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Daox · 10-13-11, 09:21 AM

Woo, cool project! Congrats on being an arduino owner. They're SUCH nifty devices.

It does sound like your thermostat is a bit limited compared to the ones I've seen. The ones I've seen/used are either a 5-2, 5-1-1, or 7 day thermostats. With the 5-2 you have one program for the weekdays and one for the weekend. The 5-1-1 gives you a program for the weekdays, one for Saturday and one for Sunday. The 7 day gives you a different program for every day of the week (and usually includes some way to copy to make programming easier/faster). Each program has four time points which can be adjusted in 15 minute incriments. At these points you select what temperature you want the house to be and thats what it aims for. That is the basics of it. If you wish to override the programming you can easily just push the up/down arrow buttons to adjust the temperature. It'll stay at that temperature until the next time point. If you wish to hold that temperature indefinitely you push a 'hold' button and it keeps that temperature until you push the hold button again. Some thermostats will allow you to adjust how much sway in temperature it'll allow. Most are set I believe to 1F. So, if you have a room set to 70F, the furnace/boiler will kick on at 69F and increase the temperature to 71F. You can adjust it to increase this temperature sway to reduce short cycling of the furnace/boiler.

I think the outside sensor is more so for heat pump applications and/or hydronic floors that have a high thermal mass. Both of these heating systems take time to get heat into the house and if there is a sudden drop in outside temperature the thermostat can kick the heating system on before the house temperature actually starts to drop.

A photoresistor would be a cheap and easy way to see if the sun is shining on the house. You could allow another degree or two drop if there is a strong sun and you know it'll start heating up the house without the furnace perhaps. I know that would work nice for something like my attic heat fan.

I'll definitely have to think more about this though. Its a very cool project.

10-13-11, 09:21 AM	#2
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	Woo, cool project! Congrats on being an arduino owner. They're SUCH nifty devices. It does sound like your thermostat is a bit limited compared to the ones I've seen. The ones I've seen/used are either a 5-2, 5-1-1, or 7 day thermostats. With the 5-2 you have one program for the weekdays and one for the weekend. The 5-1-1 gives you a program for the weekdays, one for Saturday and one for Sunday. The 7 day gives you a different program for every day of the week (and usually includes some way to copy to make programming easier/faster). Each program has four time points which can be adjusted in 15 minute incriments. At these points you select what temperature you want the house to be and thats what it aims for. That is the basics of it. If you wish to override the programming you can easily just push the up/down arrow buttons to adjust the temperature. It'll stay at that temperature until the next time point. If you wish to hold that temperature indefinitely you push a 'hold' button and it keeps that temperature until you push the hold button again. Some thermostats will allow you to adjust how much sway in temperature it'll allow. Most are set I believe to 1F. So, if you have a room set to 70F, the furnace/boiler will kick on at 69F and increase the temperature to 71F. You can adjust it to increase this temperature sway to reduce short cycling of the furnace/boiler. I think the outside sensor is more so for heat pump applications and/or hydronic floors that have a high thermal mass. Both of these heating systems take time to get heat into the house and if there is a sudden drop in outside temperature the thermostat can kick the heating system on before the house temperature actually starts to drop. A photoresistor would be a cheap and easy way to see if the sun is shining on the house. You could allow another degree or two drop if there is a strong sun and you know it'll start heating up the house without the furnace perhaps. I know that would work nice for something like my attic heat fan. I'll definitely have to think more about this though. Its a very cool project. __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.