Slowduino is the fastest way to go from an inexpensive Arduino to a working EFI controller that plays nicely with the official Speeduino tooling. It keeps the same 16×16 maps, protocol, and tuning feel yet runs on an ATmega328p (Uno/Nano) while borrowing only the best ideas from the Speeduino firmware.
Slowduino is for DIY tuners, hobbyists, educators, and anyone who wants to build a full-featured ECU without the premium price tag. The project ships with ignition control, injection scheduling, sensor support, protective cut logic, and TunerStudio compatibility—everything you need to boot a motor in a garage, classroom, or lean workshop.
Slowduino board layout rendered for reference.
Injection and ignition wiring overview for the Slowduino board.
- Runs on Arduino Uno/Nano or Speeduino v0.4 hardware with the same peripheral set and protocol.
- 16×16 VE + Ignition tables, closed-loop narrowband control, and Speeduino-style CRC pages for TunerStudio.
- Deterministic Timer1-based scheduler keeps ignition/injection timing inside 20 µs even at 8 000 RPM.
- Full sensor stack: MAP, TPS, CLT, IAT, O2, battery, oil pressure, fuel pressure, fan, pump, and IAC.
- Engine protections inspired by Speeduino (RPM cut + oil-pressure monitoring) that gate fuel and spark when you need them.
Navigate the docs to learn how to build, tune, and extend Slowduino:
- Overview: What Slowduino is, why it exists, and how it compares to Speeduino.
- Technical Specifications: Hardware platforms, sensors, tables, timing, and EEPROM layout.
- Getting Started: Hardware list, firmware configuration, uploading, and basic calibration.
- Communication & Debug: TunerStudio protocol, serial diagnostics, and troubleshooting tips.
- Performance & Roadmap: Resource budgets, current limitations, and where we are headed.
- Contributing & References: How to help, disclaimers, and essential references.
Ready to flash a board? Start with Getting Started and keep this repo bookmarked for reference. Slowduino turns a generic Arduino into a reliable ECU—no custom silicon, no magic.