DIY Force Sensitive Resistor (FSR)

Step 5 Notes

Variations

• Use it to Dim an LED (video + code)
• Use it to Make some noise (video)
• Try different kinds of foam (test resistance across the foam first to make sure it's conductive)
• Cut unusual shapes
• Test different foam configurations (e.g.: multi-layered foam)
• Test different plate materials (e.g.: aluminum foil on cardboard/plastic/wood)
• Make humongous FSR arrays

Links

SensorWiki FSR page explains FSR theory and use, with examples
Protolab explanation of FSR use in the context of other sensors

Thanks to Dane Kouttron and Zach Barth for introducing this technique to me, and leaving a few FSRs around the eclub.

Comments

[dbsoundman]

For those of you who have actually built this, what did you use to protect the copper? Conformal coating spray is pretty expensive, and I plan on trying to make rather long FSRs so coating with solder might be a bit difficult as well. Suggestions?

[martzsam]

Liquid plastic coating. Like plasti mix.

[Emilious]

what's liquid thin?

[Chromacon]

A few years ago I used a fine grade Pressure Sensitive Material to make an 18 channel control board for lights. I had Vellman dimmers that ran on a 0-10 V control voltage, and I made 18 pads similar to these to make voltage dividers to control them. The guy who gave me the PSM as an industrial sample died though, and I have no supply for more as needed. I am really glad to find the suggestions in this project!

[kylemcdonald]

I'm glad to help/provide a place for links to congregate.

Be sure to check out Hannah's work too: http://www.instructables.com/member/Plusea/ She does a ton with resistive material, and has some links to suppliers.

[SoakedinVancouver]

Quick and dirty! Bye the way, always clean the whole of the copper clad board, and then coat with liquid thin, or with a thin coat of solder. Copper has the bad habit of corrding, and once it is, it does not conduct very well! Your notes are a very good add-on as well, good work!

[Polymorph]

Lead solder corrodes quickly, too. Not sure about the new lead-free solders. Tin plating might be better. Or silver, since even oxidized silver conducts.

[thesku11s]

Im new to this hobby, never had a micro controller so have no idea where to get conductive foam? Any sources for project parts like this? A cool tutorial by the way, thanks for putting it up.

[Polymorph]

You want "carbon impregnated conductive foam". It should be black. The pink and blue stuff is only very, very slightly conductive. Some possible sources: Digikey Mouser Altex Jameco Newark Arrow Just put WWW before and COM after for their websites.