In this project I created an infrared (IR) link that provides bi-directional communication between the NXT and the new Power-Functions system, which consists of a battery box, motors, a remote control (an IR transmitter) and an IR receiver that controls the motors.
I previously built an IR transmitter for the NXT which used an MSP430 microcontroller and which was able to send Sony IR commands (the specifications of this protocol are widely available).
Build Accurate LC Meter and start making your own coils and inductors. This LC Meter allows to measure incredibly small inductances making it perfect tool for making all types of RF coils. LC Meter can measure inductances starting from 10nH - 1000nH, 1uH - 1000uH, 1mH - 100mH and capacitances from 0.1pF up to 900nF. The circuit includes an auto ranging and reset function to make sure the readings are as accurate as possible ... [more]