cheap solar led/optic fiber lightning, here some images to get what I mean:

They come in bundles but after awhile they just die out without repair ability which kinda sucks and because they are cheap my mum keeps buying them... So, I would like to build ones I'm able to repair and customize :). However I have absolutely NO idea where to begin and what exactly I'm searching for... I'm lacking the skills and knowledge on the 3 fronts !

• What hardware I'm looking for ?
• What kind of electronics ?
• What programming language to glue everything together?
• .... ?

I'm not afraid to get my hands dirty and learn how to micro-solder, learn some coding skills to get everything neatly glued together software wise, learn the necessary hardware or other important and necessary stuff to achieve this goal ! I'm looking for every good and reliable advice to get me started !

One thing though, If i have to learn some hardware/low level coding skills I would prefer a language that would be useful for other stuff in the long run.

Thank you in advance and I'm already sorry if I'm very slow to respond, I'm not native and the flood amount of information I will probably get, will surpass my ability to respond to everyone right away.

Also every other directions are welcome, like:

• how to repair the old ones? Do I need to flash their proprietary software/hardware?

Thank you !

I replaced this battery last fall, but it has drained over the winter. The auto-mower dock wont charge it. Is there any feasible way to charge it safely? Or is it dead at that voltage? It’s a Bosch Indego 400. Thanks in advance.

Hi, Any1 have experience with this usb to TTL 6 pin converters? I just want to know if I have a dodgy one that I bought from Ali or normal behaviour.

Doesnt seem right. I have it plugged to a powerbank, following voltages read from pinout, without any jumper link.

5v = 5.3 Vcc = 3.9v 3.3 = 3.2v Tx RX = 3.9v

If I use jumper link from 5v to VCC, then tx RX = 5.3v, if I jumper link VCC and 3.3, RX and tx = 3.9v.

Thanks for reading

Photo of product http://0x0.st/81fc.jpg

I'm making a driver for a small 15V, hall sensored, 9-slot BLDC motor I got off of AliExpress. It has u,v,w inputs. Three hall outputs and Vcc, Gnd for them. No datasheet :)

I understand the working principle: I'll have to use the hall sensors to figure out the location of the rotor, then power the appropriate windings.

Trouble is, I don't know how the windings for the three phases are arranged within the motor. So I don't know which pin to give power to, because I don't know which windings within the motor will then be powered.

How can I figure out where the windings are for each phase?

I'm guessing I've got to manually spin the motor and do some detective work with back-emf measurements and hall sensor outputs to figure this out?

I've an UPS but it's not working fine. Disassembled it a bit and tested components that I could without unsoldering, everything seems good. Then the problem is :

• Normally I should be able to connect the batteries and the UPS would just be in "sleep" mode, the screen would be fully light up but the UPS should be off

• The problem here is that firstly when I plug batteries the fan turns on, it should not and only turned on when on batteries but when the UPS is on

• The second problem is that the screen doesn't work as intended. This is a screen that has prewritten zone that just have to be lighted up (don't know the name of this kind of screens, the type like in digital clock), here only the backlight is lighted up (normally all the possible drawing are lighted up too), but quickly it begins to drop in lightness to turn black at the end (the fan continues running)

Check the batteries they are 2 x 12V at 12.6V here

Thanks for your answer

EDIT : on the photo the two blue and brown cable at right are the power plant electricity going to the UPS

So I'm not sure what the right community for this is but I'm hoping yall can help. I'm a refrigeration service tech and recently I was tasked with replacing a sensor in a room used to store ethanol drums. Due to the nature of the room every device in it had to be rated explosion proof and I couldn't use any tools that could pose any risk of ignition (no heat gun, basically nothing with an electric motor, and definitely no open flames) while working in there. Normally when I splice wires I use heatshrink to cover the splice simply because it looks far more professional than electrical tape and it holds up better over time. However in this case I could not figure out any way of shrinking said heatshrink without posing a potential ignition hazard so I was stuck just wrapping the splice in tape. We do a lot of work for this company so I'm hoping to find a better solution for the next time I am in a similar situation.

So do any of you know any way to shrink heatshrink without posing an ignition hazard or am I stuck just using tape in those situations?

Hi all! I'm a firmware developer with little knowledge in analog electronics.. I deal with firmware for IOT projects all the time.

I had to make a breakout board with an off the shelf RF module with self contained PCB antenna. Now I'm intrigued in the hardware side. I'm inclined to design them from scratch myself. (Obviously ignoring the EMI and FCC certifications for the time being).

What concepts should I be familiar with to achieve this? Starting on I figured to brush up on circuit theory and signals. Where do I go from here? What materials would you recommend? Hopefully I don't need to get into hardcore RF theory to design these PCBs (I know kicad already has these premade antenna blocks).

Thank you.

I'd like to build a small light that i can use to cast a shadow to a wall.

It needs a single led that's really small and bright and that can be recharged. Also I want to put it in a special casing.

However I don't really know how to build one myself. So I had the I bright idea to take apart a flashlight that is rechargeable, but I'm not sure which one can be dismantled.

Do you have any idea what flashlight I could use or what parts I would need?