Mounted one of my Xbee Control Widgets in my Yellow Critter. Worked out really well. It controls a Turnigy 20A ESC hooked to a 2300mah 4.8v nimh. Doesn’t go real fast but hey, they aren’t supposed to anyhow right? One of the output channels drives a mosfet that controls a small relay to switch the direction since the ESC is for a quad copter. It will crawl right along tho. I have some other pics and a short video on my site if anyone is interested:
Speed looks just about perfect. Nice work.
Martin’s Video
Thanks! I had heard cheap airplane ESCs wouldn’t work for trains, not sure where I read that but this one works great. $10 from Hobby King. Now if I can just squeeze two little micro servos in for the couplers, hmm…
Very cool Martin.
After looking at your pics, what handheld are you using to talk to the xbee? Something you developed?
CJ
Hey Cliff. Yeah, its a little system I developed. It’s all based on the Xbee Series 1. These are great little radio modems, they have a range of 300ft. The biggest thing though is that they are not just a point to point thing like other radios, they are based on a network protocol that is similar to wifi but at a lower level. There is no TCP/IP traffic or anything like that. 802.15.4 is the spec. It’s all point to multi-point, any node can talk to any other node. You can have up to 65536 nodes (16 bit address).
My implementation uses Atmel Attiny 1634 microcontrollers as the brain of the device. So the micro is generating the servo timing, I just pass 4 16 bit values between 0-1000 via xbee data packets and the micro clocks out the servo timings. I also pass some discrete values which I use to flip the power relay to reverse the critter.
It’s all open source, I have the software and the hardware designs published on a site called http://controlwidgets.com
The handheld is detailed on this page if you want to take a look- Handheld design
I got side tracked playing with my CNC machine (man it’s a fun toy) but I hope to get back to the control stuff soon.
Wow, very impressive!