This is the Keyboard Keyer published in the June 1992 QST by Ed Oscarson, WA1TWX. It has some great features and its operation has been flawless. I've never noticed it generating any RF noise. As you can see from the photo, it has a low parts count and is an easy to build project. I remember building a keyboard keyer that used discrete ICs. It must have had 25 or 30 chips and I never did get it working quite right. It didn't have any memories but it did have a type ahead buffer.

My "new" keyboard keyer uses a MC68HC705 microcontroller. The version I have uses a standard AT style PC keyboard. I could have ordered another version that uses one of the old Texas Instruments surplus keyboards. With the TI keyboard, power consumption is very low. Some PC keyboards draw lots of current (200mA or more) but by running a few tests I found one that drew only 6mA. Below are my test results comparing several randomly chosen keyboards. The one I originally used was the biggest current hog.
 
 
 
 

Here are some of the features of my keyboard keyer:
* Sends standard prosigns (as well as some that I have never used)
* 255 Character buffer ( I've only overflowed the buffer by setting the speed for 5wpm and typing at 45wpm).
* 7- 256 byte messages stored in non-volatile memory.
* Keying by either FET (positive key line) or Optically coupled (negative keyline)
* 4 digit contact counter.
* Programable beacon mode.
* International Morse Code or Ameircan Morse code selection.
* CW speed from 5-99wpm.
* Set letter/word spacing.
* Sidetone enble/disable via keyboard.
* May be used with paddles.
Plus many other nice touches.

Morse Keyboards may not be your cup of tea but
I've had lots of fun with mine. I built the keyer
presented in the July 1992 QST by Ed Oscarson, WA1TWX.

The keyer draws approx. 6 mA at idle without the
AT type keyboard attached. (It can be used with paddles too.)
I never bothered to check the current drawn by the
keyboard until the keyer power was accidently left on,
discharging my 12 gelcell faster than expected.

It turns out that the keyboard I had chosen for my keyer
was a current hog. I tested several keyboards and found
that some are much better suited for battery operation
than others. Here are the results of my tests. My measurements
are not exact but are useful for comparison purposes.
The current measurements were for total current used by
the keyer and keyboard. It seems that newer keyboards are
more energy efficient than older models.
Again, the keyer alone draws approx. 6mA at idle. Supply
voltage was approx. 13V.

KEYBOARD TEST RESULTS-

Current (keyer + keyboard) -  Model

 158mA                        Keytronic MB101
 134mA                        Gateway 2191011-XX-XXX
 132mA                        Compaq RT101
  91mA                        Zenith 163-0092-02.00
  73mA                        Hewlett-Packard C3754-60201
  66mA                        Zenith KB-5823
  15mA                        Zenith 2196002-99-001 (Maxi-Switch)
  12mA                        Dell SK-1000RE
  12mA                        Dell AT101