Yes, I thought of that one. I inspected several calculators and was not
able to come up with a reasonable way to connect to the conductive patterns
on the switch plane. In the ones I've looked at, the entire calculator
circuit is printed on a piece of flexible clear plastic, maybe a couple of
mils thick. The calculator's single IC is mounted on that same plane. A
couple of discrete components that are used are pressed against conductive
pads on the plastic plane and held in place by the plastic case. I was
hoping to find something that actually had a small connector for the key
pads, but no luck so far. The other possibility is to try a discarded TV
remote control. I'll have to tear into one of those and see if there's any
way to connect to the traces coming from the key pads.

K8AC


"Eric Snyder" wrote in message
m...
How about making your own? I see cheap credit card sized calculators
on a regular basis at the thrift store for around $1.00 or less. Just
use the push button switch section and place a piece of adhesive
plastic with the switch functions in the appropriate places. Of
course, a little experimenting and surgery of the calculator will be
required.

Eric N7DLV


"Floyd Sense" wrote in message
...
I'm looking for a membrane switch assembly a bit smaller than the usual
keypad - no wider than 2". A search of the web and usual places turned
up
nothing. It seems that most of these are custom made for specific
devices.
Anyone know of a source of surplus membrane switches?