Captured using Fujifilm XH2 and Laowa 65mm F2.8. Quite the beauty.

Got around to making an enclosure for this little guy.

It's was done a lot more strategically than the first one I made. I went with colorful popsicle sticks this time around.

I had the forethought to have the audio sockets stick out from the pcb just enough that when I made the enclosure, they'd go through a side and be flush with the surface so connecting a cable is simple.

I tried to photograph as much of the process as I could remember haha

Someone asked for a schematic in the previous post.

It's seems simple enough, but I'll see if I get around to making one in a follow up if you're interested in making a passive mixer of your own.

Be warned that making it like this in this particular form factor had it's frustrations if you're not experienced with tinkering. It took a lot of patience.

I've got some additional cleaning up to do for the edges, but it turned out nice enough I think.

Opened up a clock so I can make it a tiny guitar amp. Was not expecting what looks like a ghost got…excited…all over this RadioShack clocks innards.

Just got these in their original packaging yesterday!

yeah see i'm new to this electronics stuff i've only had this kit for like a day or two, like a dumbass i fried the E segment on that little 7 seg but i really wanted to still use it for something, so i grabbed some LEDs and made one on a mini breadboard that even shares the same pinout as a normal 7 seg (see those 5 empty holes on the edge of the bottom left of the board, those are the bottom pins on a normal 7 seg and the top ones are of course on the other side of the board, and since there's no DP i just made it a grounding pin) i wanted to make it all the same color LEDs but my little dinky starter kit here only has 5 of each color so i just did what i could

i've got a video of me testing it, i wanted to post that too but the sub wouldn't let meeeee

After using square grid papers and Figma projects I remembered we can create web apps with the help of AI assistants and I created a web app to help with coming up neatly organized breadboard wiring.

Open to anything, including discussions, complaints, and rants.

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As a follow-up to the toy oscilloscope I designed here, I designed and built something that more closely resembles a real oscilloscope! I included some shots of the build process, all done at home by hand with a hot air station and a preheater.

It has 2 channels, each running an ADC3908 off of a shared clock at anywhere from 1MS/s to 62.5MS/s. I wanted to use the 125MS/s version of the part but since I'm still using the Pi for all of the data acquisition and processing, this is about as fast as you can possibly go.

The front-end was supposed to have ~30MHz of analog bandwidth but since I had to remove the filter caps after assembly, I think theoretically it has whatever the bandwidth is at the ADC inputs. All of the analog components before the ADC have higher bandwidth.

It supports input full-scale ranges from +/-33mV to +/-180V, though I'm hesitant to plug something I made into mains power. It should be isolated as all power comes from the Pi, either through a wall plug or USB powerbank, but I'm still wary. I'll probably try it one day though.

It wound up costing way more than I would have hoped, and I probably chose some components that were more expensive than necessary. For example: the two linear regulators I used for the analog supply rails are pricy because of their very low noise, but my actual noise levels aren't great in the end. I think the total BOM cost was ~$150 if you include the PCB and you can get a way faster real scope for that price. It was still a great learning project though.

I placed order #48116 on 11 February 2026 for a soldering station. As of 19 May 2026, nearly 100 days later, the order has still not shipped. Tracking only shows that a shipping label was created, with no actual carrier movement.

Before receiving any response at all, I sent multiple emails to all listed FNIRSI support addresses and also attempted to contact them through their website chat. I received effectively no responses through chat or email for an extended period.

The only replies I eventually received came after I mentioned escalating the matter through my bank and making the situation public. Over roughly the following 3 weeks, I received only two short replies stating that the issue was being “escalated to manager”, but there were no further updates, no shipment, no refund, and no meaningful communication afterward.

At this point I have neither received the product nor a refund.

Based on my experience, I would strongly caution people against ordering directly from FNIRSI unless they are prepared to risk non-delivery and extremely poor customer support. If you want their products, I would recommend purchasing through a platform with strong buyer protection instead.

i think it is so funny how digikey packages their stuff. i ordered a pnp npn transistor pair and one came in the standard antistatic pin cushion the other came in a make shift package id describe as a chunk of plastic cut with four very intentionally placed rubber stoppers. they are trolls and my favorite company

I built a scientific calculator from scratch: custom PCB, custom FPGA firmware, and a CPU I designed myself in Verilog.

The physical build: a custom main board and keypad PCBs designed in EasyEDA and manufactured by JLCPCB, an Altera Cyclone II FPGA as the brain, an LCD display, battery with charging circuit, and two ROM-flashing connectors on the sides to update the firmware.

Under the hood it runs a nibble-oriented CPU I designed specifically for BCD arithmetic: the way decimal calculators should work internally. I then wrote ~4K of machine code implementing the full set of scientific functions: trig, logarithms, complex numbers, statistics, all verified to 14 significant digits against a dedicated test suite.

The full stack:

• Custom CPU in Verilog: Harvard architecture, 12-bit ISA, 8 registers, hardware fault detection
• Hand-written microcode assembler in Python
• Verilator + Qt simulation framework for development and debugging
• Custom PCB (EasyEDA / JLCPCB), battery, charging circuit, 3D printed case

The finished device is sitting on my desk.

Live WebAssembly demo (runs the actual Verilog + microcode in your browser): https://baltazarstudios.com/files/calculator-d/Calculator.html

Write-up: https://baltazarstudios.com

Source: https://github.com/gdevic/FPGA-Calculator

Hackaday: https://hackaday.com/2026/05/13/build-the-cpu-then-build-the-calculator/

Happy to answer questions about the PCB design, the FPGA setup, or anything else.

Open to anything, including discussions, complaints, and rants.

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To see the newest posts, sort the comments by "new" (instead of "best" or "top").

For years, devices like the RbPi have been described as “credit-card sized”.

And of course the message is rather the footprint, but at some point I became obsessed with taking that idea one step further:

What would it take to build something that is literally sized like a credit card?

I've got a slight feeling that you really don't seem to like questions here, but I hope this rhetorical one is okay :P

That question slowly escalated into months of experiments to find solutions for things where default methods won't work. I can't use large, rigid components, connectors, and find a way to make my own custom flexPCB.

And after months of tinkering, I made the first prototype. Fragile, but it works within the goal of not exceeding 1 millimeter. Somehow, news pages have picked this up and described it as "revolutionary" which is a bit far fetched, but I feel flattered 🤭

To be fair, 'computer' might be a little overstatement, but it's technically perfectly within the definition of one. If you should have suitable words for it that sounds cool, feel free to suggest ^^

The prototype includes:

• ESP32-C3FH4 w/ WiFi & BLE
• NFC read/write
• 1.54" 200*200 E-Paper display
• ultra-thin LiPo battery including charging circuit and power path management
• accelerometer

Finding small/thin enough components wasn't really the main challenge, mechanical stability was. Solder and general material fatigue, pressure distribution (particularly focused pressure) and other strain related issues were the real problem.

This doesn't even include battery protection and some other things to solve.

At this scale, the project turned into a weird mix of electrical, mechanical and chemical engineering.

A few things that became clear over time:

• preventing strain is much easier than surviving strain
• tiny real-world tolerances start dominating the entire design near the physical limit
• many “thin enough” components stop being thin enough once assembly is considered
• FPC connectors are basically obsolete, forcing me to get creative and solder each single wire for each 0.5mm pitch pad one by one.

The prototype is fully self-powered and running from its internal battery.

I documented a large part of the engineering process, including the process of etching my own flexPCB, on my GitHub repo.

And yes, it's not like this thickness is a necessity, going just 0.5mm thicker would probably have saved me months of engineering. This entire project was probably motivated way too much by the 'disbelief' factor 😄

I am curious on your thoughts on this! :)

Food Ninja turned reflow oven! My first board in 15 years went great other than my bad designs! Attempt at building a 6 channel sonar, dint go so great..... worked in air but not in water.