IR Link Between Power-Function System and NXT

This IR link project was designed to create a bi-directional communication between the NXT and the Power-Functions system.

The components used in the design include an IR receiver that controls the motors, an IR transmitter remote control, motors, and a battery box. A USB programmer or debugger AVR Dragon is used to program the ATmega88 microcontroller. It uses several different protocols for programming the AVR as well as conducting in-system debugging of an AVR. This AVR Dragon should be handled with care since it is a very sensitive device.

The internal oscillator of the AVR was used in the first prototype in order to obtain a more stable oscillator for making a more robust infrared communication and to enable high-speed serial communication with the PC. An infrared LED was added to the circuit for transmitting commands to the receiver. A 940nm wavelength is emitted by this LED while sustaining up to 100mA current. A transistor can be used to drive the LED at more than 40mA. By configuring the timer to emit or not to emit its signal, the signal will be delivered to the LED when the infrared protocol requires.

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