As of today, March 13th 2012, the "Frequency Reader" supports a tuning knob which lets you retune the radio remotely. The firmware has been tailored for users of microwave transverters, but nothing prevents using it for the usual V/U/HF operations. Three buttons do:
- USB/CW mode toggle (no action if in a different mode)
- VFO A/B toggle
- tuning step selection
For interested builders, it should be noted that this new firmware works on a slightly different hardware circuit, on which few connections have been moved around to facilitate the design of PCB.
If a simple Frequency Reader is needed, just omit mounting the knob and step button leaving their terminals open.
Technical insight.
The Frequency Reader polls the radio every second for a frequency change, in case the operator touches the front panel dial knob. If the external knob is rotated, the VFO frequency is updated of a "step" amount every 100 ms. If the knob is rotated very fast, the step is increased accordingly in a linear fashion, allowing faster QSY's.
The knob component, a quadrature rotary encoder, must be selected with care. It should have no detents, or generate one step per detent. If it includes a pushbutton, it can be wired to any of the three required buttons mentioned above.
What is left to do.
- Shoot a short demo video
- Update the website with the new diagram and firmware
- Refine the firmware for general public release
