Re: uBITX Wireup Diagrams on the HF SIGNALS WEBSITE ARE WRONG!! #ubitx #ubitx-help

Jerry Gaffke

What you are missing are some resistors plus these comments from the Raduino source code file  ubitx_keyer.ino:

* CW Keyer
 * The CW keyer handles either a straight key or an iambic / paddle key.
 * They all use just one analog input line. This is how it works.
 * The analog line has the internal pull-up resistor enabled.
 * When a straight key is connected, it shorts the pull-up resistor, analog input is 0 volts
 * When a paddle is connected, the dot and the dash are connected to the analog pin through
 * a 10K and a 2.2K resistors. These produce a 4v and a 2v input to the analog pins.
 * So, the readings are as follows :
 * 0v - straight key
 * 1-2.5 v - paddle dot
 * 2.5 to 4.5 v - paddle dash
 * 2.0 to 0.5 v - dot and dash pressed
 * The keyer is written to transparently handle all these cases

So there is one wire into the Raduino, but the voltage on that single wire
says if you have nothing going on, the straight key is pressed, or the dot or dash paddles are pressed.
Very clever.

Unfortunately, it doesn't work very well.  A little bit of dirt in your straight key contacts and the
resistance there can be enough that the Raduino things it's a dot paddle press.

Here's a hardware fix, your key tells a fet to turn on, which in turn switches the resistor network:
Some of the newer firmware releases have ways around this problem also.  

Jerry, KE7ER

On Thu, May 17, 2018 at 06:02 pm, Alan Shapiro wrote:
How can the plugged in paddle work when only the tip (or ring) and ground of course,are connected?  Don't both tip and ring have to be wired?  What am I missing?

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