The Pax Instruments T400 takes the form of an open source four channel thermocouple temperature datalogger, that is based on the Arduino Leonardo ... sleep mode. The RTC wakes up the unit to ...

[Alan] is branching out beyond the Arduino with this ... sensor to actuate the LCD backlight. The closer your hand is the brighter the light. The Maxim DS3232 RTC chip keeps time in this application.

I had a few problems with the PWM part mainly because the fan made a disturbing noise so I had to add a simple RC filter at the output of the PWM pin on the Arduino board. I used an LCD shield to ...