Design a controler for an apratment storage heater
- Status: Closed
- Prize: $50
- Entries Received: 5
- Winner: anatol33
Summary: design an electro-mechanical controller for a residential storage heater via the two control knobs on top.
I live in an apartment with 5 of these heaters (you can research them online here) [login to view URL]
per the article they have two controls, shown in the attached photos. I want a way to control these heaters from my computer/iphone so I control the charge/discharge remotely and/or automatically. The circuit that powers these heaters is only on from 10pm to 12 noon, then shuts off…If I have forgotten to charge the heaters and its cool, then I'm out of luck until 10pm…brrrr. Maybe the app can look up the weather report for tomorrow and think ahead. That is it any solution is fair game. Here are some constraints, the comments in  are my ideas you can ignore or use these as you see fit, they are provided more to give you a sense of what I THINK the challenges are you may have better ideas of what the real problems will be.
• I cannot modify the devices, or harm them in any way, this is a rental. So for example I cannot just tap into the power supply and insert a relay, they are hard wired, I cannot drill into the case or remove the handles of the knobs
o [maybe magnets could hold a frame onto the steel case, and or the case could wrap around the edges of the unit to push against the torque of turning the vent dial]
o [The knobs have lots of surface area to grip, but the grip has to be non destructive, maybe 4 pins or a molded epoxy putty with a key shaft, formed around the knob protected with saran wrap?]
• The left knob, controls a flap that controls air flow through the brick core, it is very hard to turn, maybe a kg of force on each finger, hard to do with two pinky fingers, firm but moderate with a thumb and forefinger, the right knob, the thermostat is very smooth and easy to turn
o [a stronger servo/stepper motor may be needed for the left one]
• The knobs turn about 320 deg, but I think I could get buy with 180 deg, OK, more would be better but 180 would work. The first 90 deg, starting at the * does not seem to do much.
o [most servos only go 180]
• The face plate says the unit consumes 800W and can store over 10kwH, maybe it would be cool to have a room temp and unit temp sensor, but maybe not needed?
o Top of the unit (where the knobs are) gets quite hot but you can just barely hold your hand on it, so mechanism should be ok, and a therm couple there could estimate internal temp, if that is useful.
My goal is to build (all or mostly by myself) several of these units, so I'm looking for a design which:
• Is easy to make with only basic tools that balances total cost with ease. For example it would be cool to have the mounting frame 3D printed so I would not have to construct it, but that is expensive. I would like to keep the cost below $100/unit. Lower would be great
o So if you think the 3D printing thing is the way to go, maybe you can sketch the design in some 3d software?
• I have basic electronics and programming skills, I can handle the logic for the program but am open to suggestions, schematics etc. I was thinking an arduino or rasberry pi?
• Speed is not important
• Looks are not important
• Does not need to be easy on/easy off and does not need to be manually settible, I'm ok if all setting need to take place through app/phone.
• We have wifi.
I am open to any solution that accomplishes the goal of allowing automation. The winning solution will get me to a functioning prototype as fast and cheaply as possible. I thought about a robot but…
My reference solution ( that you have to beat to be in the running) is a plastic box, held on by magnets with two survoes, controlled by an arduino, with wifi connected to some kind of home automation cloud based solution.
“good design for me”
ljsweeny, United States.