Arduino Nano Project Questions

Hi Phil,

If this is a vehicle, keep in mind the nominal 12V signals can be as high as 14.4V when the vehicle is running, so your voltage dividers on "12V" sensors should reduce 15V to 5V (for a little safety margin).

To amplify an analog signal from 5V to 12V you can use a non-inverting op-amp circuit such as in this app note:

http://www.ti.com/ww/en/bobpease/assets/AN-31.pdf

I would regulate the 14V battery to 12V with a low dropout regulator to supply voltage to the op-amp which would need to be a rail-to-rail model.

The Arduino would use a 5V regulator.

Magnetic pickup output voltage varies with gear speed and physical gap and different models output anywhere from zero to 200Vac, usually at least 7 Vp-p. They all output AC voltage, unless there is built-in circuitry. If there is no built-in circuitry, you can convert the AC signal to DC pulses using a diode to only pass the positive phase of the AC signal followed by a resistor and 4.7V zener diode to clamp the maximum to 4.7 volts. More sensitive circuitry is possible, but also more complex. This digital pulse signal may need to feed an interrupt pin or a counter.

Doug

Hi Phil,

If this is a vehicle, keep in mind the nominal 12V signals can be as high as 14.4V when the vehicle is running, so your voltage dividers on "12V" sensors should reduce 15V to 5V (for a little safety margin).

To amplify an analog signal from 5V to 12V you can use a non-inverting op-amp circuit such as in this app note:

http://www.ti.com/ww/en/bobpease/assets/AN-31.pdf

I would regulate the 14V battery to 12V with a low dropout regulator to supply voltage to the op-amp which would need to be a rail-to-rail model.

The Arduino would use a 5V regulator.

Magnetic pickup output voltage varies with gear speed and physical gap and different models output anywhere from zero to 200Vac, usually at least 7 Vp-p. They all output AC voltage, unless there is built-in circuitry. If there is no built-in circuitry, you can convert the AC signal to DC pulses using a diode to only pass the positive phase of the AC signal followed by a resistor and 4.7V zener diode to clamp the maximum to 4.7 volts. More sensitive circuitry is possible, but also more complex. This digital pulse signal may need to feed an interrupt pin or a counter.

Doug

Thanks Doug for the reply. And yes this will go in to a car. I thought from the spec I read, the board was good up to 20vdc max. If I understand you correctly the inputs must be 5vdc max and all outputs will need to control 5vdc relays. And does the 5vdc max go for the Analog input to.

If so any analog signals (0-12vdc) will need to be reduced to 0-5vdc for the Analog Input. And I guess I will need a DAC for the output of 0-12vdc.

1 function of what need to control is my gas gauge. I replaced the tank in an old car and it does not have any baffles in it and the gas gauge bounces all around. I figured I would input the sending unit into an analog input. Write code so when I start the car it would take the current reading and output that voltage to the gauge then I would sample the sending unit every 1sec for 15sec's take the average of those readings and compare to the current output voltage and if within 95% of the current output then reset the output to the new reading then repeat. If it was not within the 95% then skip and repeat.

Once I get this working I then want to add a Miles per Gal display which will require a Flow meter & a speed sensor, which I think I will use a proxy instead of the magnetic sensor.

And the finial function would be to control the Lockup Torque Converter in the new transmission I installed. This will also require a Vacuum analog sensor and an analog Throttle Position Sensor along with the Speed Sensor.