Three ESP32 Rainbow Boards Failed QA ā Can we fix them? Iām assembling another batch of ESP32 Rainbows: PCB house does the boards, UV silkscreen and some parts, and I finish assembly and QA here in Scotland. I run through three QA failsāno sound, dodgy keyboard, and no USBāthen fix two: the audio fault was lifted pads on the headphone jack, so I bodged it back with flux and solder (speaker and headphones now work, but itās a spares board). The noāUSB issue was an ESD protection IC sitting off its pad; I reflowed it on a mini hot plate, cleaned up with IPA, verified continuity, and it now enumerates and... 02 January 2026
Christmas tree train! This thing is obnoxiously loud, so I crack it open and do a bit of surgery to tame the volume. If you want one to mess with yourself, theyāre on saleāand if you want to help me buy more nonsense, all the usual links are below. 02 January 2026
Stop Using printf() - Debug ESP32 the Right Way Right, letās give this a go. Instead of drowning in printf()s and blinking LEDs, I show how the ESP32-S3ās builtāin USB JTAG lets you hit Debug in the Arduino IDE (or PlatformIO) and actually step through code. We set breakpoints, add watch expressions, use conditional breakpoints, and even edit variables live with a simple FizzBuzz/LED demo. Itās quick, it works, and it beats āworks on my machineāājust mind realātime code and ISRs. Works on ESP32s with native USB. 02 January 2026
I Built My Own ESP32-S3 Boardā¦ And It Actually Works! I finally assembled my super simple ESP32āS3 dev boardāvoltage regulator, reset button, three status LEDs (5V, 3.3V, and a GPIO blinker), and all pins broken out. I showed two build methods: stencil + hot-plate reflow (quick, with a few USB bridges to clean up) and full hand-solder under the microscope, complete with the rigorous āsolidā test. Soldered the ESP32āS3 module (skipping the center thermal pad unless you need it), plugged in, got power LEDs, confirmed USB enumeration, flashed a blink sketch, and weāve got a blinking LED. Next up: turning this basic dev board into something more professional for production.... 02 January 2026
It blinking well works! Quick shout-out to PCBWay for the fantastic PCBs and SMT assembly. If you want to help me buy more nonsense and keep the projects coming, you can support the channel via Patreon, check out the shop, use the AliExpress/Amazon affiliate links, hang out on our Discord, and subscribe to the Atomic14 and MakerNews newsletters. 02 January 2026
I Built a 27V PCB to Fix This $3 Display... I resurrected the LCD writing tablet I blew up last time by designing a dropāin PCB that generates a 27 V pulse to clear the screen. Itās a regulated dualājouleāthief variant with two magnetically coupled 20 ĀµH inductors (soldered opposite ways), a 27 V zener for regulation, inrush limiting, and a few caps and a bleed resistor. I assembled it with PCBWay boards, tried both Volteraāprinted paste and manual SMD under the microscope, salvaged the blister button, and profiled it on the Nordic PPKāpeaks ~18ā19 mA, ~7 mA while regulatingātotally coinācell friendly. It fits with a bit of mechanical fiddling,... 02 January 2026
CH32V0003 Plays Mod Music I stumbled across cpldcpuās ModPlayRISCV and couldnāt resist diving inātime to squeeze some retro MOD tracker tunes out of a tiny RISC-V and share the fun. If you want to fuel more of this nonsense, thereās the shop, Patreon, Discord, and newsletters! 02 January 2026
How Is This 10Ā¢ Chip Talking? I got a 10ācent MCU literally talking. With just 16K of flash and 2K of RAM, I used PWM and a tiny transistor amp to play 6+ seconds of audio at 8 kHz by compressing it with superāsimple 2ābit ADPCMā4:1 compression and a decoder in under 2 KB. I built a handy WAVātoā2ābitāADPCM tool to make it easy. For longer phrases, I switched to the Talkie library (TI LPC speech synthesis from the TMS5220/TMS5100 eraāthink Speak & Spell and classic arcades), and I even made a web tool and player for generating and previewing LPC data. Itās wild what you... 02 January 2026
10Ā¢ MCU Brain Surgery - CH32V003 I crack open a punchy little toy, show how the original just squishes two contacts to light the eye LEDs off a pair of LR41s, then perform some brain surgery to cram in a tiny lithium cell and my own board that triggers lightsāand an incredibly annoying tuneāon each punch. It sips about 7 ĀµA in deep sleep and wakes via a yellow trigger wire, but the soldering was fiddly and full of swearing. Tape it up, cram it back in the head, and yes, it works a treatā¦ maybe too well, because the beeping is driving me mad. 02 January 2026
10Ā¢ MCU Music Hack - CH32V003 I spun some tiny WCH boards at PCBWay around an 8āpin MCU (48 MHz, 16k flash, 2k RAM) to beep tunes off a coin cell. I tried hand-soldering, then used my paste-dispensing PCB printerāexpired paste still worked great. Standby sips under 8 ĀµA, but it locks out programming; a WLink flash wipe rescued me. Wake draws ~3.3 mA, and audio peaks hit ~130 mA (~13ā14 mA average), which browned out the coin cell. A tiny 80 mAh LiPo with a TP4056 (modded to ~100 mA) proved the design, then swapping the buzzerās base resistor from 1k to 10k tamed it... 02 January 2026
ESP32 PDM Microphone - What do you do with the L/R pin? I treated myself to some hands-free probes and dug into the PDM mic on my ESP32 board. I was confused that the new I2S PDM API only asks for clock and dataāno LRCLKāyet the mic datasheet shows an LR/SEL pin. The trick: in PDM, LR is just a static select. Tie it low and data is valid on the rising edge; tie it high and itās valid on the falling edge, so two mics can share the same I2S lines by picking opposite polarities. I proved it on the scope and realized I donāt need to burn a GPIO on... 02 January 2026
ESP32-S3 USB UAC Audio Device - does it work? Time for an audio project: I took my PCBWay ESP32āS3 board for a spināfixed the common anode/cathode LED mixāup, verified the IMU and battery charger, then tested an I2S PDM mic and tiny speaker with a Web Serial Audio Studio (scope, spectrogram, tuner). I also turned it into a USB UAC device in ESPāIDF: the mic is clean, but speaker over UAC is crackly (Mac/Windows toggle oddity); direct I2S WAV playback is perfect, so the hardware passes QA. 02 January 2026
High Voltage Coin Cell - 27V Joule Thief How much voltage can we squeeze out of a CR2025? Turns outā¦ plenty! I built a little Joule-thief-style boost circuit with two 1 mH inductors, an NPN, a Schottky, a 27 V zener clamp, and a storage cap to zap my LCD pad clean at around 27 V. I profiled it with a Nordic power monitor: about 11 mA during the boost and ~9.28 mC per clickāso tens of thousands of presses from one coin cell. Then I added a second transistor tied to the zener to auto-limit the drive, dropping hold current to about 1.5 mAāhuge win. Scoped it... 02 January 2026
Super Easy ESP32-S3 Dev Board Making an ESP32-S3 dev board is way easier than it looks. I simplify the datasheet reference: skip the external crystal, wire native USB D+/Dā (pins 19/20) straight to a USB-C with 5.1k CC pulldowns, add a BOOT switch and an EN RC reset, and power it with an LD117 LDO thatās happy with ceramic caps. In KiCad I build the schematic with Espressif libraries, add LEDs for 5V, 3V3, and a blink GPIO, set up net classes, route a clean USB differential pair, stitch a solid ground plane, and label everything. Itās a bit wideājust gang breadboards togetherāand you end... 02 January 2026
Dodgy Circuit Defused - fixing the silly red thing. Iāve got all the bits to bring this little arcade game back to life: swapped the dead 3.3V regulator (had to buy 100ā¦ oops), tried and successfully revived the totally flat Liāion with a trusty charger board, and Iām adding a couple of Schottky diodes to handle USB vs battery power. Used the mini hot plate to reflow the regulator (not my finest soldering and, of course, the microscope didnāt record), confirmed 5V in and 3.3V out, and the screen actually boots. Next up: stick the charger board down with Kapton, wire B+/Bā to the test points, cut the right... 02 January 2026
Dodgy circuit could have caused a fire! So, I got this red mini handheld game thing from AliExpress and it died pretty quickly. After a bit of tinkering, I found that it still draws current but isn't turning on because of a dead battery and a burnt voltage regulator. I removed the faulty components and injected 3.3 volts directly into the system, and guess what? The screen lights up and it works, but there's no sound. Despite the hiccup with my microscope, which stopped recording some interesting bits, you get the picture. It's partly revived but not quite there yet. Big shout out to PCB way who... 02 January 2026
Forget the Arduino Serial Plotter - try this instead! Hey everyone! So, you're probably familiar with the Arduino serial plotter, right? It's useful for basic stuff, but I wanted something better, more cross-platform, and runs right in the browser. Enter the web serial plotter, using the web serial API! It's super flexible with zoom, export options, and light/dark mode. You can even pan through history or switch to absolute time. Plus, it's all secure and runs locally. It's open source, and I'd love your contributions or bug reports on GitHub. It's still a work in progress, but I think you'll find it pretty handy! 02 January 2026
Tearing Down a Bistable Cholesteric Display So, I finally tried out this bistable cholesteric display from my AliExpress stash after seeing Big Clive's teardown. It's super cool to play with, and I mean, it just clears up with a button press after you scribble on it. Gave it a whirl to understand the voltage involved and even ended up sparking it with some reverse polarity action (not the smartest move, I know). I might've broken it, but hey, it still sort of works manually. Check out Big Clive for a deeper dive into its reverse engineering, and remember to like and subscribe! 02 January 2026
This brings back happy memories Join me as I dive into the nostalgic sounds of dial-up internet, exploring how these iconic tones played a role in the history of digital communication. We'll decode the melodies that once connected us to the world, with insights and analysis that bring the era of dial-up back to life. 02 January 2026
This Number Does Nothingā¦ when you have native USB This video's all about how the baud rate setting on an ESP32S3 with native USB does absolutely nothing. Testing with different baud rates showed no effect on performance; every rate worked flawlessly. With USB full speed, you can expect data transfers of up to 7 megabits per second. So, baud rate? Totally irrelevant with native USBāit's full steam ahead, folks! Grab my test code from GitHub, give it a go, and share your results in the comments. If that blew your mind, don't forget to like and subscribe for more ESP32 insights! 02 January 2026
I Made a Digital Twin for my PCB - IMU Visualiser Hey everyone! In this video, Iām diving into testing the cool functionality of my new board that I designed, and demonstrating how to use both an accelerometer and gyroscope with my favorite little tool. The board is rocking an LSM 6DS3 sensor, which works like a charm, despite the tiny LED snafu from before (watch my 'ninja repair' in the previous video, haha). I walk through the different modes, including a fusion mode that magically blends sensor data for accuracy. Also, there's some cool 3D modeling in play where you can bring any model to life on my public website... 02 January 2026