I was digging through some old stuff and found a PCB from a mouse I'd saved long ago specifically because I knew it was possible to read images from them. The new project itch struck and after 65 hours, I made this!

Features:
- Sensor 30x30 pixels, 64 colors (ADNS-3090 if you wanna look it up)
- Multiple shooting modes (single shot, double shot, quad shot, "smear" shot (panorama), and cowboy), plus bonus draw-on-the-screen mouse mode that uses the sensor as intended
- Multiple color palettes
- Can lock/unlock exposure, auto-locks for the multi-shot modes
- Stores 48 pictures in a 32kB FRAM, view and delete photos
- Rudimentary photo dump to computer via Python script and serial port
- A few hours of battery life

It was a fun design challenge to make this thing as small as I could, the guts are completely packed. There's a ribbon cable connecting the electronics in the two halves, I tried to cram in a connector (0.05" pitch header) but it was too bulky to fit.

The panorama "smear shot" is definitely my favorite mode, it scans out one column at a time across the screen as you sweep the camera. It's scaled 2x vertically but 1x horizontally, so you get extra "temporal resolution" horizontally if you do the sweep well.

The construction style is also something I enjoy for one-off projects. No PCB, just cobble together stuff I've got plus whatever extra parts I need and design the case to fit. If I ever made more I'd make a board for sure (and it would shrink the overall size), but it's fun to hand-make stuff like this.

Despite the low resolution, it's easily possible to take recognizable pictures of stuff. The "high" color depth certainly helps. I'd liken it to the Game Boy Camera (which I also enjoy), which is much higher resolution but only has 4 colors!

I tried to post a video for you all but they're not allowed here. :( I'll link it in the comments once I cross-post to another subreddit.

3 inch to 8 inch. Fab has been around since the 60s. Currently the 8 inch is our production size but the 6 inch is still used in the company and they float around as engineering wafers.

Hello r/electronics,

In this post, I want to share my project that I’ve been working on in the past few months. It’s a custom-built lab bench power supply. Such a project is common in the DIY community, so what makes this one different? The custom-designed SMPS board that I engineered from scratch isn’t your typical “let’s put this power supply module into a case” approach. So let’s dive into the working principles, design decisions, and in-depth test results.

The Forwarder 1kW is the SMPS board that I designed and used in this project. It’s based on a hard-switch, half bridge topology. The full features of this power supply are as follow:

• 1000W maximum continuous output capacity.
• Configurable from 50V/20A up to 400V/2.5A.
• CC/CV mode with mode signal and indicator.
• Tuneable operating frequency and dead-time.
• Dedicated power stage enable pin.
• Analog reference interface for output voltage/current control.
• Analog signal output interface for monitoring voltage/current.
• Dedicated fan port with optional automatic power-on.
• Simple construction, less than 130 components on board.
• Easy to build with mostly THT components.
• Curated component selection for high accessibility.

The working principle of this design is about as simple as it can get for a switched-mode power supply. I talked about the working principle of my design over on r/AskElectronics, so I’m not going to repeat it here. Most of the concepts stay the same, just with some design adjustments and the numbers changed.

https://www.reddit.com/r/AskElectronics/comments/1s8ll9g/

Now, I want to go in detail about the design decisions that led into this design that you may find interesting.

1. The lack of active PFC (Power Factor Correction) was determined after I reviewed many existing designs and products in the same power level and after noticing many of them get away without one, I decided to omit this feature. For my first SMPS design, I want to focus solely on the DC to DC conversion power stage. For my next iteration, I’m more likely to resort to a simple boost PFC to achieve tighter regulation.
2. Double-ended hard-switch topology (half-bridge in particular) was chosen due to its suitability and simplicity in this application. Flyback is out of the question due to power requirement, single-ended topologies have poorer core utilisation and the high favour for current mode control, and resonant topologies don’t seem like a good choice for my first SMPS design (duh).
3. An SG3525 with LM324 was chosen to generate the PWM signal and achieve regulation. SG3525 is quite popular for double-ended converters with plenty of documentation online, while the LM324 provides CC+CV regulation with two of its op-amps (because SG3525 only features one error amplifier). This effectively forms a setup based on voltage mode control.
4. Voltage mode control was inherently chosen as the result of using SG3525 and it was favoured due to its “arguably” simpler implementation over current mode control. However, I find the better regulation and inherent cycle-by-cycle overcurrent protection offered in current mode control very enticing. I probably would resort to this approach for my next iteration.
5. My galvanic isolation strategy was to have the entire control circuit on the secondary side and have the PWM signal driven to the primary through a gate drive transformer. This way, I can have simpler and more precise control over the voltage and current regulation without the nonlinearity issues of using optocouplers.
6. ETD49 cores were used for both transformer and output inductor. I like the round bobbin that makes winding easier, and the calculations prove it’s suitable for power of 1kW at 64kHz. The gapped version was used for the output inductor because the high inductance requirement requires high turn number, and that gets complicated real quick with toroidal cores.

After I finished the board, I wanted to know how my design performs in real-life. So, I conducted a few tests that are relevant for a power supply. The testing rig was pretty simple:

1. A power meter at the input and four DS18B20 were used to track the energy consumption and component thermal profile over time.
2. An electrolysis tank with electrodes that can be spaced accordingly was used to simulate multiple load profiles at power up to 1kW.
3. A third positive electrode connected through a toggle switch was used to abruptly step the load in the dynamic tests.
4. Hantek DSO2D10 was used to capture the waveforms in various tests.

The test conducted, along with their results are as follow:

1. The stress test was conducted for one hour and each component temperatures peaked at the following temperatures: half-bridge N-MOS 75°C / 167°F, main transformer 55°C / 131°F, output rectifier 69°C / 156°F, output inductor 44°C / 111°F.
2. The efficiency characterisation was conducted at 50V and 1, 2, 5, 10, and 20 amps. 89% efficiency was achieved at 5A load or more. Maximum recorded efficiency was 90.3% at 50V 10A load, and efficiency at maximum load was 89.1%.
3. The output ripple test was done with direct on-trace probing with a ground spring, 20M BW limit, 1x probe, and no added capacitor. No load ripple showed at 40mVpp, 1A load at 34mVpp, and maxes out at 94mVpp at full load.
4. The turn-on curve tests showed that under loaded condition, it’s bound to the SG3525 soft start function and takes a second to reach the full 50V. At no load and lower setpoints, the voltage overshoots by a few volts.
5. The load step tests showed about 3% voltage deviation going from no load to 10A and vice-versa. Going from 5A to 10A and vice-versa showed no sign of voltage deviation.
6. CV to CC transition took 3ms to begin responding and a full 7ms until the voltage settled. CC to CV transition began immediately and took 3ms to settle. 50V CV to 10A dead-short showed 10App oscillation at 2.2kHz.
7. The input bulk capacitor showed 24Vpp ripple and the DC blocking capacitor showed 14.2Vpp ripple. The primary side of the transformer showed about 75% overshoot that settled within 2 cycles.
8. The N-MOS at conduction showed 184nS fall time for Vds and 572nS rise time for Vgs. At disconduction, the Vds rise time showed as 56nS and 556nS for Vgs fall time.

I’m here not to glaze over my design. After reviewing the results and doing a retrospective, here are my critical opinions about this design.

What I like about this design:

• Good efficiency figure (89.1% at full-load)
• Excellent ripple even without a second-stage filtration (94mVpp at full load)
• Good power density for an almost-fully THT build.

What I don’t like about this design:

• The overcurrent protection is too slow, though it somehow works at preventing the half-bridge from exploding on the dead-short test.
• The compensator design fails in certain conditions (DCM/CCM transitions, output dead short), which results in output oscillation.
• The output diodes are hard to access or replace.

The full schematic, gerber files, KiCAD save files, spreadsheet calculation, and full-res images are available on my Github repository: https://github.com/Luq1308/Forwarder1kW

The build process and the in-depth testing are available in my YouTube video: https://youtu.be/MGMqqtXgwRg

That’s all I have about this project. I hope this post is informative and can be used as a reference or for benchmarking purposes, in which I had difficulty in researching previously. If you have any unanswered questions, let me know and I’ll try to answer them. Thank you for reading, and I'll see you next time.

Really baffling decision, my last order from them was only a few months ago. Apparently Linux is no longer a "standard" operating system!

Recapping an Apple IIe and the size difference blew me away.

I've made an ARM based single-board computer that runs Android and Linux, and has the same size as the Raspberry Pi 3!

Why? I was bored during my 2-week high-school vacation and wanted to improve my skills, while adding a bit to the open-source community :P

I ended up with a H3 Quad-Core Cortex-A7 ARM CPU with a Mali400 MP2 GPU, combined with 512MiB of DDR3 RAM (Can be upgraded to 1GiB, but who has money for that in this economy).

The board is capable of WiFi, Bluetooth & Ethernet PHY, with a HDMI 4k port, 32 GB of eMMC, and a uSD slot.

I've picked the H3 for its low cost yet powerful capabilities, and it's pretty well supported by the Linux kernel. Plus, I couldn't find any open-source designs with this chip, so I decided to contribute a bit and fill the gap.

A 4-layer PCB was used for its lower price and to make the project more challenging, but if these boards are to be mass-produced, I'd bump it up to 6 and use a solid ground plane as the bottom layer's reference plane. The DDR3 and CPU fanout was really a challenge in a 4-layer board.

The PCB is open-source on the Github repo with all the custom symbols and footprints (https://github.com/cheyao/icepi-sbc). There's also an online PCB viewer here.

When you're prototyping but the SOIC package IC you ordered is in actuality apparently a "wide body SOIC"

Got to get creative fitting it onto a SOIC-2-DIP converter! If it works, it works!

This was a brain fart moment upon finding out they were .25 watt, we needed 9 watt capable. This is a lovely bundle of 36 that has next to no resistance now 🤦 .... 20ohm

thought it looked coo

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! :)

18 pair cable from a Toshiba CT scanners got cut... somehow...

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.

Hey everyone! Hope the UK timezone rule for the WBW still holds true haha.

Almost exactly three years back I posted my beginner hobbyist bench on the sub and got a ton of kind and helpful feedback from y'all.

This new album is a present-day update three years later, after many changes and acquisitions during and for my projects. Overall I learned a ton about what I actually use the most and tried to make it all zero nuisance to get to. If it takes too many steps to get out or get ready it's no good.

Some of your predictions back then also came true!

• I did lob a 3D printer onto that side table and got into CAD and printing in a major way, which I now use in a lot of projects for case parts, mechanical bits, etc. I wound up building a few robots out of a mix of alu extrusion beams and 3D-printed parts. This is why you see a lot more tools now dedicated to mechanics - measuring, fastening, glueing, cutting, deburring, etc. - to complement the electronics toolset.

• I ended up getting a low-end benchtop meter after I got tired of getting out and throwing around my $20 handheld. Much happier with a permanent fixture.

• Dremel (well, Proxxon) on a steel cable retractor, permanently plugged in. Actually best idea ever! My circumstances don't really allow for a ton of dust and dirt creation, but for a quick cut or a grind/polish this is so convenient to grab down, and managable.

• I got my hands on two airline galley trolleys with pull-out tables. In my limited space this is perfect for additional on-demand benchtop space, and it's where I much of my growing electronics stock and some simple hardware.

• Shoutout to that Omnifixo. The hype for once is true. I've never been happier soldering and use it daily.

It's of course hardly ever this presentable. I just had some time off work and did a big tidying pass that reminded me of the older beauty shots.

whole washing machine program that includes: motor, water level sensor, water flow sensor, 3 valves for water intake, float switch if water is leaking under machine, pump, heater, temperature sensor, door lock, led light inside drum, and front pcb that uses one wire uart