r/diyelectronics

I want to merge this spliced micro USB cable coming from the Raspberry Pi Pico, to a female USB-C connector. I have a project where I want to make a guitar hero guitar detachable from the outside of the guitar, where I can plug in a USB-C cable when I want to use it. Appreciate any advice, thank you!

Hi everyone,

I have an old 7-inch tablet (HCL ME Sync 1.0) from around 2013 sitting in my drawer. It runs Android 4.1, has 512MB RAM, and a 1GHz single-core processor.

The battery seems completely dead or in a deep sleep. Since I don't want to use it portably, I want to convert it into a small, low-power local home server or kiosk (maybe to host a basic dashboard, a simple script, or just experiment with headless Android).

The problem is: I have never done hardware hacking, soldering, or battery modifications before. I am a complete beginner.

I have two main questions for this community:

1. Hardware/Safety: Leaving this plugged into the wall 24/7 with a dead battery is a fire hazard. Though I somehow removed the battery {idk whether in a safe way or not}, can you tell me how to wire it to run directly off USB/wall power? What tools and cheap components (like a buck converter or diode) would a beginner need to do this?

2. Software: With Android 4.1 and 512MB RAM, what are some lightweight server projects or linux-deploy options that could actually run on this device without crashing it?

Any step-by-step guides, advice on where to solder, or warnings for a first-timer would be highly appreciated! Thanks in advance.

Couldn’t help myself snagging this box of junk for $5 on FB marketplace. Taking it all apart with my 5 year old for fun :)
Bunch of old phones, remotes, robotic vacuums. Got two small gems- an old car phone and a powered 1/4” drive right-angle household power ratchet.
I’ll be saving the motors and sensors for the vacuums. Mics and speakers from the phones. Anything else of potential use in these old phones or remotes that I may be unaware of? I’m a hobby electronics guy and amateur PCB designer (Altium) for simple random shit, mechanical engineer by profession.. so if there’s any chance of use, gimme a heads up. Component level or otherwise.
Cheers!

I dont know any good software that doesnt require paywalls and hides basic features behind subscriptions. I will not use the specified transistors in the schematic, as they are inferior to BC107, BC177 and others. I will replace the Darlington transistor with a BD237 and 2N3055 pair

I tried J-fets, BJTs, MOSFETS, vacuum tubes, any amplifier just for it to go back to fools gold. Everything else failed at a simple task except a frickin rock. It always goes back to fools gold it’s the only thing that doesn’t fail me constantly. Also if you were wondering if this thing was any good it’s not I got like 2 feet with it and I get better range just disconnecting the coil and using it as a spark gap transmitter might add a modulator in order to get an audio signal out of it tho.

Created an irrigation controller for my 12v dc irrigation valve and apparently allowed some solder to short my transistor. Luckily didn’t damage the valve or the pico, but does mean I have to put together another one…

Anyone have tips to possibly avoid this in the future?

There is also this white thing on the lower left...

This is a 6-digit Nixie clock built around IN-12B tubes, with a custom PCB, 3D-printed enclosure, and an ESP32-C3. The idea was to build not just a nice-looking clock using old Soviet-era tubes, but a modern device that can be integrated into a smart home.

What it has:

• Flicker-Free High-Voltage Shift Register Driving — the tubes are driven using HV5222PJ without traditional multiplexing, eliminating the characteristic flicker.
• Smooth brightness control — the display can be very bright during the day or dimmed almost completely at night.
• RGB backlighting for each digit — 2 RGB LEDs are installed under each tube.
• RGB colon — the dots between the digits also have independent RGB control through AW9523B.
• ESPHome + Home Assistant — the clock can be fully integrated with Home Assistant, allowing control of brightness, colors, and effects.
• Battery-backed RTC — the clock keeps track of time even without Wi-Fi or external power.
• NTP synchronization — once connected to Wi-Fi, the time is automatically synchronized.
• USB-C for power and firmware flashing.
• Additional I2C — external sensors such as temperature, humidity, or CO₂ sensors can be connected.
• Custom PCB — all electronics are integrated onto a single board, including the high-voltage converter for powering the Nixie tubes.
• 3D-printed enclosure — the enclosure files are open source as well.

The RGB backlighting can also be used for more than just decoration. For example, you can automatically dim it at night, change the color depending on the time, or use the lighting for notifications from Home Assistant.

The entire project is available on GitHub.

The repository includes the schematics, PCB files, Gerbers, BOM, firmware, and 3D-printable enclosure files. So if you want to build your own, you can order the PCB, get the components, print the enclosure, and reproduce the entire clock.

The main components cost around $150–200, depending on where you source the tubes and other parts.

Hey everyone, I'm currently building a robotic arm project and would really appreciate some feedback from anyone with experience in mechanical design or wiring, specifically on what I might have done wrong so far and any practical ways I can improve its overall build quality, stability, or functionality.