Hi.
A while ago i did graduate university of applied sciences, and as my coursework i did a Arduino which was monitoring cars boost pressure, engine coolant temp and engine oil temp.
I didnt do the programming myself, a buddy of mine did help me. I did use ebay sensors for each of these measurments, but i would like to go a little bit further.
I'm 99% sure, that it is possible to use sensors already on the car, so i need a little guidance.
I have a 96' car, volvo t5 engine, the ECT sensor has 2 wires and it changes the voltage according to temperature it's 1.6V for 20°C; 0.15V for 100°C.
The question is, can i hookup my Arduino to the sensor when its till connected to the ecu ? wont it hurt the signal going to the ecu ?
and maybe someone wanna help me with the code if this is possible ? i guess the code for temp reading is really, really simple ?
If you're absolutely positively sure that voltage will never go above 5V referenced to ground you could hook it up to Arduino A0 with a 10k resistor in series and run a test program to see what kind of numbers you get from the ADC, also, you'll need to connect Arduino GND to car ground. If the temp sensor is a thermistor it probably won't be very linear and will take some higher math to make a sensible reading.
void setup() {
Serial.begin(9600);
// put your setup code here, to run once:
}
void loop() {
// put your main code here, to run repeatedly:
Serial.println(analogRead(A0);
delay(500);
}
You should see somewhere around 325 at 20 degrees and fall toward 0 as engine warms.
outsider:
If you're absolutely positively sure that voltage will never go above 5V referenced to ground you could hook it up to Arduino A0 with a 10k resistor in series and run a test program to see what kind of numbers you get from the ADC, also, you'll need to connect Arduino GND to car ground. If the temp sensor is a thermistor it probably won't be very linear and will take some higher math to make a sensible reading.
Engine coolant temp sensors are all Thermistors...