Infra-Red Lamp

The purpose of this device is to locate objects in front of a robot using the reflected light. Why build an IR lamp when the RCX infra-red transmitter comes "free" (for an example of this method, go to Simen Svale Skogsrud's page). Two reasons: the RCX is bigger and can not always be placed in front of the model, and you can control this lamp on and off like a motor.

I used four LD271 IR LEDs mounted in a hollowed 4x2 brick. A small 2mm red LED is used as a pilot lamp. A standard diode protects the LEDs from beeing used in reverse polarity. The schematics is very simple :

I solved the problem of the LEGO connexion by splitting a LEGO cable in halves and crimped a female Molex Microfit 2 points connector. All the devices I build receive two twisted wires with fitting male connectors. These connectors are small enough, rugged and locked. (Hey Molex - want to become my sponsor ?).