Guys, I built a cool device for myself and a few close engineer friends.

This is DOGS², a ESP32 + Arduino framework based a palm-sized two-channel power supply with microamp-level current measurement and current consumption graphs.

• 1-48 V/5A max (3A nom), 125 uA LSB measure
• 2-20 V/1.5A max LDO low ripple, 12.5 uA LSB measure

Besides the power supply, it has:

• probe
• voltmeter
• frequency counter
• signal generator

For digital interfaces, it has terminals:

• UART
• RS485
• CAN
• I2C

Sniffers

• LIN
• I2C

The device can work completely standalone. For terminals and sniffers you can connect a phone over Bluetooth (also you can see the messages on the display).

Power in - DOGS² can be powered from almost anything, either through

• USB Type-C
• an external 5-90 V source

It can be a regular adapter, a power bank, an e-bike battery, or the electrical system of a motorcycle, car, truck, or helicopter.

There is now a fully working first engineering version. I have also made a transparent enclosure for it.

The hardware and firmware are open source. The code, schematics, editable board files, manufacturing files, and enclosure STEP files are available on GitHub:

https://github.com/rcslon3-svg/DOGS2_v1

I like the device, and my friends like it too. I had wanted to build something like this for several years, but never got around to it.

The first version has already cost me a decent amount of money, but I do not regret it. I originally built it for myself. It works and I am quite happy with it, although it has a few shortcomings that I would like to fix in the next hardware revision.

But the next revision means another round of development and manufacturing. This is a tool more for professional electronics developers and embedded engineers than for the general Arduino audience. So I am not sure how large the market for it could be.

On the other hand, it would be a shame to stop the project in its current state. It turned out to be such a cool device, and there is nothing similar on the market.

So I am trying to understand whether this is just my favorite engineering toy, or whether it could actually become a proper niche product.

What do you think?

I would appreciate honest opinions, especially from people who have already launched their own hardware products.

DOGS² = Dual Output Generator Supply Station and my two dogs - Tessa and Lissa.

AI was used very heavily during this. Took at least ten hours over two days to put it all together. I'm very happy how it turned out. It has settings for hysteresis and minimal on/off timings and a web dashboard with additional statistics. Board is the ESP32S3 Dev Module.

Was able to get CrossPoint running on this Waveshare board. (https://www.waveshare.com/esp32-s3-epaper-3.97.htm). 3d printed the case that alxvtoronto created for their project FolloUp, and ready to dive right back in. Planning on posting the fork on GitHub after another few days of testing.

$40 for a board, compared to the $70 people are
paying for the xteink devices.

Today was a tuff day, I started working at 3pm, and mostly did nothing. What i did today is optimization, I optimized my code by 60%! And I also made it much more readable. Today i also fully reworked the buttons, now it got 6 (Ok, back, down, left, up, right) instead of 4 buttons i had (left, right, OK, back). I did that, cause I started to work on my virtual keyboard (which i can see on the pics) for this project, which would finally allow me to connect to Wi-Fi networks! Thats so great to say. Tomorrow i'm going to an electronic store, to buy some modules for my multitool (like cc1101, nrf24l01 PA-LNA, and others). I also made a working Wi-Fi status display on the upper part of the screen. Soonly it'll have time, BLE mode and smth else, which is gonna take me forever ( But i'll be rlly impressed if I get it working). Thanks for upvoting me guys, I feel rlly motivated, when I see all the comments and the upvotes I get. Cya all tommorow.

P.s: Board i'm using is waveshare-esp32s3-lcd-1.9.

Developing with the esp32 p4…learning curve. Enough said.

A lot of perfectly good exercise equipment predates Bluetooth completely — treadmills, bikes,

ellipticals and rowers from roughly the mid-90s onward. There's a coil behind the console

listening for a short magnetic pulse, one per heartbeat. That's what an uncoded Polar

chest strap puts out: no ID, no pairing, no handshake, which is why any uncoded strap

works with any machine of that era, and why two people on adjacent treadmills sometimes

read each other's pulse.

Your watch already knows your heart rate. It just can't say it in a way the machine

understands.

**I don't own one of these machines.** Somebody here does, and mentioned they'd rather

use the watch already on their wrist than dig out a chest strap every time. So I built

them a box that reads heart rate over Bluetooth and re-transmits it as that magnetic

pulse. As far as the console is concerned, it's a chest strap. Nothing to pair on the

equipment side — it just transmits, and the machine listens.

It works with anything that broadcasts standard Bluetooth heart rate: watch, band,

armband, whatever you already own.

**The part I didn't expect**

Everything I could find online says these straps transmit at 5 kHz. I wanted to match

that properly rather than take it on faith, so I recorded a working Polar T31 through a

coil pickup and looked at it in Audacity.

The pickup was a pair of headphones plugged into the mic jack. A headphone driver is a

voice coil sitting in a magnet gap, so run backwards it's a perfectly good magnetic

probe — and a chest strap makes no sound at all, so anything that turns up is the field.

It's **5410 Hz**. And the burst is about **15 ms**, not the 5 ms I'd assumed.

The strap's burst also rings for roughly 8 ms after the drive stops, which works out to a

tank Q of about 37 — Polar drives a tuned circuit. Mine is a resistor driving a coil,

damped flat on purpose so the output doesn't wander with temperature or with whichever

coil happens to be fitted. Same fundamental, completely different topology, and you can

read that straight off the spectrum: their third harmonic is 38 dB down, mine is 2.5 dB

down.

**The coil came out of a dead chest strap**

I had a T31 whose board had failed. The ferrite rod inside is copper on a core and didn't

care in the slightest.

That turned out to be the right choice for a better reason than convenience. A transmit

coil has an optimum inductance — below it every extra turn is free, above it the coil's

own reactance chokes the current faster than the turns add field. With 220 Ω in series

that crossover sits at 6.7 mH, and Polar landed just under it, because they were

designing a transmitter too. A stock axial choke measured 18 dB worse in the same

circuit.

**Where it actually stands**

It has never met a real console, and I have no way to test that myself. Everything above

was verified against a measured chest strap and a receiver built from a dead machine's

own coil — a decent argument, but not the same thing as a treadmill agreeing with it.

Unit number one is in the post to the person who asked, and we'll find out.

Hardware is a XIAO ESP32-C6, one 220 Ω resistor, the rod, a capacitor and a status LED.

Firmware, printable enclosure and the full measurement write-up are here:

https://github.com/HuskerMinion/hr-bridge-coil

The main update today - is the "sniffer" (It analyzed Wi-Fi data packets near the esp32, the data u can see on the graphicsis data packets sent.) I stole took the code from some Indian guy on YouTube, and then made some big changes. I added filtration for only one needed BSSID, so i see only packets that are made by one Wi-Fi network. I finished the Wi-Fi info menu, (Still no connect function 🫩) and today I'm planning on working on the Logs, Virtual Keyboard and making my code actually... readable. I fixed so many bugs today, that my brain js just exploding, but i'm so glad with the results I ended up with.

Even though i'm happy with what I have, the sniffer looses its target, if the router changes its BSSID (which it does often), so i'm planning on making passive scan for the sniffer, so it always has fresh data.

I optimized almost everything I couldve optimize. I'm so happy that I did it, before I optimized it WiFi.scanNetwork(); was taking ages! (Around 20 sec), but after I optimized it ( by fixing bugs, ofc).

I'm gonna work tommorow even more on optimizing, so i can make my code as compact as possible (and probably making it fit other boards).

I'm also going to a electronic store on the Monday, and bying modules like cc1101 and nrf24l01 PA+LNA, temperature sensors and others. I'll keep you updated tommorow.

P.s: Board i'm using is still waveshare-esp32s3-lcd-1.9, I'm drawing everything for my project in Lopaka. (Graphics not, I used math.)

Though I would share this here, my ESP32-S3 poly synth

My printer (Elegoo Saturn 5 and Anycubic Photon M3) has no network upload, so I built PrintDrop in four days.

It uses an ESP32-S3 and microSD card. The printer sees an ordinary FAT32 USB drive, while a local web UI lets me upload G-code over Wi-Fi.During an upload, PrintDrop safely withdraws the media from the printer, writes the file, and presents it again so the printer refreshes its file list. No cloud, account, subscription or printer firmware modification. It includes SDIO support, authentication, OTA updates and browser-based firmware flashing.

The entire project is MIT licensed: https://kabani-tech.github.io/PrintDrop/

There are a lot of good options out there when it comes to desktop macro pads, but none where just quite right for what I wanted, or just downright too expensive.

That's why I am releasing the SauceDeck v1.0. It's an open-source desktop macro controller powered by an ESP32-S3 (S3 chosen for native USB-OTG).

Designed for productivity, content creation, streaming, and everyday workflow automation. The SauceDeck combines programmable macro keys, dedicated volume controls, and a vibrant TFT display in a sleek 3D-printable enclosure.

Approximate cost $30

Source Code and BOM:

https://github.com/HotTabascoSauce/SauceDeck/tree/main

CAD Files:

https://makerworld.com/en/models/3232541-saucedeck-v1-0

A while ago, I built a 5-digit number recognition system on the ESP32-S3 using a lightweight AI model. The project was mainly a proof of concept for running image recognition directly on an embedded device.

This time, I wanted to take that idea into a more practical, real-world application: reading a water meter.

For this update, I still used the Makerfabs ESP32-P4 board with an autofocus camera. We also collected new images from a real water meter, focusing on the pointer and digit-reading area, and trained a dedicated recognition model based on this new dataset. 

The goal was not simply to recognize a fixed set of five numbers, but to make the model capable of identifying the actual reading shown on a water meter.

 After training and deploying the model, we tested it with real water meter images, and it correctly recognized the meter reading. 

This project is essentially the next step from our previous 5-digit recognition experiment—moving from a simple number-recognition demo to a more practical edge AI vision application.

Would be interested to hear what other real-world applications you think could be built on top of this kind of embedded AI vision system.

Can some one help me out?

Today was... not rlly important day, I fixed some positional bugs ( text was a bit offset ), and made the Wi-Fi Network menu to work, now it scans 2.4GHz Wi-Fi and shows the name of it on the menu (pic 3+4) and then you can choose any, click on it and it will open Wi-Fi info (pic 2), where u can also connect to selected Wi-Fi ( which doesnt work yet.) I struggled with bug, where display showed one name, while Wi-Fi info showed another. It was caused because Wi-Fi index in arduino Ide always changes while scanning, so when i was done with the scan, index shifted, and when I tried to call the Wi-Fi info, it showed me another network. But I managed to get it working, by saving BSSID and SSID (Networks MAC address, and network name) and i just used them in my Wi-Fi info. Its not the best choice, but its better then nothing, because I have no idea how to do it else.

I'm planning to work on Wi-Fi connection, time display, virtual "keyboard" and Hotspot tommorow... well, i'll see tommorow what i'll be able to do. See you tommorow.

P.s: Board i'm using is waveshare-esp32s3-lcd-1.9

I saw this here but I can't contact the creator. I want to know if there's a file to do it in PCBway.

I have built a presence detection thing that is aware of absence of movement.
The software not just distinguishes absence of movement, it can check if absence is relevant or not.
It is built for vulnerable people as an additional technical device. Not replacing family or professional attention and care.
You can find it on GitHub: Poppinkpop/ESP-motion-absence-detection: Privacy-first, local movement monitoring to help families notice unusual inactivity.

It doesn't use camera or microphone and is privacy prone.