The Story of BZ1FB Keyer
In December 1994 when the third class licence Ham operators (BD prefix call)
became quite active in China, some of the local BDs told me that it was so
difficult to master sending CW using a streight key, so I suggest them trying
the keyer, that's a easy way to operate CW. But the problem we were facing
is that the circute found in ARRL or other organization's handbook seems too
complex, the famous 8044 chip is a good choice, but it is too expensive and
can be hardly found in China. I began to look for a way to build a simple and easy
to constructed keyer. The Motorola MCU MC68HC705K1P is a very small single chip
microcontroller, only 16 pin DIP, and cost about 4 US$ local. Nice to make a keyer with it,
OK let me
rock and roll. My idea is to simulate the 8044 keyer chip, dot and dash memory,
auto word space and a speed meter. The first beta design use a up and down
button to control the speed, later when I plan to add weight control, I found
no IO port available, so I change the design, using the dot and dash paddle to
control the speed, of course add a switch to indicate wether the paddles
are in really paddle condition or speed adjust condition. All done, the keyer
is working, but it seems the power dissipation is a bit high, that is because
the microcontroller is runing all the time, so I modified the software and the
hardware using the stop and wait technology. GOOD! The keyer now can be powered
by two set of Alkaline battery for operating at least two months. When I was
making this keyer, I was holding the BZ1FB callsign, so I name the keyer as
BZ1FB Keyer, Thanks CRSA for making it as a KIT. Here I give my design as a FREEWARE
to those Hams who want to build the keyer also. If you really want to pay me,
send me a book upon ham radio.
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