This repository contains everything related to my homemade electronic load project.
It’s a personal DIY project – not a commercial or professional design.
I’m sharing it here mostly to keep things organized and maybe to help someone else who is experimenting with similar ideas.
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🖥 Firmware (ESP32)
Code for controlling the load, written for ESP32-C3 Super Mini.- No
delay()calls (uses timers/interrupts instead) - Online logging via MQTT broker 📡
- Current control via external DAC
- Calibration and basic measurement support
- No
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📐 KiCad Files
Schematics and PCB design made with KiCad.
Currently missing the 4-wire measurement module (will be documented later).
Expect changes and improvements over time. -
📝 Notes & Experiments
Test results, calibration data, and small helper scripts.
- Learn more about electronics, MOSFETs, and op-amps
- Build a useful tool for testing power supplies and batteries
- Experiment with current regulation, ADC/DAC, and firmware control
- Try 4-wire measurements for better accuracy
- Keep everything DIY-friendly and fun 🚀
- ADS1115 – external ADC (much more accurate than ESP32’s built-in one)
- MCP4725 – external DAC (better resolution and stability)
- 4x4 Keypad – for input
- PCF8575 – port expander for the keypad
- ESP32-C3 Super Mini – main controller
- LCD 20x4 with I²C module – display
- Case Z17 – enclosure
- 80×80×15 mm 2-pin Fan – cooling
flowchart TD
ESP[ESP32-C3 Super Mini]
ESP --> ADC["ADS1115 (ADC)"];
ESP --> DAC["MCP4725 (DAC)"];
ESP --> IO["PCF8575 + 4x4 Keypad"];
ESP --> LCD["LCD 20x4 (I²C)"];
ESP --> FAN["Cooling Fan (80x80x15, 2-pin)"];
ADC --> MEAS[Current / Voltage Measurements];
- Online logging with MQTT
- External ADC & DAC for better precision
- 4-wire measurement (documentation coming soon)
- No blocking delays in firmware
- Simple but expandable design
This is a hobby project.
I can’t guarantee correctness, safety, or reliability of the design or code.
If you decide to use any part of it, do it at your own risk.
I don’t expect pull requests, but if you’re also into DIY electronics and want to share ideas or improvements – feel free.
MIT License – do whatever you want with the code and files, but don’t blame me if something goes wrong.