Reddit mentions of IDUINO 2 Pcs Arduino Compatible Hall Effect Magnetic Sensor DC 5V

Making a simulated mouse trigger is very easy, get an arduino Leonardo which can be trivially programmed to emulate a USB mouse with a couple lines of code.

I am not sure what kind of IR trigger you want to implement - do you already have an IR transmitter he can trigger somehow? If that’s the case you can add an IR receiver which can receive standard IR signals from things like remote controls.

Do you need to sense something like muscular movement in his face? You might be able to hook up something like attach a small magnet with tape to his eyebrow and then position a [https://www.amazon.com/IDUINO-Arduino-Compatible-Effect-Magnetic/dp/B019GU8UY2](Hall effect sensor) nearby so he can flex an eyebrow to change the hall effect sensor reading. The hall sensor will be connected to an analog input on the arduino.

The code will look something like this:

int magnetThreshold = 300; // this value will need to be determined experimentally

void setup(){
//initiate the Mouse library
Mouse.begin();
}

void loop(){
//if the magnetic sensor is triggered send a Left mouse click
if (analogRead(1)) > magnetThreshold){
Mouse.click();
delay(1000); // wait a full second
// make sure magnet is no longer triggered
while (analogRead(1)) > magnetThreshold) {
delay(250);
}
}

There are also other kind of sensors you can use like color sensors, pressure sensors (blowing into a tube) and even tongue switches.