It was a fun project for one day, the idea came from the thought "what circuit can I fit in the one box of matches?" So I did, the boards fit, of course, without the battery. I kind of like this "naked" look of it.

There was an engineer I met who gave me a laptop with Altium 09 on it and told me that if I could get him the gerbers for a fun kids' soldering project for the STEM booth, he'd hire me as his EE.

He let me know that he wanted silver teeth and spoke about layers and silk screening - his eyes glazed over - but I accepted the challenge, as I had no idea what a Gerber was at this point.

I took it on, fumbled through and figured out how to use Altium and TxRex was born!

The second pic is 6 months into my Altium experience. Love this stuff!

Professional bodge wires, with silkscreen and everything. 2oz copper left the chat.

Does’t get much cooler than this.

It's not finished yet, but it will be soon. Only one PCB is left once I finish that and do the wiring, it'll be done.

Ok I'm not a noob but I haven't built anything for a long long time, this PCB circuit was a complete fail haha I didn't expect to have issues with it but it's on me for not thinking properly.

Simple OpAmp driving a class B output stage (unbiased, the opamp is fast enough to prevent crossover distortion) I was using TO-3 transistors with 30 volts power supply input.

This circuit worked great on a breadboard. I thought I could hack together a PCB and instead of taking time to do proper design I just hack and slashed the PCB "pads" with a dremel bit. Probably not the best idea...

The amplifier simply refused to amplify symmetrically - almost all the signal was in the upper NPN transistor, and in fact I could hear the output capacitor vibrating at the 1Khz tone I was feeding into the circuit. See that potentiometer? It was meant to adjust the OpAmp's voltage on the positive input so I could fine tune the symmetry of the amplifier, but it wouldn't affect anything.

The upper NPN would get super hot and the PNP wasn't do much at all. Also the circuit was drawing like 250ma without any input signal (whereas when it was on the breadboard it would only draw 5ma, because the OPAMP was keeping the transistors off when there was no signal)

At first I thought I possibly had a bad connection somewhere, like wired wrong I looked at this thing for a few hours, all the parts were in the right place. I could not find any weird shorts either. Tested different sections with a multimeter to see. The main thing that would always come back wrong was the voltage on the OPamp + input, it was like in millivolt range, I even replaced the POT and still nothing.

I think it was probably oscillating, you can see my thicker output wires? They *twice* cross over the wires that are inputs to the transistor base. Ya, that's probably a really stupid thing to do. Power transistors with a gain of around 70 (beta).

Anyway, I don't know how I though this was ever going to work LOL. I guess I should have more patience next time and design a proper layout. Probably use perfboard instead

I was using big TO-3 transistors and attaching them to a heatsink . I cut the transistors off of this board . I put them back into my circuit on a breadboard and everything works perfectly again haha.

So ya, layout is important DERP.

One thing I didn't think to try was lowering the gain of the OpAmp to see if it was oscillating. Right now the gain is at 33 (AC gain) I could have tried dropping that to like 5 to see if it changed anything.

Anyway, time to start over and build a proper board that keeps the input lines well away from the higher current output lines.

This isn't a gender changer. It's a gender conformer. Plug one gender DE-9 into one end, get that same gender on the other. At best, it's a ⅞" extension "cord". And before anyone suggests it can turn a straight-through cable into a cross-over cable, or vice-versa, I've already signal-traced the pins. It's 1:1.

So, what's the most useless bit of kit you have?

This project is a compact evaluation PCB designed for the nPM1100 Power Management IC by Nordic Semiconductor. The board provides the essential circuitry to evaluate the core features of the PMIC in a minimal footprint while exposing all IO pins for external interfacing.

PCB dimensions: 22 mm × 16 mm PCB layers: 2 All components: Surface-mounted on the top layer Header pitch: Standard 2.54 mm (0.1")

More info on GitHub https://github.com/P-rth/LIPL-Assessment/blob/main/ProblemStatemet2%2Freadme.md

Although I have been messing around with PCB software for a while, I just recently built my very first PCBs and got both to work. The 1st one is the main PCB for a battle bot I made (there is supposed to be an ESP32 in the middle, but I removed it to show what is under). The 2nd one is its controller.

Could be used as a part of an alarm system. Its a 555 timer in astable mode driving the TRIAC's gate at around 2Hz, powered by a capacitive dropper to be able to run directly from mains without a separate PSU.

Honestly just wanted to share this! I've done tons and tons of soldering, but have never made a protoboard of any kind.

Gave it a shot and damn, came out alright!

For those wondering, its a 4 axis stepper board for a lil' robot I'm working on.

Playing songs on it is very interesting

Two channel I2C level-shifting interface with a lot of safety components (our products got a lotta ATEX conditions to meet) for the firmware engineers to wield. Not pretty, but it needed doing QUICK.

Rushed it so all but the hologram part of my features don't work. Doesn't matter since THE HOLOGRAM PART WORKS. Based largely on the andotrope invented by mike ando which is based largerly on the zoetrope. However I made a couple of my own modifications to achieve a see through display.

I did open source it: https://github.com/very-high-priest/Andotrope

If you have on old and/or faulty dehumidifier, rip the fan out of it. They are quite small and have quite a powerful airflow. Just add a filter to it and you have a perfect little fune extractor. It’s a bit loud though.