DIY Pressure Sensor

Now that you know how to add switches to your circuit, you can use a pressure sensor to control the brightness of the LED. Instead of only having the LED on or off, the LED can have varying brightness depending on how much pressure you put on the switch.

To make a pressure sensor, you will need resistive plastic, a material that changes resistance with pressure.

circuit with switch
Start by making a circuit with a switch. Note that the switch is connected to one side of the circuit.

cutting pressure sensor paper
Then, cut out a piece of resistive plastic. This material act as a resistor, so when it is placed between the circuit and the switch, current can not flow through it as well. Thus, the LED does not light up as brightly.

inserting pressure sensor paper
To power the LED, add a battery to your circuit and place the resistive plastic between the switch and the disconnected end of the circuit.

turning on LED with pressure sensor paper
Then, press down on the switch, which is now pressure sensor. When you press down on the pressure sensor, you decrease the resistance of the pressure sensor. When the resistance decreases, more current can flow through the circuit and the brightness of the LED increases. Thus, the more pressure you exert on the switch, the brighter the LED, creating a gradient of brightness rather than simply turning the light on or off.