The Pololu IR beacon is a compact board that is used in pairs to allow robots to locate each other.
This kit contains a 125 KHz RFID reader and additional parts.
If you're going to use a RF module that needs an SMA antenna, we've got you covered! Here's a 152mm swivel/tilt whip with RP-SMA connector!
The XBee Explorer Regulated takes care of the 3.3V regulation, signal conditioning, and basic activity indicators (Power, RSSI and DIN/DOUT activity LEDs). This makes it SO much easier to start playing with XBee!
The SN171 Synapse ProtoBoard is a very convenient way to connect any Synapse SNAP module to a RS232 port - ideal for playing with your new RF Engine!