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"Fuzzy" push button component

A

Arne Harisson

Jan 1, 1970
0
Hi im looking for a button, the harder you press it, the less
resistance will run through the circuit, in effect a potentiometer but
with a button instead if a turning knob.

Im a newbee to the components world and was wondering if some knows
how to find such a component and if there are any tutorial online on
how to get started finding the right component etc. If someone know
the cross reference code or whatever its called ill be very happy.

thanks
 
M

Myron Samila

Jan 1, 1970
0
Arne Harisson said:
Hi im looking for a button, the harder you press it, the less
resistance will run through the circuit, in effect a potentiometer but
with a button instead if a turning knob.

Im a newbee to the components world and was wondering if some knows
how to find such a component and if there are any tutorial online on
how to get started finding the right component etc. If someone know
the cross reference code or whatever its called ill be very happy.

thanks


Well, this is an easy one.

Yamaha makes electronic keyboards, and on some models, the keys are velocity and pressure
sensitive.

I don't know exactly how they do this, I doubt it is a simple analog circuit, especially
for an 88 key electric piano.

But at least I can tell you that something like that does exist.

Where do you live? There are many switch manufacturers that would be willing to send out
a sample to you, that you can later buy from a dealer.
 
S

Sir Charles W. Shults III

Jan 1, 1970
0
A fast and cheap method is to use a piece of that black anti-static foam
and a pair of metal contacts. The greater the pressure, the lower the
resistance. You can experiment with this for starters.

Cheers!

Chip Shults
 
A

Arne Harisson

Jan 1, 1970
0
I live in Mountain View, CA.

Would a dealer send out a sample to a hobbyist like me?
 
A

Arne Harisson

Jan 1, 1970
0
Look at force sensors, like this:
That component was cool!

This is what im trying to do.
Im trying to detect if something is over the thing im trying to make.
it has to be a device that gets pushed down. e.g. an optical solution
wouldnt work.

I guess a piezo electric solution would work since it can be made very thin
(I need something that is 1-1.5cm thick).
I think smart houses uses this in floors that can detect how much the person
standing on it weighs and where he is going and where he as been. But i dont
need that advanced feature, basically on or off with a couple of steps in
between that could be adjusted electronically/programmatically for a
threshold , e.g detect when (some signal voltage/resistance) more than x.
The range of weight is approx between 2-20 kg

thanks
 
J

JeffM

Jan 1, 1970
0
Yamaha makes electronic keyboards,
and on some models, the keys are velocity and pressure sensitive.
I don't know exactly how they do this
Myron Samila

Baldwin used [use?] wire key contacts
and conductive elastomers as collectors (~bus bars).
You didn't get the explosive attack lik you do with Hammonds,
as the gradual-make contact softens it up.

Chip Shults' suggestion has the advantage of being free.
Use the conductive foam that they ship your ICs in
and sandwich it between stiff metal plates.
 
B

Bill Sloman

Jan 1, 1970
0
Myron Samila said:
Well, this is an easy one.

Yamaha makes electronic keyboards, and on some models, the keys are velocity > and pressure sensitive.

I don't know exactly how they do this, I doubt it is a simple analog
circuit, especially for an 88 key electric piano.

As far as I know, velocity sensitive piano keys incorporate two
switches, and the key velocity is sensed by measuring the time delay
between the first key-closure and the second. This can be done quite
easily and cheaply in the digital domain.

The U.K. hobbyist magazine published a "build your own electric piano"
project more than twenty years ago that - IIRR - worked on this basis.
 
J

Jan Panteltje

Jan 1, 1970
0
Hi im looking for a button, the harder you press it, the less
resistance will run through the circuit, in effect a potentiometer but
with a button instead if a turning knob.

Im a newbee to the components world and was wondering if some knows
how to find such a component and if there are any tutorial online on
how to get started finding the right component etc. If someone know
the cross reference code or whatever its called ill be very happy.

thanks
I see pressure sensors in the conrad catalog ( www.conrad.nl ),
page 781 a, whole range, itt says (translated from Dutch):
10g - 10kG gives 2 Mohm to ca 3 kOhm
There is a whole range, some type numbers:
FSR-149NS 8 mm diameter (these are foil type sensors), 4,85 Euro
oder nr 18 23 89 44
(catalog page 781 with the other sensors).
That one is 8mm diameter, , the bigest one is 46x46 mm hehe
They specify 10 000 000 activations.
Have not tried one but for that price it is easy to find out.
You will need a (knob) construction on top of the foil, it has soldering
wires it seems.
 
D

Don Lancaster

Jan 1, 1970
0
Arne said:
Hi im looking for a button, the harder you press it, the less
resistance will run through the circuit, in effect a potentiometer but
with a button instead if a turning knob.

Im a newbee to the components world and was wondering if some knows
how to find such a component and if there are any tutorial online on
how to get started finding the right component etc. If someone know
the cross reference code or whatever its called ill be very happy.

thanks

http://www.interlinkelectronics.com/

Or, for a quick and sloppy answer, use a piece of IC protective foam.
Or better foams available at outrageous cost from Emerson & Cuming.
Avoid the silver ones; they stop working as soon as they get a
fingerprint on them.

We quickly sold out of these by advertising them on eBay as tinfoil hat
liners.

We offer component finding services per http://www.tinaja.com/info01.asp

--

Many thanks,

Don Lancaster
Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
voice: (928)428-4073 email: [email protected] fax 847-574-1462

Please visit my GURU's LAIR web site at http://www.tinaja.com
 
J

Jerry Greenberg

Jan 1, 1970
0
The best way to do this at a resonable cost is to get a varible
resistor, and mechanicaly couple it to a spring loaded lever. This
would require some custom work to have the pot rotate as the lever is
pushed in.

Another approach is to get a slider pot, and mechanicaly couple it to
a lever that is spring loaded.

There are some varible resistance type push buttons on the market, but
their prices are very expensive. If this is for a professional type
job, then I would suggest going with something that is commercialy
made. I cannot recall the manufactures at the moment.


Jerry Greenberg
http://www.zoom-one.com
 
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