Table of Contents
FPGA Fan Controller
My Ceiling fan is controlled by a Hunter Fan Co 27185 remote control, which transmits with OOK (On-off keying) at 350MHz.
Internally the device uses a HT12E encoder chip driving a 350MHz LC oscillator.
Capture
Gqrx
I used my RTLSDR and Gqrx to capture transmissions from the remote, which revealed the following things…
- When buttons are pressed, bunches of packets are transmitted in OOK (On-offkeying).
- The carrier frequency is not at all accurately tuned to 350MHz, and drifts significantly based on the transmitter's relative to other objects, and to temperature. This is to be expected with an LC oscillator with no accurate frequency reference.
Inspectrum
GNU Radio
iCE40 FPGA Implementation
