Force sensitive resistive pad - good for a wah-wah maybe?

[frequencycentral]

I just spotted this via a thread on electro-music.com:

"This is a force sensitive resistor with a square, 1.75x1.5", sensing area. This FSR will vary its resistance depending on how much pressure is being applied to the sensing area. The harder the force, the lower the resistance. When no pressure is being applied to the FSR its resistance will be larger than 1MΩ. This FSR can sense applied force anywhere in the range of 100g-10kg."

Strikes me it might make for an interesting wah experiment?

Here's the link: http://www.sparkfun.com/commerce/product_info.php?products_id=9376

Here's the electro-music.com thread, with a very simple suggested interface circuit: http://electro-music.com/forum/viewtopic.php?t=37239

[wavley]

You think that's how this thing works? http://www.jacquespedals.com/index.php?page=products&product=trinity I've never seen one in person

[frequencycentral]

You think that's how this thing works? http://www.jacquespedals.com/index.php?page=products&product=trinity I've never seen one in person

I think that's air pressure controlled maybe? Like this: http://experimentalistsanonymous.com/diy/Schematics/Full%20Synths%20Drum%20Synths%20and%20Misc%20Synth/Synblo.pdf

[frequencycentral]

Or hows about an alcohol-breath-wah: http://www.sparkfun.com/commerce/product_info.php?products_id=8880

Fart-wah: http://www.sparkfun.com/commerce/product_info.php?products_id=9404

[wavley]

And people wonder why I have a meal of Beer and Chili before a gig.  Though it makes recording in a basement suck as we found out a few weeks ago when 2/3 of the band judged a chili cook off

[Top Top]

This was a long time ago that I saw this, so I could be mis-remembering something, but I thought I remember seeing something about using the type of foam that IC's are shipped in (or something similar) to make variable resistor pressure sensitive pads.

Edit:

I knew I wasn't crazy. Here is an example of what I was thinking of... http://www.instructables.com/id/DIY-Force-Sensitive-Resistor-FSR/

[Skruffyhound]

I read that too Top Top, I believe it was an R.G. suggestion for achieving a variable resistance pressure pad, the downside being that the foam gets squished fairly quickly and has to be replaced.

[Skruffyhound]

So maybe R.G. reads instructables..... or their authors read his comments
Good links in this thread though

[Ripthorn]

You could use one for a burst box.  When you tap it hard, you get  a burst.

[puretube]

FSR and other 3-letter words don`t get caught by the search-function... 

[frequencycentral]

FSR and other 3-letter words don`t get caught by the search-function...  

Q: Parts list? Vero layout?
A: DIY?

[petemoore]

  I didn't read about reliable much, but the sheets talked consistancy and actuator accuracy quite a bit.
 Looks perfect for knowing the exact pressure to Burst Box.
 And would certainly make a wha wah, whether the taper comes out right is interesting prospect for this device, quite a few application notes and guides to different functions some are certainly interesting.

[puretube]

link`d

[frequencycentral]

link`d

Great link, thanks Ton! I still want to try it though.......

[puretube]

link`d

Great link, thanks Ton! I still want to try it though.......

It`s one of these...

[frequencycentral]

link`d

Great link, thanks Ton! I still want to try it though.......

ya`ain`t got "Analoguru`s" schemo?

I wonder if you will show us a schematic...

Why? haven`t you caught it from this so-called gentleman`s site yet ?:
http://analogguru.an.ohost.de/temp/EH_Tubezipper_factory.pdf

Oooops.... an error occurred: above link isn`t the T-Z schemo, but
his offering of  his tube-E-Q drawing...

[puretube]

link`d

Great link, thanks Ton! I still want to try it though.......

ya`ain`t got "Analoguru`s" schemo?

I wonder if you will show us a schematic...

Why? haven`t you caught it from this so-called gentleman`s site yet ?:
http://analogguru.an.ohost.de/temp/EH_Tubezipper_factory.pdf

Oooops.... an error occurred: above link isn`t the T-Z schemo, but
his offering of  his tube-E-Q drawing...

EEEKKK   LEDz and FETz in the cathode leadz - THAT ain`t NO PURE-TUBE !!!

[R.G.]

One problem you have to address with FSRs is pressure overload. They're good between 100g and 10kG; no problem there.

But we've had problems with people breaking off the activators of stomp switches and the shafts of pots by stomping on them; and I've seen more than one guitarist standing, single-footed on a wah pedal. For a reliable device, you need to ensure that the FSR is not damaged by pressures of 10kg up to maybe 100kg.

[Top Top]

One problem you have to address with FSRs is pressure overload. They're good between 100g and 10kG; no problem there.

But we've had problems with people breaking off the activators of stomp switches and the shafts of pots by stomping on them; and I've seen more than one guitarist standing, single-footed on a wah pedal. For a reliable device, you need to ensure that the FSR is not damaged by pressures of 10kg up to maybe 100kg.

For DIY and home use I could see them as fine, but yea, for other people to abuse... that's a different story.

[Processaurus]

One problem you have to address with FSRs is pressure overload. They're good between 100g and 10kG; no problem there.

But we've had problems with people breaking off the activators of stomp switches and the shafts of pots by stomping on them; and I've seen more than one guitarist standing, single-footed on a wah pedal. For a reliable device, you need to ensure that the FSR is not damaged by pressures of 10kg up to maybe 100kg.

Puretube, have you had any FSR's fail/get out of calibration in your pressure wah prototypes?

For a DIY thing, the easy way out would be to have a comparator driving an LED to show if it's overloading, it'd be up to the responsible adult to temper their enthusiasm...