Reddit:Electronics

Recently my £350 Bluetooth dongle had it stupid micro usb connector snap off.

I have a 3D printer so I’m going to print a new case to contain one or two 18650 or 21700 batteries. I’ve found a PCB on Amazon that takes a USB-C connection and charges 18650/21700. I know the basics of electronics but wanted to double check before I blow up this £350 dongle

Since the battery on it is a 3.7v and 18650/21700 are 3.7v too, can I just go from my 18650 bms to the connector where the old battery is directly? Or will I fry something?

I’m worried that it could get fried when charging, I can’t find any specs for the battery it currently has. I won’t be charging the new battery through the dongle as the USB connector has broken off. Instead of trying to fix the traces and add a new one, I want to 1. Replace the battery with something bigger, and 2. Have a way to charge this

Thanks for any help :)

This is a capacitive touch sensing number pad for a lock. I've not yet tested it, but the touch sensor is self calibrating, so it should work. I have tested that the sensor works with a loop of wire through the plastic sheet.

I used a knife to cut out the traces and pads, but I used a printed template exported from Kicad, so I think I can still call it a "printed" circuit board.

I'm aware that trace 5 is broken and has to be repaired. I've also been made aware that lock numpads and computer numpads have the keys in different orders, and I used the wrong one.

Took a broken CD V-700 apart and replaced the insides with a microcontroller and a new detector.

Forgot to order 0R2 resistors in my BOM. Oh well, time for some good old fashioned botching to save the day.

Hi! I just bought a new old stock KBMM 225 driver, 18V obviously it came with the wrong plug in resistor and fuses so I need to source new ones, my motor is 520w at 180v and it seems I need a 0.35ohm one, I'm not sure about other paremeters though, can anyone help finding a suitable one from RS or Conrad or digikey? Thanks!

Spotted this monstrosity in the wild

It has no any practical purpose. However I think it got somewhat fancy so I post it.

So it has adjustable output voltage and overcurrent protection. The goal was to make something with minimal set of basic parts.

Simulation here https://tinyurl.com/ywqfok6x

Would be cool to hear any design suggestions, but again it is just for fun and probably won't be wired