Wireless Networks for Multi- Robot Communications Creating a Sensor Network of Robots.

Project Purpose Create a sensor network of robots that, together, achieve a shared goal.

What is a Sensor Network? A sensor network contains multiple devices. Each device has devices on it that can sense conditions of the outside world, or sensors. Each device communicates to other devices in order to achieve a shared goal.

Advantages of Sensor Networks Jobs can be complete with large numbers of units in parallel Redundancy: Each unit of the network can be destroyed with little to no damage to the network as a whole

Jobs of Sensor Network Surveillance: Sensor network can cover a large are, and collate the data before it reaches the user Search: Sensor networks can cover multiple parts simultaneously for quicker results. Remote Monitoring and Control

Design Problem Develop a wireless communication network for multi-robot teams. This network, preferably made with radio frequency transceivers, plus the on board sensors of the robots themselves, will form a sensor network, in order to locate a light source.

Existing Implementations DARPA has sponsored a project for “smart dust”: a sensor network of thousands all small enough to float in the wind, to be used for surveillance.

TinyOS and TinyDB Part of the DARPA project is the creation of an embedded operating system to run units on the sensor network, called TinyOS, and a data gathering utility, TinyDB

RFID Tags These tags are small devices that transmit an ID number when hit with a radio frequency.

Design Constraints The project must… Maneuver around objects. Search for target. Realize it has found target. Signal other robots. Search for robot that signals. Wait for turn to communicate. Not interfere or be interfered with in terms of RF communications.

Design Constraints The project should… Be easy to modify system behavior. Be easy to interface. Use parts and tools readily available. Sense obstacles to avoid contact. Use small enough area to ensure the RF transmitters can reach all distances.

Feasibility Study Show the project is physically, technically, and economically feasible in the time available. Similar projects have been successfully completed. Can use past projects for guidelines and ideas. Budget is within reason. Using mature technologies such as RF and photocells. Easy to interface with robots.

Survey of Products AmigoBot (ActiveMedia) Khepera (K-Team) Trilobot (Arrick Electronics) Hexapod (LynxMotion) Boebot (Parallax)

AmigoBot Comes with battery and battery charger Comes with AmigoOS and AmigoBot User Guide Great Indoor/Outdoor range Comes with various packages (e.g. Wirefree) Too Expensive

Khepera Not Enough Payload to add on RF products Shorter whiskers than Boebot Light, compact design Limited kits available

Trilobot Heaviest of all robots 8 whiskers around base 4 light level sensors Digital tempature sensor Engineered for easy expansion Once again…

Hexapod Never specified payload Lacking Documentation and manuals Affordable Price

Boebot Comes with BasicStamp2 Get Full Kit with each robot purchase Extensive Documentation and very adaptable Price is right!

Budget Product Quantity Price Boebot Full Kit (w/shipping) Transmitter (TWS-434) Receiver (RWS-434) MHz Antenna (w/shipping) Alkaline Batteries (AA) Total Cost

Design Validation Test servos, whiskers, photoresistors, and IR subsystem individually as outlined in Boe-Bot manual Integrate and test servos, whiskers, photoresistors, and IR subsystem

Search and Communicate Implement and test random search for light using single Boe-Bot Implement and test patterned search for light using single Boe-Bot Implement and test RF communication between two Boe- Bots Develop, implement, and test a communication protocol for multiple Boe-Bots

Putting it all Together Combine communication protocol with individual Boe-Bot random and pattern searches Begin stepwise refinement Determine which search is best Determine how close Boe-Bots should get to each other before moving away from each other Enhance communication protocol

ProposalChoose parts Order parts Connect servos to robots Build robots Get robots moving Connect whiskers Write and implement obstacle avoidance software Connect photocells Write and implement light sensing software Connect RF transmitter and receiver Write and implement RF software Write and implement networking protocol Connect IR Write and implement IR Write and implement object searching Write and implement object tracking Create team (Optional – if time permits) Search and rescue lost robots

Complications Test with various objects blocking the search Test with Boe-Bots being dynamically added and removed from the search