Using a arduino as a car information display?

Hi

Recently i have looked at starting to buy a arduino, and a LCD screen for it.
The uses for it, would be to fxx, show temperature, air pressure, lambda(oxygen sensor) and such on a LCD screen, and to have some hardware buttons for my car pc.

Heres some info about the sensor that i might be using, and i would like some guides on how to interface:
Temperature sensor is just a NTC resistor
air Pressure sensor, 0-5 volt output, depending on the air pressure.
Lambda sensor, Analog sinus signal, 0-1 volt
Hall sensor, 5v or 12 volt output, for engine RPM.

Should it be possible for newbie, who never have programmed before?
And what arduino should i select, i have looked at the seeeduino MEGA, because of its many connections.

Best Regards

This should all be possible.

Many of the things you want to do has already been done, and you can find info and get help from others.

The only small prolem i can see is 12V from a hall effect sensor.

Arduinos analog in can only handle up to 5v, but it's merely a question of scaling down the voltage for instance with a voltage divider.

Any luck with using the hall effect sensor? I've been thinking about using one from sparkfun to try to count the ignition pulses, but have no idea how to do it...tape it on the spark plug cord? :stuck_out_tongue:

ive been looking into getting something like this:

but i dont know if i'll be able to read the serial (or bluetooth) output... i know i should be able to but i don't want to waste my money.

this would prevent you from having to interface with many of the standard sensors.

SImilar to rob's post, have you thought about using the cars OBD or CAN bus interface?
It seems like you would be making more work for yourself by connecting to individual sensors :slight_smile:

Any luck with using the hall effect sensor? I've been thinking about using one from sparkfun to try to count the ignition pulses, but have no idea how to do it...tape it on the spark plug cord?

Hall effect sensors react to presence of a magnet. The Hall effect sensor for rpm sensing is usually built into the car tracking revolutions of the crankshaft. Taping one to a spark plug lead probably wouldn't work too well.

Lambda with a narrowband o2 is pointless especially if your doing this with a forced induction car (turbo,supercharger)

You will get extreamly unstable readings as well as less than minimum resolution with the narrowband sensor.

Look into a wideband its a o2 sensor thats made to read more than the narrow window of ~14.7 afr which alltho many un-educated believe to be the optimum ratio for an engine which is so far from the truth.

The ONLY time a narrowband 0-1v 02 sensor is useful is while cruising in closed loop highway driving (roughly < %15 throttle ) to enable the ecu to try and achieve better fuel economy.

The wideband probes from Bosch and NTK, both can meassure a lambda value from 0.7 all the way up 3.0, and gives a much more accurate measurement, because it is digital, and the normal lambda probe is analog.
The way the wideband sensor works, is by using a pump cell(Ernst cell?) to pump air in to the sensor, so the air mix is the same inside the sensor as in the air outside the sensor, the Engine Control Unit(ECU) then can read how much amps that the pump cell needs, and what the voltage is on the sensor it self, this makes it possible for the ECU to calculate the Lambda value.
But a wideband would be pretty hard to wire up to a arduino, because the signal changes are really fast, and really small.
If you want to meassure ignition timing and maybe even get a timing graph, you can use a coil around the spark plug wires, and if the car has COP(Coil On Plug) then you can use a normal induction sensor from the crankshaft position sensor, to get a signal you can meassure.

Best Regards
Morten

I have looked into the narrowband lambda and it seems to work from 10 to 19 afr? Not linear, but still. Its simple and cheap.
I lineareized the output from a datasheet and cant see why it wouldnt be useful? Then i tempcompensated it on the low side (the high side isnt where I want to be...) and made a cyklic check to determinate if its only gas or if its etanol too. Purpose is a kinda squirt...
Is it something else than the output signal from a narrowband we have to consider?

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