hr25_thermostat
This is an old revision of the document!
Table of Contents
Modification of Honeywell HR25 thermostat
to do
Needed Parts
You need a Honeywell Rondostat HR25 thermostat. It costs about 30,-EUR, but used items away for sometimes as low as 15,-EUR at ebay/amazon .
Partlist (in buildup order)
Amount | Part | Picture |
---|---|---|
1 | Honeywell HR20/HR25 thermostat | parts |
1 | Connector ISP 2×3 pin | |
1 | Transceiver PCB RFM12B | |
1 | Antenna (82,2mm wire) |
some thin short flexible wires to connect ISP and RFM12B with the PCB of the HR25 thermostat.
Integrate it into a housing
The RFM12B fits well inside the thermostat housing between display and PCB. If a 2×3 PCB-pin connector is used for ISP, it is possible to hide it behind the turn wheel. This way it it easy accessible for reprogramming and there is no need to modify the housing or PCB1).
Wiring of ISP and RFM12B
to do
Flashing the firmware
to do
Links
Other resources dealing with hacking of HR20/HR25 thermostats:
1)
An other option would be to sacrifice the JTAG connector, cutting and wiring some connections.
hr25_thermostat.1383566985.txt.gz · Last modified: 2013/11/04 13:09 by GoHoHa