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?

--
73, Floyd - K8AC

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?

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?

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?

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?

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?

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?

"Floyd Sense" ) writes:
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

But does it have to be membrane, or are you merely looking for a small keypad?
A lot of electronics stuff uses tiny circuit board mounted push switches,
and you could salvage those and make a keypad. Usually, there is a plastic
button that rests over them for actuating the switch, but they can be
actuated directly with your finger on the button.

This might give you more flexibility, since you could arrange them as
you like, and have as many or as few as you want.

VCRs tend to have a fair number of these buttons, depending on how many
pushbuttons they have. Find one in the garbage and see if the buttons
are suitable. Inkjet printers, also common in the garbage, have them,
but not as plentiful. Old stereos, and some car radios are also a source.

The easiest way of making a flat switch panel at home would go to capacitance
switching. Pads of copper etched that can be covered if the circuit's right.
The circuitry puts a clock through there, and when you touch the pad, the
capacitance of your body delays the clock so it's not in sync with the
original, and that causes a transition on the output. Don Lancaster
discusses them in his CMOS Cookbook. It's kind of bulky for multiple
switches, since each uses a flip-flop, but I've seen other similar schemes
using multiplexers for larger numbers of "contacts", though I can't
point you to anything specific. Of course, this whole scheme requires that
extra circuitry, so it may not be the choice for small equipment.

Michael VE2BVW


"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?

"Floyd Sense" ) writes:
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

But does it have to be membrane, or are you merely looking for a small keypad?
A lot of electronics stuff uses tiny circuit board mounted push switches,
and you could salvage those and make a keypad. Usually, there is a plastic
button that rests over them for actuating the switch, but they can be
actuated directly with your finger on the button.

This might give you more flexibility, since you could arrange them as
you like, and have as many or as few as you want.

VCRs tend to have a fair number of these buttons, depending on how many
pushbuttons they have. Find one in the garbage and see if the buttons
are suitable. Inkjet printers, also common in the garbage, have them,
but not as plentiful. Old stereos, and some car radios are also a source.

The easiest way of making a flat switch panel at home would go to capacitance
switching. Pads of copper etched that can be covered if the circuit's right.
The circuitry puts a clock through there, and when you touch the pad, the
capacitance of your body delays the clock so it's not in sync with the
original, and that causes a transition on the output. Don Lancaster
discusses them in his CMOS Cookbook. It's kind of bulky for multiple
switches, since each uses a flip-flop, but I've seen other similar schemes
using multiplexers for larger numbers of "contacts", though I can't
point you to anything specific. Of course, this whole scheme requires that
extra circuitry, so it may not be the choice for small equipment.

Michael VE2BVW


"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?

"Floyd Sense" ) writes:
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

But does it have to be membrane, or are you merely looking for a small keypad?
A lot of electronics stuff uses tiny circuit board mounted push switches,
and you could salvage those and make a keypad. Usually, there is a plastic
button that rests over them for actuating the switch, but they can be
actuated directly with your finger on the button.

This might give you more flexibility, since you could arrange them as
you like, and have as many or as few as you want.

VCRs tend to have a fair number of these buttons, depending on how many
pushbuttons they have. Find one in the garbage and see if the buttons
are suitable. Inkjet printers, also common in the garbage, have them,
but not as plentiful. Old stereos, and some car radios are also a source.

The easiest way of making a flat switch panel at home would go to capacitance
switching. Pads of copper etched that can be covered if the circuit's right.
The circuitry puts a clock through there, and when you touch the pad, the
capacitance of your body delays the clock so it's not in sync with the
original, and that causes a transition on the output. Don Lancaster
discusses them in his CMOS Cookbook. It's kind of bulky for multiple
switches, since each uses a flip-flop, but I've seen other similar schemes
using multiplexers for larger numbers of "contacts", though I can't
point you to anything specific. Of course, this whole scheme requires that
extra circuitry, so it may not be the choice for small equipment.

Michael VE2BVW


"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?