kasslloyd:
Yea I sent a PM.If its just an AVR per box, then it's size is irrelevent, since it can be outside of the hive, just put a connector on the outside of the box that goes in to connect to each of the frames. Then the AVR for the box can be safely mounted outside. If it's per frame, then that will need some tiny chips, which would be an issue I think. :-\
This is where my understanding of Dallas 1-wire is not so good. AFAIK the 1-wire library only reads on 1 pin but I don't see why an AVR can't keep up with a few such wires. If it's 1:1 then go with Tiny AVR's, I bought 10 years ago from Mouser for $1.30-some each.
There will need to be a way for the AVR to tell each frame apart, without any mixups, even if the order of frames change.
The DS18B20 ID of the 1st sensor in the frame is not good enough?
I would then assume the AVR's for the boxes would then connect to an Arduino that will read via a serial line the temp data out? Or, we could just actually burn the Arduino patform onto individual AVR's
Arduino boards are development boards. UNO costs about $25. UNO chip costs about $2.50. The board has the USB chip and USB jack and power regulator, clock crystals and connectors that you don't need as long as you can supply regulated power, solid ground, be happy at 8 MHz or less and not want USB.
The chip is a complete self-contained small computer. Load the code and wire it up, that's all it takes. Add what you need, in-deed.
per box, then connect all those back up to the central computer and write a simple program that reads out the temp data every 10 minutes and saves it as a CSV, that would be the ideal?
We could run several Cat5 cables from the hive back into the house, then put individual serial lines on those wires, then connect it all up via USB-to-Serial connectors inside, then a small program to read out those datas and write to a CSV... nothing complex here, just needs to be stable ;-\
You can add an SD card to each hive and swap out chips as you do the physical inspections you will be doing anyway. I get SD modules from LC Tech in China, below costs I see on eBay. If you're okay about soldering, a micro-SD to full SD adapter (the thing they usually sell with a micro-SD chip so it can fit & work in a full size slot) can be turned into a module with a few resistors for voltage dividers.. that you only need for 5V operation. If you run your AVR's at 3.3V (I think you can at 8 MHz, know you can't at 16.) then you can wire the SD adapter direct.
I think that SD would be cheaper than long cable runs and the chips you'd need to handle the extra voltage required for long cable runs. Also with cables, you need something running all the time to receive data.