Final bits from Mouser January 5
Okay, probably not the *final* bits — but I recieved the last couple parts I was waiting on for the KAP rig. The radios I had been using (Xbee Series 2) were a little cumbersome, mainly because they required a PAN coordinator. Super cool if you were doing a mesh network of sensors or robots or other things like that, not as useful for the point-to-point network I was working on. My fault, I didn’t read the spec sheets close enough.
I had started with the series2 mainly because they had an extra 20m of range on the series1, I think I’ll live as-is. The biggest hurdle was that the firmware for the coordinator was a little different, and of course the radio that’s in need of being reflashed is the coordinator, and I don’t have the hardware setup to flash the xbee. So I’m hanging on to these radios in the expectation that I will end up creating some sort of mesh network for some random project. (Possibly a weather station on my house)
So I ordered a couple xbee series 1 radios, which showed up this morning via USPS, along with another linear regulator and a couple of dip switches. The last bits are all hooked in, configured, and working. The radios out of the box talk to each other, but it’s by using the default PAN ID and broadcasting. I wanted a more restrictive setup, so I changed the PAN ID, upped the bitrate to 115200 and set the destination address to be the other radio’s serial number. The other big thing with the xbee series 1 radios is that I can buy them from anyone. The series 2 radios just hit the market, are only now in distribution (but only with the router firmware).
A handy command when setting up the radios for this sort of “real time” application is ATRO0 — this sets the packetization threshold to 0 bytes, so it sends out packets of single bytes instead of waiting until it has a few to send.
I also found that the reciever side doesn’t see bytes while it is taking a picture. I think the bytes overflow the buffer or something during the various delay loops in the shutter() command. The workaround? Send out current mode and rotational stop commands periodically to make sure it doesn’t get stuck spinning around in circles. This also has the feature of allowing there to be a “timeout” counter that will wait some amount of time (5 seconds, currently) to switch the rig into autokap mode if there isn’t a beacon signal from the controller. This timeout is disabled when the rig is in film mode (dip switch 2 is on).