What is an arduino? It’s a popular, small, flexible micro-controller with a good software library that will allow me to “easily” write a program to interact with sensors and relays to ultimately build my own multi-zone, 7 day programmable thermostat with a small LCD screen that can be mounted on the wall like a conventional thermostat.

Requirements:

1. Control 2 heat sources.
2. Allow manual and programmed temperature control with override ability for the fireplace.
3. Nice, easy to read LCD containing the following:

1. Current tempurature
2. Set tempurature
3. Whether the temp is rising or falling
4. Which heating elements are selected
5. MAYBE: Number of kWh for the current month (limited by available memory storage)
6. MAYBE: Show rate of change and graph of temperature over the short term

I’ve been receiving the parts one or two at a time for a while (mostly from hong-kong) and started playing around with it last Friday (July15).

Components needed:

1. An arduino ATMEGA1280 micro-controller
2. 5 channel relay (5 individually controlled relays for AC or DC)
3. Temperature sensor
4. Photo sensor (for dimming the LCD when the room is dark (eg movie mode).
5. IR receiver (for control with my harmony universal remote)
6. RTC (real-time clock and RAM) for keeping the time during a power failure and to store the heating schedule
7. LCD display

I’ll also need some way to power it and a method to enclose and mount it nicely on the wall… which I haven’t quite decided on yet.

So far I’ve hooked up the arduino with the LCD and IR sensor on the breadboard to begin writing the software. Basically right now I’m just writing a framework to wrap my head around how all my user interactions and temp. calculations will function. I can probably get 90% of the code done within the next couple days and then I’ll be all set for when the remaining components arrive (temperature sensor and RTC).

I’m happy to report there hasn’t been any really difficult hurtles yet, and the UI is starting to look pretty good. Cheryl helped me tonight too with a few aesthetic ideas for the main screen which made it look MUCH better (but it’s not shown in the pics below, more on that later).

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