Body heat sensing PC security system

lockifnothot

[Didier Stevens] wrote in to tell us about a little piece of PC security software he put together recently. His application, LockIfNotHot, works in conjunction with your PC as well as an IR temperature sensor in order to lock your computer the moment you step away.

The theory behind the system is pretty simple. Basically, the IR temp sensor monitors when you are at your desk, sensing your presence by the heat your body gives off. As soon as you step away however, it locks the computer since the temperature of the surrounding area immediately drops. It’s pretty simple, but as you can see in the video below, it works quite well.

The software has configurable set points and timeout values, which make it flexible enough to adapt to your specific situation. He happens to use an off-the-shelf IR sensor, but we assume any USB temperature module will do the trick. If you happen to work with sensitive information but often forget to lock your workstation, this is the program for you!

Continue reading to see a quick demonstration of his software in action.

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Growing algae with an Arduino

algae_grow

We’ve seen automated grow boxes of all shapes and sizes, but all were for growing plants. [Jared] over at Inventgeek wanted to do something similar for his algae. He started off with an Arduino-based solution that allows the controlled pulse of LEDs connected to his standard bioreactor as a prototype. Once he determined his proof of concept worked, he began work on a design based on the Arduino Pro Mini that has more advanced features such as temperature monitoring and algae culture density monitoring via some fancy IR voodoo. The code is open source and the hardware is easily obtainable, all that remains is the desire to grow algae.