We’ve featured a Bluetooth-based program that automatically locks Windows PCs when the user walks away. Here’s another approach to automatically locking a computer. While the Bluetooth-based program relied on proximity, Didier Stevens’ program LockIfNotHot works in conjunction with an IR thermometer to detect changes in the surrounding temperature.
As the program’s name says it will lock the computer when the temperature in the surrounding area – basically where the sensor is pointed at – drops. You can set the temperature threshold as well as the amount of time before the PC auto locks, e.g. you can set it to lock the computer when the temperature drops to 20ºC and below, and if that drop is sustained for 5 seconds.
The sensor’s responsiveness is impressive. The advantage that the Bluetooth-based unlock program has over LockIfNotHot is that it can both lock and unlock a computer automatically. But Stevens probably realized that making his program work both ways – i.e. unlock the computer if it gets warmer – would be quite dangerous, since any object that causes an increase in temperature will trigger that function, so he just left it as it is. Once the PC is locked you’ll have to log in the normal way and enter the password.