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Fast, Portable and Affordable Oscilloscope and Inductance Meter
This is super cool! You should try and use a digital shutter such as an old LCD display instead of a manual one. You'd just need to rip the back light off and send the light strait through that way you can try out tons of different shutter/ cutter styles and be able to instantly stop the cutting based on the display brightness. It might be too much shade but you never know...
Temperature Control With Arduino and PWM Fans
So through out the process the vapor escapes the food and fills the desiccant enriched jar, the second vacuuming is meant to make sure the vapor goes away and that the water in the vapor inside does not erode your seal on your jar. As for your other question, yeah I just tried two different ways of doing it.
Gel Electrophoresis Integrated System (GelIS)
DIY - Portable Mini Photo Studio
Freeze Dry At Home
Turn your Arduino into a 4 voice wavetable synth with only a few components...
Arduino Waveform Generator
Touche for Arduino: Advanced touch sensing.