Processor speed is a concern not for computational reasons but for timing - we need the difference in time of flight for the radio waves which travel at the speed of light so we need a fast enough clock for whatever accuracy we want. I think that once this type of system is established, it will give much more accurate and reliable readings then the other method we discussed.
The other method, which I believe you are referring to, is to simply read the signal strength (already built into Zigbee) and extrapolate from there but as we discussed the other weekend, analog signals are noisy and this one in particular has many different variables affecting it other than distance. I think that it would be a quick and easy way to get ball park estimates but would be difficult to get very precise.
What if you just had a 12v solar panel hooked up to the wench directly? That way you save the expense of a battery assuming you don't mind it not running at a constant rate.
Hey Eric,
Can't tell you how excited I am to hear about your progress! I've uploaded the [current Fido library](https://github.com/lthiery/Fido) to Github but I have a few caveats based on what your post.
If you remember [a post I made a few weeks ago](http://www.farmhack.org/forums/pushing-arduino-memory), Fido was getting strapped for memory. In response to that, I switched to an analog temperature sensor (see new BoM) instead of the DS18B20. It won't be difficult for you to change the getTemp() function such that it will work with the DS again but you'll probably run out of flash memory, especially if you also have the LCD. Thus, if you want to keep all those components, you might have to strip down some of the things from the Fido library I've uploaded; a good place to start is to play around with those char arrays in the beginning of the code. They're written in PROGMEM but I think you'll catch on quickly if you read this [post on my site](http://louisthiery.com/avr-memory-challenges/).
Anyway, let me know if you have any questions! Oh and I actually have a question for you: is that voltage divider giving you fairly reliable reads? I changed mine out for a logic shifter and it's been more consistent for me; I ordered quite a few and I'd be happy to send you one if you PM me your address (they cost 40 cents but if you go about trying to buy just one you'll end up spending 5 dollars).
Would you pair each one of these with an Arduino? If so, that seems like a hassle and you might be better off using [Xbee chips](http://www.sparkfun.com/products/10414) since they would be able to take your readings and send them without an Arduino and you would be saving some money and development time.
It might be a fun project to buy the RF transmitter/receive modules and pair them with AVR chips yourself (ie: buying the chip and not the Arduino) and you might finagle something cheaper than an Xbee chip but otherwise I'd recommend Xbee with an analog sensor.
Comments
Processor speed is a concern
What if you just had a 12v
Portable Design
Simply awesome
Response to Using a RF Transmitter/Receiver