It appears that some of the new paddle designs have abandoned the time tested coin silver contacts and are using "improved" alloys in an attempt to avoid problems with oxidation. While those alloys and/or surface treatments seem to be reliable when used in circuits with a high threshold separating "key up" and "key down" states, the new contacts are a problem with PIC based keyers like WinKey that use a voltage divider and single input pin to sense both the "dit" and "dah" paddle closure.
These new alloys appear to create a semiconductor contact rather than a purely conductive one. In trying to discover and fix the problems with a few of the newer paddle designs and WinKey, it appears that the voltage drop across the paddle contacts is essentially independent of the current through the contacts. In one test, the divider resistors in the WinKey input network were scaled by a factor of 10 in an attempt to make contact resistance a smaller part of overall circuit resistance ... with absolutely no difference in behavior! This surprising response is exactly what would be predicted if the contacts were acting like a forward biased diode.
To accommodate these new paddle designs, K1EL and microHAM have cooperated to produce a "paddle processor/debouncer." The debouncer uses a micropower PIC with independent, high threshold inputs to sense the paddle state. Paddle closures are processed with an advanced debouncing algorithm to remove all "noise" on the inputs and passed on to the keyer as unambiguous levels.
The debouncer consumes less than 1 mA in operation and about 1 uA in sleep mode. It will operate for several years on the internal "coin" battery without the need for a power switch.
The debouncer is available in two versions. Both versions have 20 cm output cables terminated in a standard 1/4" stereo plug to connector to microKEYER or CW Keyer. The Begali version has a one meter long input cable which terminates in a 3.5 mm (1/8") stereo plug which will connect directly to the paddles. The generic version replaces the 3.5 mm plug with a 1/4" stereo jack.
