The project is a house thermostat and blower controller. But first a little background so you can understand what the thermostat/controller does. We live in a solar heated house in New Jersey. The airhandler pulls the solar heated warm air from the second floor of the house and distributes it thru ducts in the one foot think concrete slab in the basement. The slab and house are fully insulated on the outside of the building using R35 rigid insulation. The slab is our heat storage. During the night the warmed slab gives off heat energy back into the house via the air ducts and blower. The slab is referred to as the Heat Energy Battery or HEB.
The engineer that designed the house specified that the airhandler blower would be left on full speed 24/7. We've lived in this house since we built it in 1995. Living here I realized that the blower does not need to go full speed all the time. The blower speed can be slowed down to save energy that the the blower motor uses. To calculate the blower speed I use temperature sensors in the HEB, top of airshaft (where the warm air is at the top of the vaulted ceilings), and outside temp. There are also temp sensors for the inside (ambient temp) and solar hot water coil in the air handler.
The speed is calculated and is sent via 4 bits (4 pins on the Teensy) to the Variable Frequency motor drive. The drive can handle up to 4 bits if data for a total of 16 speeds.
You can read more on our website
A quick update. Everything is working fine on the Teensy. What a great product! I have difficulty soldering the smaller surface mount components and a module like the Teensy really works well for me. Along with the integration into Arduino and it makes many development headaches go away. Libraries that I use and work fine on the Teensy:
- Ethernet - Server and Udp
- One Wire