The purpose of this project is to make a simple Engine Monitoring System for Rotax 912 engine installed on ultralight aircrafts. Commercial product exist but are usually expensive. The functions of this system are: Tachometer, Total hours, CHT, Oil temperature, Oil pressure, Battery tension, Fuel level, Record of max values. This system can't replace standard instruments and the author of this project can't be responsible of any problem linked to the use of this system on an aircraft.
The system is directly connected to the engine sensors whose characteristics are described in the Rotax 912 Installation Manual (www.flyrotax.com). The tachometer signal is a pulse described in chapter 24-00-00 section 2.7.1. The CHT sensor is a variable resistance described in chapter 76-00-00 section 1.1.1. The oil temperature sensor is also a variable resistance described in chapter 76-00-00 section 1.2. The oil pressure sensor output is a 4-20 mA current from 0 to 10 bars described in chapter 76-00-00 section 1.3. The fuel gauge is a capacitive sensor (https://www.stratomaster.eu/lignes/mgl/pdf/Fuel_Level.pdf) with a 0.3V - 4V output.
The tachometer signal triggers an interruption in order to calculate the RPM. An internal timer counts the time. The total time of engine operation is strored in the EEPROM of the Arduino. It is recorded each time the engine stop and the total time change.
The information are displayed using a small 1.8" TFT (with some flickering issues) through several pages that the user can change using the push button.
This system is still in development and test and any help would be appreciated.