Palm Keyboard interface board - (3/4/2004) - with an
example PIC based Morse code keyboard application
Palm Keyboards for the m100, III and VII models of the Palm PDA are
available on the surplus market
( Ebay example )
for around $20 postpaid. These
keyboards are unusual in that they fold up into a compact box about
the size of two Altoids tins. The Palm Keyboards also use very little
power. The keyboards communicate with the Palm PDA using
serial (RS-232) communication. Both their size and low power usage make them ideal
for QRP ham radio applications. One obvious application is as a
Morse Code keyboard. However there is one problem with these
keyboards: they do not use a standard 9 or 25 pin D connector as most
serial interfaces do. The Palm Keyboard interface board is an inexpensive
way to try out these keyboards with your own PIC or other hardware. I've
posted a simple PIC based Morse keyboard application using this circuit
board along with a PIC and a few other parts housed in an Altoids tin
(note that the PIC is NOT on the board for sale, it's on some perf board).
See the source code
and pictures of this example project at the bottom of this page
5/15/2008 - note that the board has sold out.
One problem: it will be necessary for the purchaser to fabricate a small
housing using scrap pieces of circuit board. This housing is used to
hold the interface board against the Palm Keyboard connector. Pictures
and diagrams of this housing are shown at the bottom of this page.
One other usage of this board is as an RS-232 level converter circuit.
The ST232a IC is used along with 5 caps (and a machine pin socket) to
convert from logic level signals to RS-232 level signals.
if there are any questions on this board.
board size: 1 3/8 by 1 1/2 inches
2mm contact fingers
for Palm m100, III, VII series keyboard
Downloadable files for Palm Keyboard interface board
The Acrobat files of complex diagrams (like the schematic) may not
view well on your computer screen - suggestion: use the magnifier to zoom in
for better detail or print out the file.
(Right click any link below, then select "save target as" to save the file to your PC.)
Think Outside hardware reference doc - reference info
on the Palm m100/III/VII keyboard
palm1sch.pdf (36k) - an Acrobat file of the RS-232 schematic
palmhous.pdf (10k) - an Acrobat file of the Palm connector housing
palmkeyb.pdf (12k) - an Acrobat file of the Palm Keyboard PIC Morse keyboard hardware
palm3x.asm (50k) - PIC source code for Palm Keyboard PIC Morse keyboard hardware
palmopen.jpg (43k) - a picture of the Palm Keyboard PIC Morse keyboard hardware
palmclos.jpg (38k) - another picture of the Palm Keyboard PIC Morse keyboard hardware
palmbdtp.jpg (31k) - a top view picture of the Palm Keyboard interface board
palmbdfr.jpg (15k) - a front view picture of the Palm Keyboard interface board