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Topic: on/off switches in resistor voltage divider (Read 12536 times) previous topic - next topic

fungus


Yes, a great idea.
Digital ---> analog ---> digital ;)


The idea is that the path is narrower in the middle....
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fungus

#16
Jun 18, 2014, 08:45 am Last Edit: Jun 18, 2014, 08:53 am by fungus Reason: 1

If I am using each pins; that would be need maybe 400 pins,
...
I need double values.


This is unlikely to work.

It might sound good in theory, but ...

Why don't you tell us what you're trying to make/achieve, not what you're doing. That way nobody will waste any time giving non-applicable answers.

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Grumpy_Mike

Quote
that would be need maybe 400 pins

That implies you need a 20 by 20 matrix of switches.

fungus

#18
Jun 18, 2014, 11:12 am Last Edit: Jun 18, 2014, 11:17 am by fungus Reason: 1

Quote
that would be need maybe 400 pins

That implies you need a 20 by 20 matrix of switches.


I spotted that, too!

Sounds to me like somebody's trying to make a MIDI controller (or something similar).
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vffgaston


Qwseyvnd

#20
Jun 19, 2014, 04:56 pm Last Edit: Jun 19, 2014, 05:12 pm by Qwseyvnd Reason: 1
See this image:
http://www.airliners.net/photo/Aeroflot/Ilyushin-Il-62/1084219/L/&sid=88b5aa0092f257b39b8336e8d937c49c
Is that possible: Detect which switch toggle switch are used in one pin?

It is possible through this guide:
http://arduino.cc/en/Tutorial/TwoSwitchesOnePin

So, therefore, I wonder if it is possible with three and more switches ?

Grumpy_Mike


See this image:
http://www.airliners.net/photo/Aeroflot/Ilyushin-Il-62/1084219/L/&sid=88b5aa0092f257b39b8336e8d937c49c
Is that possible: Detect which switch toggle switch are used in one pin?

No way on God's Earth is it possible to read all those switches with one pin.

Two pins an a bunch of shift registers yes but one pin no.

Qwseyvnd



See this image:
http://www.airliners.net/photo/Aeroflot/Ilyushin-Il-62/1084219/L/&sid=88b5aa0092f257b39b8336e8d937c49c
Is that possible: Detect which switch toggle switch are used in one pin?

No way on God's Earth is it possible to read all those switches with one pin.

Two pins an a bunch of shift registers yes but one pin no.


You said no? See here: http://arduino.cc/en/Tutorial/TwoSwitchesOnePin
It's possible. So, I wondering if it is possible with three and more.

Grumpy_Mike

If you understood how that technique worked you would know you can not do it with more than two switches. Certainly not 400.


fungus

You still haven't told us what you're trying to do.

I know how to read hundreds of switches using only two Arduino pins but I'm not going to waste time explaining the method unless I'm sure it works the way you need.
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vffgaston

Quote
You still haven't told us what you're trying to do.

I know how to read hundreds of switches using only two Arduino pins but I'm not going to waste time explaining the method unless I'm sure it works the way you need.


There is a (very old) method (in fact is a primitive DAC) to "read" many switches in an analog input. May be this is what this man (this pollo; I would say) is looking for.

(I adjoint a page of my -very old- Millman)

Grumpy_Mike

Quote
to "read" many switches in an analog input.

You can't read more switches than you have bits in the A/D converter, possibly two less, with multiple switch contacts!

This guy wants to read 400 switches!

vffgaston

Quote
You can't read more switches than you have bits in the A/D converter, possibly two less, with multiple switch contacts!

This guy wants to read 400 switches!


Absolutelly. I just tried lo give some ligth on the subject.

Regards.

fungus


Quote
to "read" many switches in an analog input.

You can't read more switches than you have bits in the A/D converter, possibly two less, with multiple switch contacts!


Probably a lot less than that in practice, the bottom two (or three) bits of your measurement will be noise, the resistors will have tolerances which will take off another 2 or 3 bits, plus you won't be able to get the exact resistor values you want to make a perfectly linear array (they don't make them in binary values).

etc., etc.

Anyway, the OP seems to have disappeared.
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