Hello
I just found jeenodes, and this is exactly what I was looking for. I bought a jeelink + an usb jeenode and made them work in a few minutes. Excellent!
Now my project is to extend my existing 1wire based HVAC control system with wireless sensors and some domotic controls. The existing system is fully based with a python program and a 1 wire network.
Some jeenodes would be battery powered. What I need, is that the nodes could monitor the batteries themself, and send a warning for replacement or recharge. I found this big (2300mAh) cheap li/ion battery http://www.dealextreme.com/details.dx/sku.30996 I would like to recharge the battery every 3-6months... Looking at the schematic, it looks like everything is here to do this: the max1555, the adc connection, very cool!
Now I need a safe and power saving protocol between the nodes. For an alarm, rf jammers should be detected. So the main node(s) should be monitoring the presence of all sensors. The model I have in mind the that the sensors would regularly send a presence packet every 30s to the main node(s).
Every packet should be acknowledged, and a retry algorithm (with a random delay to avoid deadlock colision). a packet checksum would be a nice feature. The Ack packets would contain the received computed checksum. The transmiter would retry if the ack checksum is wrong.
Has anyone made such a safe communication protocol? (retries, packet checking, collision avoidance, etc...)
Should tdma be implemented? or collision avoidance would be enough? I think the second solution is simpler.
Is there any public project doing this?
Thanks for this very nice work!