Force Sensitive Resistor Hookup Guide
Force-sensitive resistor’s (FSR) are easy-to-use sensors designed for measuring the presence and relative magnitude of localized physical pressure.
The resistance of an FSR varies as the force on the sensor increases or decreases. When no pressure is being applied to the FSR, its resistance will be larger than 1MΩ. The harder you press on the sensor’s head, the lower the resistance between the two terminals drops. By combining the FSR with a static resistor to create a voltage divider, you can produce a variable voltage that can be read by a microcontroller’s analog-to-digital converter.
This tutorial serves as a quick primer on FSR’s and demonstrates how to hook them up and use them. Beyond an FSR of your choice, the following materials are recommended:
Arduino Uno – We’ll be using the Arduino’s analog-to-digital converter to read in the variable resistance of the FSR. Any Arduino-compatible development platform – be it a RedBoard, Pro or Pro Mini – can substitute.
Resistor Kit – To turn the FSR’s variable resistance into a readable voltage, we’ll combine it with a static resistor to create a voltage divider. This resistor kit is handy for some trial-and-error testing to hone in on the most sensitive circuit possible.
Force Sensitive Resistor Adapter – While the FSR terminals are breadboard-compatible, we’ve found that it may be loose in the breadboard. For those looking for a way to make a more secure connection without soldering, try looking at the associated Amphenol pin adapters. You will need a pair of needle nose pliers to clamp the the adapter down. For a demo of how to use the Amphenol connectors, check out the SparkFun Hot Tip.
Analog components, like these FSRs, are a great sensor-reading entry-point for beginners, but there are a few electronics concepts you should be familiar with. If any of these tutorial titles sound foreign to you, consider skimming through that content first.