Assignment 5 – Treasure Hunt for Cheapskates

Flex Sensors

Buy an “out of spec” flex sensor for $4:
Or, request a free sample (FLX-01):

Fabric/Stretch Sensor
For large quantities, buy stretch conductive fabric for $60 per linear foot (52″ wide) and Velostat anti-static film for $1.95 a foot (36″ wide) from people who are worried about EMF protection…
…and make your own fabric stretch sensor:
Then, sell your left over sensors on Etsy for a profit, like this girl is doing (or, for the less entrepreneurial, just buy from her):[]=tags_exact

Electroluminescent Wire
Buy overstock EL wire for $0.88 a foot (min 100 feet)
Or, to get it for free, find and mug Daft Punk for their jackets

Alcohol Sensor
Buy a digital alcohol breath tester analyzer off eBay for $1+$1.54 shipping and remove its sensor for individual use
Or, if that isn’t your cup of tea, just buy an alcohol sensor directly for $6.90

There’s a sale on large tubular solenoids right now at goldmine:

Linear Actuator
Want to save money? Sacrifice power!
This tiny, cheap ($10) linear actuator is powered mechanically by SMA:
Or, just order directly from a Chinese supplier through Alibaba:

FIber Optic
Just using it for its aesthetics? Cheat and use fishing wire ($4 a spool)
For a slightly more “polished” look try sideglow plastic fiber ($3 a foot)
Actually want to transmit data? This kit looks pretty cool ($25)

Tiny potentiometer
Theoretically, one could find a free broken DVD player or Xbox and remove the “trimmer” potentiometer used to control laser strength (link is for a random DVD player):
Or, in a pinch, just buy one from “The Shack”

Conductive fabric
Whoops, I covered this already in fabric/stretch sensors. Just swing by the
EMF-fearing guys’ shop again to buy this in bulk:

Thermochromic Paint/Dye
For bulk, buy thermochromic pigment ($45 creates a quart of paint).
This can, again, be purchased from Chinese suppliers for enormous projects.
Just need a small surface (crystal) and not a paint? Request a free sample!

Nitinol/SMA wire
Need some Nitinol? Take it from an old underwire bra! The wire in underwire bras is often Nickel titanium.
Or, again, save money by totally sacrificing power. A super thin Nitinol wire (36″ long) can be purchased for $1.22 from SmallParts

Conductive Paint
Add graphite powder to liquid tape and Tuloul solvent to create your own conductive paint. Total cost shouldn’t be above $10 for a significant volume.
Graphite powder and Tuloul are both available at hardware stores.

Neodymium Magnet
Need a free neodeodymium magnet and not picky about its size or shape? Take one out of an old hard drive. Should be easy if you live near a computer science department.

Copper tape/foil
For a cheap price, look for an application where people need a large or widely variable amount of the stuff. (That goes for most of these materials, actually.)

One such application is boating, which sells a foil for $1 a foot:

For convenience, gardeners use copper tape to prevent snails from getting into their plants. Thus, a good, local source of such tape is a local hardware store or gardening department.

Tilt sensor
Analog Devices will provide free samples of tilt sensors:
Or if precision isn’t critical, just use a metal ball switch ($2 from Adafruit):

Peltier Junction
The trick here is to realize that a peltier can function as an electric-powered cooling device. If you want a peltier for cheap, look into people’s beer and wine cooler projects (assuming, of course, you need that much power) – or just find a clearance or free USB drink chiller like this one (but not at this price):
For cheapest component price, just buy the peltier unit directly, such as through these guys (for $6.75)

As for “most bizarre component”, I’m going to have to go with the “Blimpduino board” – (which it seems can be done with a normal arduino). It turns your Arduino…into a blimp. Right. Ok. Why not, I suppose?


One Response to “Assignment 5 – Treasure Hunt for Cheapskates”

  1. Cherrick Gordon Says:

    I am looking for a simple fabric pressure sensor for a toy I am building. It doesn’t have to be very accurate, it only needs to detect a firm touch to complete a simple light circuit. Any ideas where I might find such a sensor to buy.?

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