Assignment 5 – Treasure Hunt for Cheapskates

Flex Sensors

Buy an “out of spec” flex sensor for $4:
http://www.imagesco.com/sensors/flex-sensor.html
Or, request a free sample (FLX-01):
http://www.spectrasymbol.com/typo3/site/en/quotes-samples.html

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…
http://www.lessemf.com/fabric.html
http://www.blockemf.com/catalog/product_info.php?cPath=762&products_id=5247
…and make your own fabric stretch sensor:
http://www.instructables.com/id/Flexible-Fabric-Pressure-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):
http://www.etsy.com/view_listing.php?listing_id=31589985&ref=sr_gallery_2&&ga_search_query=sensor&ga_search_type=all&ga_page=&order=&includes[]=tags_exact

Electroluminescent Wire
Buy overstock EL wire for $0.88 a foot (min 100 feet)
http://www.elbestbuy.com/saleitems.html
Or, to get it for free, find and mug Daft Punk for their jackets
http://www.enlighted.com/pages/daftpunk2007.shtml

Alcohol Sensor
Buy a digital alcohol breath tester analyzer off eBay for $1+$1.54 shipping and remove its sensor for individual use
http://cgi.ebay.com/Digital-Alcohol-Breath-Tester-Analyzer-Breathalyzer-159_W0QQitemZ320376329185QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item4a97ead3e1&_trksid=p3286.c0.m14#ht_4598wt_1050
Or, if that isn’t your cup of tea, just buy an alcohol sensor directly for $6.90
http://www.futurlec.com/Gas_Sensors.shtml

Solenoid
There’s a sale on large tubular solenoids right now at goldmine:
http://www.goldmine-elec-products.com/prodinfo.asp?number=G16829

Linear Actuator
Want to save money? Sacrifice power!
This tiny, cheap ($10) linear actuator is powered mechanically by SMA:
http://www.sparkfun.com/commerce/product_info.php?products_id=8782
Or, just order directly from a Chinese supplier through Alibaba:
http://www.alibaba.com/wholesalers/Linear%2BActuator-wholesalers.html

FIber Optic
Just using it for its aesthetics? Cheat and use fishing wire ($4 a spool)
http://www.cockeyed.com/incredible/fiber/fiber1.php
For a slightly more “polished” look try sideglow plastic fiber ($3 a foot)
http://www.fiberopticproducts.com/Sideglow.htm
Actually want to transmit data? This kit looks pretty cool ($25)
http://www.makershed.com/ProductDetails.asp?ProductCode=MKEL8

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):
http://www.fixya.com/support/t254066-toshiba_sd_c2512_reading_dvd_but_not_cd
Or, in a pinch, just buy one from “The Shack”
http://www.radioshack.com/product/index.jsp?productId=2062301

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:
http://www.lessemf.com/fabric.html

Thermochromic Paint/Dye
For bulk, buy thermochromic pigment ($45 creates a quart of paint).
http://www.paintwithpearl.com/colorchangestore.htm
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!
http://www.colorchangeline.com/Color%20Change%20Line%20Sample%20Request%20Form%2045781.htm

Nitinol/SMA wire
Need some Nitinol? Take it from an old underwire bra! The wire in underwire bras is often Nickel titanium.
http://www.ultimateniti.com/apparel.cfm
Or, again, save money by totally sacrificing power. A super thin Nitinol wire (36″ long) can be purchased for $1.22 from SmallParts
http://www.smallparts.com/Nitinol-Wire-SuperElastic-Nickel-Titanium/dp/B001DEGVAU?ie=UTF8&qid=1254248756&pf_rd_r=1XG885SR7SZ25MRKAW4D&pf_rd_p=467590031&pf_rd_i=0&sr=1-1&pf_rd_s=center-3&pf_rd_m=AIUBT5HP6PMAF&pf_rd_t=301

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.
http://www.instructables.com/id/SEOH3GFFABRWUOD/
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.
http://en.wikipedia.org/wiki/Neodymium_magnet
http://www.ehow.com/way_5328488_buy-neodymium-iron-boron-magnets.html

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:
http://www.defender.com/product.jsp?path=-1%7C344%7C301236%7C69608%7C303332&id=28788

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.
http://www.amazon.com/Ambrands-15Slug-Snail-Copper-715/dp/B000QD3

Tilt sensor
Analog Devices will provide free samples of tilt sensors:
http://www.analog.com/en/sensors/inertial-sensors/products/overview/over_inertial_sensing_technology_evaluate/fca.html
Or if precision isn’t critical, just use a metal ball switch ($2 from Adafruit):
http://www.adafruit.com/index.php?main_page=product_info&cPath=35&products_id=173

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):
http://www.usbgeek.com/prod_detail.php?prod_id=0592
For cheapest component price, just buy the peltier unit directly, such as through these guys (for $6.75)
http://www.suntekstore.ca/100w-tec-thermoelectric-cooler-peltier-12v.html

—————————
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?
http://www.makershed.com/ProductDetails.asp?ProductCode=mkca1

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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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