6) What does it take to build a thermostat circuit?
I have made something similar for my house, although the needs are slightly different the concept is the same. I wanted to :-1. measure temperature of env and rooms2. measure Humidity3. Control Combination of swamp coolers and Window ACs (not central ) using humidex (derived from temperature and humidity)Did this using a combination of arduinos, nRF24L01+ transreceivers, Mango M2M software (used this for datalogging, graphical display and control). I deployed Mango on a old laptop, however, think you can very easily do that on a raspberry pi as well.if you want to take a look, the WIP posts are at http://fotohobbist.com/blog/arduino-mango-m2m-data-logging/
cool, let me know vif you need any help. I will also post on control points and how calculations on raw analog (ADC) values from the arduno can be done within mango vs arduino. it may also help to read/implement the mesh protocol for the nRf24L01+ modules. I made some modification to it to differentiate between data and command packets.have started to put together something to get you started at http://fotohobbist.com/blog/remote-data-logging-with-arduino-bringing-it-all-together/ Note : This is still WIP, but should give you some pointers
I use all DS18B20 or DHT11 sensors so will rely on their inbuilt digital temperature numbers. I have a number of the nordic modules and have also susbscribed to the kickstarter for the new Digix product that has them onboard so i will probably use on of them as my central node. I was planning on using maniac bugs nordic libraries as they seem the most comprehensive - did you start there ?