Juice Box is an open-source, programmable ignition controller designed around the Speeduino project. It is a DIY/low-cost alternative to mainstream ignition controllers on the market with the advantage of having additional IO for logging & tuning purposes.
I designed this ECU as part of my Triumph Spitfire restoration to convert it to a programmable electronic ignition system. It was created on a two-layer board that carries digital and analogue IO. From a trigger wheel mounted on the crank pulley, a signal is read by the ECU to determine crankshaft position. From this position data, the ECU controls a wasted spark ignition coil using inlet manifold pressure to determine spark advance. The ECU also supports auxiliary sensor data such as coolant temperature and inlet air temperature which help the user tune the engine.
I designed it with robustness in mind but to retain low-cost and availability for the DIY/open-source community. More details can be found on the wiki.
JuiceBox Features:
- Teensy 3.5 microcontroller support
- Compact SMD PCB
- Heavy-duty, high current capacity Molex connector
- Support for 1-8 cylinders, wasted spark
- Supports 36-1, 60-2 and other trigger wheel types
- On-board MAP sensor
- 6 analogue inputs for O2, inlet air temperature, throttle position, coolant temperature and 2 auxiliary
- 4 general-purpose digital inputs, 12V with over-voltage protection
- Cooling fan and fuel pump outputs
- 2 general-purpose 10A outputs
- Sensor calibration
- 16 x 16 ignition table
- Data logging
- USB
- Bluetooth
- CAN/OBD II support
Additional IO on the board helps support other functions. For example, O2 sensor readings can be used for carburettor tuning or the coolant temperature input can be used for controlling the radiator fan.