Well, I had a day of downtime this past week and finally got all of my toys out to play with. For those unfamiliar, an Arduino is a small programmable logic board that can interface with almost anything. I paired one with a temperature probe and a relay block -- the probe is tethered to one of the knob mounts on the stove's top plate, while the relay block is running to where the toggle switch used to be.
When I had the fireplace out last, I pulled out the old disintegrated thermal switches and instead ran it so the toggle switch up put the fan on full blast and down was low. With the relays, I now get exact control.
This is able to do so much more than what the original 3 thermal switches could do. Since the probe maxes out at 100C, I had to place it off center so it wouldn't burn out, but that means the readings are slightly delayed as the temperature changes work their way out. To counter this, I calculate a moving average and compare the current temperature against that. There's threshold counts for rising and falling temps (so the fan doesn't bounce back and forth).
So far, it's been remarkably accurate -- when the fan switches to low after a long burn, it's almost the perfect time to add more wood since it's not looking at a temperature, but the change in temp (when the fire starts to die down, the temp starts dropping, even if the stove is still really hot).
I'm already coming up with ways to reuse this when (fingers crossed) I upgrade to an Ideal Steel this year or next with a squirrel cage and a contactless infrared thermometer. I just ordered up some wireless transmitter/receivers so I can have it buzz me in bed when it's time to go feed the fire.
Would anyone find this code and schematic useful for their own purposes? It would definitely take some tweaking of the constants to 'fit' a different fireplace (placement of the thermal probe would dictate a lot of the on/off temps and timings).
In case it sounds like I'm way more excited about this than I should be, it's okay -- my wife already told me that. I'm more excited that this is (hopefully) letting me squeeze more life out of a smoke dragon by letting me run it in the most efficient way possible. Nothing makes me happier than going outside to get more wood and seeing nothing but heat waves coming out of the chimney.
When I had the fireplace out last, I pulled out the old disintegrated thermal switches and instead ran it so the toggle switch up put the fan on full blast and down was low. With the relays, I now get exact control.
This is able to do so much more than what the original 3 thermal switches could do. Since the probe maxes out at 100C, I had to place it off center so it wouldn't burn out, but that means the readings are slightly delayed as the temperature changes work their way out. To counter this, I calculate a moving average and compare the current temperature against that. There's threshold counts for rising and falling temps (so the fan doesn't bounce back and forth).
So far, it's been remarkably accurate -- when the fan switches to low after a long burn, it's almost the perfect time to add more wood since it's not looking at a temperature, but the change in temp (when the fire starts to die down, the temp starts dropping, even if the stove is still really hot).
I'm already coming up with ways to reuse this when (fingers crossed) I upgrade to an Ideal Steel this year or next with a squirrel cage and a contactless infrared thermometer. I just ordered up some wireless transmitter/receivers so I can have it buzz me in bed when it's time to go feed the fire.
Would anyone find this code and schematic useful for their own purposes? It would definitely take some tweaking of the constants to 'fit' a different fireplace (placement of the thermal probe would dictate a lot of the on/off temps and timings).
In case it sounds like I'm way more excited about this than I should be, it's okay -- my wife already told me that. I'm more excited that this is (hopefully) letting me squeeze more life out of a smoke dragon by letting me run it in the most efficient way possible. Nothing makes me happier than going outside to get more wood and seeing nothing but heat waves coming out of the chimney.
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Also, fun to drink of bottle of wine with the wife in front of the fire before posting here...
