[CART360] Magnetic Sensor

[Craig Fahner]

Lee Valley has really good Rare Earth magnets that I've used with Hall
Effect sensors. The Ottawa store ships to Montreal.

http://www.leevalley.com/hardware/page.aspx?c=2&p=42348&cat=3,42363

c

On Mon, Oct 19, 2009 at 9:27 PM, Vincent Leclerc
<vincentlecler at gmail.com> wrote:
> This is the hall effect sensor I showed in class:
> http://www.allegromicro.com/en/Products/Part_Numbers/3213/3213.pdf
>
> They are omnipolar, which means they can be triggered by either a north or
> south magnetic field.
> Digikey sells them for $1.76.
> http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=620-1043-ND
>
> For HB LEDs, go to http://ledz.com/?p=led.power
> They have 3W (3.5V, 700mA) LEDs that will blind you. They might have a
> minimum order qtt so you may want to try eBay for the same type of product.
> http://business.shop.ebay.ca/Business-Industrial-/12576/i.html?_nkw=3w+led&_catref=1&_fln=1&_sac=1&_trksid=p3286.c0.m282
>
> DON'T FORGET to heatsink these LEDs. They emit a lot of heat and it needs to
> be properly dissipated with an aluminum heatsink. If you don't, they will
> last only several hours.
>
> You drive them with a mosfet and use a current limiting resistor like a
> normal LED with the formula V=RI.
>
> In that case at 5V:
>
> 5 - 3.5 = R * 0.7
> 1.5 = R * 0.7
> R = 2.1 Ohms
>
> You will need a special power resistor, because so much current will go
> through it. With the formula P = VI we get:
>
> P = 1.5 * 0.7
> P = 1.05 Watt
>
> So to be safe, you need a 3 Ohm, 2 Watt resistor like so:
> http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=3.0W-2-ND
>
>
> Vincent
>
>
>
> On Mon, Oct 19, 2009 at 5:20 PM, Alec Mathewson <alec.mathewson at gmail.com>
> wrote:
>>
>> Hey Vincent
>>
>> I want to buy a couple Magnetic sensors and strong LED's I can strobe.
>> Anything particular I need to consider regarding the ones you had posted?
>>
>> Alec
>>
>
>
>
> --
> Vincent Leclerc
>
> Creative | Technical Director, ESKI Inc.
> 1751 Richardson, Suite 4311
> Montreal, QC, Canada, H3K 1G6
> http://eskistudio.com/
> http://maps.google.com/maps?q=eski+montreal
>
> Part-time Faculty, Design and Computation Arts
> Concordia University, Montreal, QC, Canada
> http://hybrid.concordia.ca/~cart360_vincent/
>
> office: 514-510-5777 #221
> fax: 514-510-5888
> cell: 514-293-9358
> http://vincentleclerc.com
>
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