Dear Hua, On Thu, 10 Sep 2009 23:13:30 -0400 Hua vvang <[email protected]> wrote:
> Dear all: > I am a grad student in US, I have had lots of fun with e-pucks, but recently > as I am working on the communication part, I chose to start from the ircom, > since it is a good basis to work on. Meanwhile, I found lots of confusions, > here are part of my doubts: > > 1. Is there any documentation for this ircom module? there is no extended documentation, but all the basics are explained on www.e-puck.org and the same information is put in the readme.txt of the libIrcom package. If you want to dive into the code, we can try to help you here. > 2. In term of communication, what's the relationship between sampling window > size and the packet size? (3 times? in the synchronization example the > sampling window is 32, while the packet size is 12), anyone give any tips > on it is appreciated? No there is simply no relationship. Each time a bit is transferred, robots transmit oscillating signals at some frequency (freq1 means bit 0, freq2 means bit 1). To decode efficiently the signal sent, a receiving robot samples 32 times the signal for a single bit. According to our tests, 32 is a very good choice, just do not change that, unless you want to be slower, or risk errors in communication. in the examples, packet size is 8 bits + 2 bits of synchronization + 2 bits of CRC. Practically you get only 8 bits of data. What is really going on inside the robot, is that the emitter will transmit (8 + 2 + 2) bits and the receiver will sample the signal (8+2+2) * 32 times to decode it. So, if you want to transmit 16 bits instead of 8, go into ircom.h and change ircom_wordsize to 16, for instance. But you can choose any value you like. I hope this helps you understand a bit better what's going on there, regards, alexandre campo. > > Thanks. > _______________________________________________ E-puck-dev mailing list [email protected] https://mail.gna.org/listinfo/e-puck-dev
