Reddit:Electronics

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I couldn’t find a bench lamp that was inexpensive and met all my requirements. I wanted the light to be fairly diffuse, have adjustable brightness, and be positionable in any way I wanted. I particularly wanted to avoid shadows and reflected glare.

In the end, I decided to make my own. For the angle-poise stand, I bought an AliExpress phone mount, meant for filming things on desks. It was about a tenner and has all the adjustment I could wish for. Then I bought a 12V COB panel, also from AliExpress, for about £1.50. I always intended to underrun it, but even so, it gets fairly warm — so I stuck two 25x100mm heatsinks to the back using thermal glue.

Finally, to power it, I used a boost converter set to output around 10.5 volts (I know that’s not exactly “adjustable,” but I’ll live with it for now), and soldered a USB-A plug to the input.

In the end, I’m delighted with it. Not only is it perfect for my soldering and other assorted nerd tasks, it was also incredibly cheap — the whole thing cost less than £15 — and I enjoyed every moment of making it.

Hey all! This is my first project and my first post here. I know it's a simple project, but I'm still really proud of how it turned out and wanted to share.

My friend and I are making a Bluetooth speaker for calls. Unfortunately, we assumed that audio was audio, so any audio amp would work for calls, but turns out different amps are needed for calls so all I could play on this one was music.

First, I put it all together with the breadboard and tape, and it was working but the signal was sparce, owing to loose connections with tape. So, I decided to solder the connections for a more continuous signal.

These are standard jumper wires from an Arduino starter kit; I presume you're not really supposed to solder them. But this was a throwaway prototype, I had plenty of wires, and I wanted to get experience soldering quickly, so I just did it and tried to desolder them afterward.

All in all, considering this was my first time soldering and I only burned myself once, I'm prepared to call this a success.

I know this setup doesn't look very safe; it was all done very impromptu. My friend probably has a better setup, but he wasn't available, so next time I'd like to do this at his place. If I keep doing this on my own, I'll go outside until I get a better setup.

Video Link: https://imgur.com/a/OUeYEi9

Song: Can You Hear the Whistle Blow by Default (缺省)
https://open.spotify.com/track/2bJjScKqL6XqhwL30X2SaZ?si=a9feec2f349c4391

缺省 Default - Can You Hear The Whistle Blow (Official MV)

Components:

XJ8002 Power Amplifier: 10PCS/LOT HXJ8002 Power Amplifier Board Mini Audio Voice Amplifier Module Replace PAM8403 - AliExpress 502
Bluetooth Audio Receiver Board VHM-314 (Type-C model): Bluetooth Audio Receiver Board VHM-314 Bluetooth 5.0 MP3 Lossless Decoder Board Wireless Stereo Music Module 3.7-5V - AliExpress 44
Speaker: 5pcs/lot New Ultra-thin Mini Speaker 4 Ohms 2 Watt 2w 4r Speaker Diameter 40mm 4cm Thickness 5mm - Acoustic Components - AliExpress

Breadboard, jumper wires, & 1k ohm resistors from REXQualis Starter Kit for R3 Project: Amazon.com: REXQualis Super Starter Kit Based on Arduino UNO R3 with Tutorial and Controller Board Compatible with Arduino IDE : Electronics

im not sure if this is allowed to be posted here, just scrolling and deleting pics from my phone and i found old pics of my uni class works and projects that somehow went wrong so often while i did nothing wrong. im pretty confident with my wiring and building the circuit because i used to be doing all good with correct results, but in my third year things just gone weird on my hands. i have officialy broken THREE breadboards and TWO arduino uno boards. context behind the second pic; i was building the circuit on the textbook but halfway through when i inserted a new jumper wire to ground row it sparks. no electric source, all machines were off. i told the lab assistant about my problem and he didnt believe it until he did what i did. in the end he just told me to buy a new breadboard.

whenever i retold this story to my seniors or friends from the same major, they kept on telling me "stop making up weird stories, i had my breadboard since high school", "did you break the arduino board in half? that thing is impossible to break", yada yada yada.

the project with arduino one was very important to me since it's a mandatory final project. even the simplest command would went wrong while there was nothing wrong physically, like the wrong LED lit up while it's not connected to the wiring i was testing, got 100% sensor reading while i didnt expose the sensor to anything yet, and the most frustrating was how often it sent me failed uploading message even if i have reset it, change the wires, clean the ports, multiple times. D-1 presentation morning everything finally worked but it had to be run separately (i used 3 sensors) so i quickly documented everything for the ppt attachments, but holy shit that evening it wouldnt let me run it again. so i ended showing up only with my poster and ppt (the paper was submitted via web). honestly im still very thankful that presentation was not graded, just need to show up and present it to the guests. it's just a mandatory project for the semester with progress reports every week and my professor said to not think about it too much, since he saw every weird shit from my project (he is also a very nice person as well). i could still remember showing up for the biweekly progress presentation just to show the video of me trying to show the sensor reading but it came out all different in multiple attempts and got stared by my project mate (1 professor could take 5 groups of students, i just volunteered to do the project alone since im an international student and i tried to avoid any miscommunications). that was the last time i touch any hardwares, not graduated yet since i failed a lot of classes which makes me wonder if this 4 years of uni actually worth the struggle.

thanking everyone that read this until the end.

Hi,

Built Ani Music 🎵 – a pocket PCB piano powered by RC oscillators and NPN transistors.
8 keys, each with a different resistor value → different notes, played on dual buzzers.
Runs on a 3.7 V battery, fully portable, and turns electronics into music.

I posted V1.0 here a few months ago and a couple people pointed out some problems. I also found some of my own. I need to change the design, so I've made V1.1. I've made a lot of improvements to the board and my documentation. All of my progress can be tracked in the v1.1 branch on my github. I am planning on ordering new boards soon. Any feedback would be appreciated.

Project 1: µController - A Custom Game Controller for Unrailed

I designed this compact controller specifically for playing Unrailed. Here's what makes it special:

• Custom PCB with USB-C connectivity
• Battery-powered with a boost converter for stable 5V
• Hall effect sensors for precise control

The journey wasn't without its challenges - I may have slightly overheated a Nano S3 during assembly 😅 but managed to salvage it with some creative bodge-wiring using a Xiao. Currently, it's fully functional except for one hall effect sensor!

Project 2: The Overkill Macro Pad

Ever thought "I need more buttons"? Well, how about 100 of them?

Features: - 100 mechanical switches - Individual RGB LEDs for EVERY key - OLED display - Powered by a Raspberry Pi Pico - Auto polarity-correcting power input (because who has time to plug in power the right way?)

Some fun challenges I ran into: - Had to redo the PCB multiple times (always double-check your footprints!) - Learned the hard way about thermal management during soldering - Discovered that 100 LEDs can create some interesting signal integrity challenges - Found some microscopic shorts that only showed up when the board heated up (freezer debugging FTW!)

Currently, it's working with some bodge wires, though a few keys are still being stubborn. The case needs some tweaking, but hey, that's part of the fun of DIY, right?

Lessons Learned

1. Don't rush soldering - thermal management is crucial
2. Always verify footprints BEFORE ordering PCBs
3. When in doubt, add level shifters
4. Hardware debugging requires equal parts patience and creativity

Both projects are open source, and I'll be happy to share more details if anyone's interested! Let me know if you have any questions!

One of the difficulties I had with the camera app is that you couldn't leave the LED on for close up pictures to read off resistor codes. The magnifier app will let you manually leave the iPhone flashlight on, and set a fixed zoom if needed and save the controls layout so you can jump back to PCB inspection. The first picture is with the magnifier and the second is with the iPhone camera app. It saves you from needing to take a PCB to a microscope to figure out what was up with it. Also saves some disassembly to get the PCB out of whatever it is installed in. I was able to figure out the board at some point had been hand soldered with the wrong resistor value and that was the source of all our issues.

Me and my friend made this pcb that adds 2 bit with 2 bits and gives the result with 3 leds! It's the first pcb we design :)

Before building a full temperature controlled chamber for slow /"natural" temp variance... I'm trying to see how my Scale behave in various environnements ahah

im so proud making this :)

I made this dummy PCB on my 3D printer before submitting a front panel board to the PCB manufacturer. Turned out to be a nice method to avoid part alignment mishaps. The accuracy was in fact down to about 0.1 mm 💪

I had to add a bypass set of capacitors at the voltage divider that was feeding the + input of the opamp. I also had to add a low - pass filter on the signal input, especially if I attempted to use my phone as audio input it had a lot of noise on it and apparently the phone expects a somewhat low impedance or it will get even noiser.

I then also had to put a capacitor / resistor network across the feedback resistor to enforce lowering the gain at higher frequencies which prevented the opamp from oscillating during large signal swings.

And now it is fully functional, mounted to a heatsink.

Puts out about 14watts into 4 ohms at 30volts supply. Will do almost 20 watts into 2ohm load.

I will be switching the potentiometer out for a smaller PCB style one and also integrating the input filter directly on the board soon.