1. Rolf Therkildsen - 20021 Inter-cellular Communication Wireless Communication between self-reconfigurable robots Hydra Consortium Meeting Edinburgh – August 2002

2. Rolf Therkildsen - 20022 Progress since Zürich I have designed three robots Each robot carries two communication systems Infrared and radio The robots can find and follow each other with infrared

3. Rolf Therkildsen - 20023 Infrared - Seek and follow

4. Rolf Therkildsen - 20024 Infrared - How? Infrared modulated light 8 transceivers - covers 45 degrees each Range of up to 1 - 3 m dependent of angle The robot can not get information about distance

5. Rolf Therkildsen - 20025 Radio – Group motion

6. Rolf Therkildsen - 20026 Radio – How? 2.4 GHz module from RFWaves Range: Test shows up to 2-3 m. Supposed to cover the entire test area but…

7. Rolf Therkildsen - 20027 Radio - Problems Test in my office: Transmitted 1000 bytes, in 5 tests Same experiment, but moved 30 cm in the room.

8. Rolf Therkildsen - 20028 Radio – Problems #2 The communication is unreliable (expected) There are places where it is impossible to communicate (unexpected and annoying) The reliability are generally decreasing with range (expected)

9. Rolf Therkildsen - 20029 Compared to Bluetooth Fast connection time (The Bluetooth module has sometimes over 5 seconds) The reliability is amazingly worse (The Bluetooth module has no errors with robots up to 8 m apart) The Bluetooth module has some of the communication protocol included - this module has not

10. Rolf Therkildsen - 200210 Conclusions That infrared can be used as short range communication where positional information can be extracted and used to generate group behaviours. Due to the fact that the Israeli module is so unreliable, I recommend the Bluetooth module instead.