A simple teeth pressure sensor, built using an FSR (Force-Sensitive Resistor)

Cost

Around 20-25€, depending mostly on which microcontroller you choose.

Building difficulty

Low-Medium. Requires:

• Some trials to build it correctly and put the sensor in the correct position
• Some light understanding on how to calibrate the sensor
• Not mandatory but recommended: soldering

Components

I’ve included links to sample components to take a look at them, but you can find them elsewhere on other shops, sometimes even at better prices.

• Arduino microcontroller (Uno, Nano, whatever. Elegoo makes cheaper compatible chips);
• USB Type A to Type B cable (to connect Arduino to your PC. Often included with Arduino);
• A 10kΩ resistor (e.g. RP-C10-ST), and a 2kg FSR (Force-Sensitive Resistor). You can easily find them on Amazon or microelectronics store online such as Mouser;
• A set of jumper wires for microelectronics (including both male-male, male-female and female-female connectors). Alternatively, if you have a soldering iron and you’re comfortable with soldering, you can use normal microelectronics wires;
• Small and flat pieces of wood. An ice cream stick will serve the purpose;
• Insulating tape.

Procedure

1. Using the jumper wires, replicate the scheme you see in the first image. Be careful to place the resistance in the same order.
   • It is better if you can solder the resistance together with the cables. Chaining these things together without a soldering iron could be tricky, however it’s feasible with some patience using insulating tape;
   • Cables A and B can be prolonged by chaining together jumper wires. Make sure to make the cable long enough to reach your mouth (e.g. using 5 pairs of jumper cables chained together);
   • The FSR will need two female jumpers;
2. Replicate the mouthpiece you can see in Fig. 2. You can cut an extremity of the ice cream stick and use it to enclose the FSR, or you can use the extremity of another ice cream stick for the same purpose.
   • Better if you hold in place the FSR using a gentle layer of insulating tape;
   • When placing the final layer of tape which encapsulates the FSR and the wooden stick, try to tighten the insulating tape as little as possible, in order to create as little pressure as possible on the sensor;
   • Create a small dimple for the teeth in the center of the FSR using insulating tape. This will help keep the teeth in the right position, ensuring consistent pressure values.