🔋 DIY Electronic Load

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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📂 What's Inside

• 🖥 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

• 📐 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.

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🎯 Project Goals

• 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 🚀

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🛠 Components Used

• 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

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Mermaid Diagram (rendered on GitHub)

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];

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⚡ Features

• 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

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⚠️ Disclaimer

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.

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🤝 Contributions

I don’t expect pull requests, but if you’re also into DIY electronics and want to share ideas or improvements – feel free.

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📜 License

MIT License – do whatever you want with the code and files, but don’t blame me if something goes wrong.