WA5ZNU 13cm Synthesizer Project

Calling this a "project" is a bit of an overstatement; it's a collection of parts I happened in to for about $10. Today at the Silicon Valley Electronics Flea Market.


I got a Si Labs 4136bt-evb evaluation board. It's frequency synthesizer with a switchable 2.2 GHz / 2.4 GHz and a separate 100-500 MHz IF synthesized output.

(data, EVB data)



I also picked up a hex-key pad which has the classic 74C922N / CD4021B matrix decoder and shift register combo, which is even described for the Arduino in ShiftIn. Xilex turns out to have beena low-volum custom manufacturer of FM car phones in the early 1980's. I found a page by WB6NVH describing them, and it has the keypad right there. I traced out the pins, only to find that the header has them nicely labeled already: GND + C L D.

Xilex hex pad back Xilex hex pad


I thought it was a VFD display, but it's transreflective and LED illuminated and an Optrex C-51846 parallel interface with the NT3881D driver. This is perhaps not the best score today.

(C51847 data, driver data, discussion, Adafruit Adruino Tutorial)

Or, this SparkFun Serial LCD Backpack looks like a sturdy interface at $17.

Optrex C-51846 LCD Back Optrex C-51846 LCD