Arduino Interface -5v to 5v

Hello Everyone,

I have a question related to Arduino, I would like to read -5v to 5v input using Arduino ? How can I do that and which board you recommend for this? Please let me know your view about it, Thank you

One method: use a voltagedivider to reduce the signal to +/-2.5V, run it thru a capacitor, connect that to the junction of two 100K resistors connected to +5 and Gnd, so the signal is sitting at an offset of 2.5V, and read that with a 5V powered Ardiuno.

Capacitor value, 1uF, 10uF, 100uF, really depends on what frequency of AC you want to let thru.

Plus Minus 5V to 2.5V.jpg

Just two 10K resistors. One as pull-up from the analog input to +5V. The other in series from analog input to your -5V to +5V signal. Grounds need to be connected.

Thanks for the reply CrossRoads and dlloyd,

This is my first time in the forum. I hope you can be bit patience about my novice knowledge on electronics ;).

  1. I have a distance sensor which can measure 80mm to 300 mm.
  2. I check the voltage across the sensor at 80mm to 300 mm -22.34v to 22.34v.
  3. So, I scaled down the voltage -5v to 5v to compatible with Arduino Uno.
  4. Actually I want it to vary between (0v - 5v), (80 - 300mm). I don't want it to be a negative voltage which may possibly damage the board. How can do that?

So, Please guys let me know your view about it. Thank you :)

Welcome to the forum.

The suggestion I made should work. The series 10K resistor not only completes a voltage divider, it will protect the input from overvoltage. The sensor's output could vary from -10V to +15V without harming the Arduino's input.

Do you have a link to the sensor?

Thanks for reply dlloyd,

Please see the attached datasheet about Laser distance sensor. Let me know what you think about it.

193924_eng-Datasheet.pdf (347 KB)

Here is the manual.

The analog output is 4-20mA. Normally a 250Ω resistor is used to get 1 to 5V measured across the resistor, but at this point, I’m not sure how this would connect to an Arduino because I don’t know if analog- can be connected to Arduino GND.

What resistor did you use to get -5V to +5V? Where did you measure this from?

I guess if you just connect the grounds together, and you use something around 620Ω across analog+ and analog- you would get about 10V swing (-5V to +5V) … but the max resistance allowed in the specifications is <=500Ω.

I suggest contacting a technical representative to find out how to properly interface the analog output of this sensor to a 5V micro-controller.