i assume the 12v is a -12 to 12 is a pulse as well as the 0-10v. it is not a hall efffect sensor.
12v is tach, 10v is speed. 4v is tps, 3v is map, 12v switches are simple enough.
the resistance values get me a bit. and i did leave one out. edited above.
i understand how the computer is looking at the sensor array and what they do, but as i am not well versed in EE, i have minimal knowledge of what the signals look like. references to metering and identification would be appreciated.
Still not answered the questions but I will see what I can do.
Basically the Arduino can only measure voltages of 0 to 5V with a 10 bit resolution. That means 1024 steps with a step size of about 4.88mV.
So to measure voltage outside this range you have to condition the signal. Normally this can be done by using two resistors as a potential divider.
Similarly for the resistance measurements. You have to turn these into a variable voltage before you can measure them. The ones you have are quite low and the normal use of a pull up resistor will cause a lot of current to flow. Do you know the current limit on these sensors? You might have to use op amps to condition this signal.
As to the speed, again the +/- 12V must be first converted to 0 / 5V, then you can use interrupts to make note of the timers each time the signals transit. Then you work out the RPM from the time between transits. You can do this to a resolution of about 2mS.
a visit back to ohms law.
I assume you are not measuring resistance, but in fact you are measuring the change (drop) in voltage, since current is constant. am i correct in this?
as far as the 12v switches, can i simply put a resistor to drop it to 5v? or would i need to drop it to 4? the current is constant.
sense of how he achieved the final result, the difference of measuring over a duration vs referencing a table with the length of time between spark.
as long as the board can deviate between some and no voltage, 2 resistors can do, like the other sensor (for both 0-10 and 0-12v). and it simply measures the peak
how do you mean averaged? i figure an average over 1/30 of a second will do. i know analog gages are simply fed the signal, like dumping water into a bucket with a hole in it. as far as a disply, i will be modifying off the shelf application to accept the inputs i can create.
Add together 50 readings and divide by 50 for example.
Or have a running average Moving average - Wikipedia
the difference of measuring over a duration vs referencing a table with the length of time between spark.
There is not much difference both give acceptable results for a display. There is no need to use a look up table with the latter as it is all linear and deterministic so a simple formula will do it.
between 2 sparks. engines are based on 720deg, suck/squish/bang/blow
10k off one plug would be 11.8 ms.
so the signal would be 5.9 ms per pulse. my car generates a signal based on this.
the link in another post walked through how they approached the measuring over a selected time and measuring each signal.