DIY Force Sensitive Resistor (FSR)





Introduction: DIY Force Sensitive Resistor (FSR)

Make a force sensitive resistor (a pressure sensor) with spare parts instead of spending $5 - $20 each.

Step 1: Materials


  • Soldering iron
  • Hot glue gun
  • Knife/razor
  • Wire cutter


  • Solder
  • Hot glue
  • One-sided copper PCB
  • Conductive foam
  • Wire

The foam

Conductive foam is what microcontrollers generally come packaged in. If you've received little ATmega microcontrollers or PICs, sometimes they'll be surrounded by conductive foam inside a little case or box. Not all conductive foam is created equal: some of it bounces back into shape faster than others. If you use PIC foam to make your FSR, it will respond quickly, but if you use ATmega foam will take a second to release. The fact that this FSR has a visible deformation is the primary difference from other FSRs.

Step 2: Sizing

Use the knife/razor to score your PCB into two plates that mirror each other. I went with approximately one-square-inch squares, but you could do any two shapes so long as there is copper in between.

Cut your foam into the same shape as the plate.

Solder one wire to each plate. You'll want to make sure the solder is going to hold the wire in place, so clean the copper beforehand if necessary and use plenty of solder.

Step 3: Connecting the Pieces

Glue the three pieces together. Only glue along the outline of the FSR, otherwise it will not conduct well. For mine, I just glued the top and bottom of both plates to the foam.

Step 4: Test It Out

Grab a multimeter and measure the resistance across your FSR. Your values will vary, but I got about 200 kiloohms at rest and 9 kiloohms when almost completely depressed. If your plates have a larger surface area, or the foam in between is thinner, these values will be smaller.

Step 5: Notes


  • Use it to Dim an LED (video + code)
  • Use it to Make some noise (video)
  • Try different kinds of foam (test resistance across the foam first to make sure it's conductive)
  • Cut unusual shapes
  • Test different foam configurations (e.g.: multi-layered foam)
  • Test different plate materials (e.g.: aluminum foil on cardboard/plastic/wood)
  • Make humongous FSR arrays


SensorWiki FSR page explains FSR theory and use, with examples
Protolab explanation of FSR use in the context of other sensors

Thanks to Dane Kouttron and Zach Barth for introducing this technique to me, and leaving a few FSRs around the eclub.



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would this concept work if the weight on the pressure plate was that of the weight of a pill or a door key? Am creating a school project and need to create an extremely sensitive pressure plate!

Hello, thank you for the tutorial, I want to know if there are any way to connect to arduino in order to get the variables changing when applying force, I need to do a surface that will be able to detect when people hands over it and then create a reaction in a liquid (non newtonian) using speakers / changing frequencies depending force applied.

can it be possible?


I am new to FSR but I think it is no different than connecting a potentiometer to arduino. If I am correct, analog read is just reading the voltage in range of 0-1023. So if you connect FSR red side to 5v, connect a resister in series with FSR and connect the resister to any analog in then it should give a read for you. of course you need to program arduino but you can figure it out yourself

hey thank you for your reply, yes Ive purchased some FSR to use in the surface, used some sample codes on internet to get some numbers from it depending force applied, the thing is how can I use this numbers to control the volume in a external power amplifier who is connected to a speaker, so depending people force over sensor the volume increase reproduced by speaker. regards!

I'm looking to be able to apply potentially hundreds of pounds to a force sensor and detect the weight applied. Would this work for this project?

I wouldn't count on it. Your better off just getting a few load sensors from alibaba or ebay for a few bucks. These aren't very accurite.

if you wanted to measure force in the hundreds of pounds could this work?

I could use some of those... Are these similar to what you would find in a keyboard? Obviously keyboards work generally via two contacts and a spacer sheet. Do you think I could use a keyboard circuit to make some of these?

As far as I know, most keyboards keys are switches. According to HowStuffWorks there used to be "foam element" keyboards, but I don't know if they were more like switches or thresholded FSRs.

I'm guessing a keyboard circuit wouldn't be very useful for making a matrix of these; but I haven't really dissected enough keyboards, so don't let me dissuade you :)