B25 Voltage Sensor Module


C-3, R-5 , I-2


Product ID: 2721 SKU: SEN-2721 Categories: , Tags: ,

The Arduino analog input is limited to a 5 VDC input.   If you wish to measure higher voltages,  you will need to resort to another means.  One way is to use a voltage divider.

It is fundamentally a 5:1 voltage divider using a 30K and a 7.5K Ohm resistor.

Keep in mind, you are restricted to voltages that are less than 25 volts.   More than that and you will exceed the voltage limit of your Arduino input.



  • GND –  This is where you connect the low side of the voltage you are measuring.   Caution! : This is the same electrical point as your Arduino ground.
  • VCC:  The is where you connect the high side of  the voltage you are measuring


  • S:  This connects to your Arduino analog input.
  • – (or minus):  This connects to your Arduino ground.
  • +:  This is not connected.  It does absolutely nothing… zilch… nada… jack diddly doo doo.


The schematic for this is pretty straight forward.  As previously mentioned, its just a couple of resistors.   In fact, you could build your own in a pinch.



The Connections

Find yourself a 9 volt battery and connect it,  your voltage sensor module and Arduino as shown below.


The Sketch

Enter the following sketch, upload it and go to town.   If you open your Arduino serial monitor you will be able to see the voltage.



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