Application Examples

Multihop Counter (UnicastCountToLeds)

UnicastCountToLeds acts very similarly to the TinyOS example applicaton RadioCountToLeds, in which a 4Hz counter is maintained, and then the value is sent over the radio and displayed on LEDs of another node. However, here only node 0 sends a unicast message to node 1 with its value, rather than having each node broadcast its value in an AM packet every time it gets updated. Normally this would require nodes 0 and 1 to be within radio range of each other, but by simply using the send and receive components from the COMPASS framework, the message can be delivered across multiple hops to reach node 1 (assuming there is a path connecting node 0 and 1 in the network).

Visual Route Tracer (MultihopLight)

The intensity of light at a source mote A is used to control an LED at a destination mote B. The COMPASS multihop framework is used to allow the source and destination to be an arbitrary number of hops away from each other. By reducing radio power to a low level, this application acts as simple visual demo of the utility of multihop communication. All other nodes act as forwarders between nodes A and B, and can be added and removed at any time, causing the routing path between A and B to change in real time. The on/off setting of this LED is displayed throughout the path taken by the packets, making this system a rudimentary route tracer.