These are two brackets that can mount to the bottom of the Trekker to hold photo reflectors. Black and white contrast disks are included that can be read by sensors to allow the microcontroller calculate how far the robot has traveled.
This is a High current driver that will take TTL signals from your Arduino, etc to drive the relays. It includes status LEDs for each input. 5V, 12V, and 24V relay options are available. This item replaces TE-010-405 and TE-010-412
The weather resistant HRXL-MaxSonar-WR is a rugged ultrasonic sensor component module. This outdoor IP67 sensor provides very short to long distance detection and ranging in a compact, robust PVC housing.