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Resistance Heating — Parallax Forums

Resistance Heating

ddoudddoud Posts: 10
edited 2006-02-10 17:28 in BASIC Stamp
Hi All,

I'd like to use my BS2PE to control a resistance heating element, a piece of toaster wire, but I dont think (or want to risk) running all that current through a high pin pause low pin type command. Is there a way I can use my basic stamp to connect some other circut that would connect another set of batteries or something to the heating element for safe resistance heating? I could have a servo literally throw a switch, but I imagine theres a better way I just dont know about.

Thanks much
d scool.gif

Comments

  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2006-02-09 21:09
    You should check out the Industrial Control book.· It covers this very thing.·· You can download a PDF version of the book from our website.

    http://www.parallax.com/detail.asp?product_id=27341

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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
  • Jon WilliamsJon Williams Posts: 6,491
    edited 2006-02-09 21:10
    Sure, it's pretty easy to do -- I've attached a typical relay circuit.· The [noparse][[/noparse]base] resistor and transistor will have to be selected for the relay you intend to use.

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    Jon Williams
    Applications Engineer, Parallax
    Relay Driver.jpg
    20K
  • ddoudddoud Posts: 10
    edited 2006-02-09 21:15
    Wow! Thanks guys! I'll give it a look right now!

    tongue.gif
  • ddoudddoud Posts: 10
    edited 2006-02-10 03:39
    OK, so I've read up about relays today, and NPN gates, things i've never used, and I'll post what I've found and hope someone can comment on it further and help out.

    Basically, the resistance wire will need about 1amp to get to temperature, so the relay switch will have to be able to take 1amps of current. From what I read, this isnt a problem. I've been looking at this one: http://www.radioshack.com/product/index.jsp?pg=1&parentPage=search&cp=&productId=2062478&kw=relay&numProdsPerPage=20&tab=summary

    I'm unsure how to select the base resitor and transistor though. I guess I have access to most of these: http://www.radioshack.com/search/index.jsp?kwCatId=&kw=transistor

    Also, I tried to find more information in the book that was linked, but I didnt see any diagrams or anything that would help out. I'll look deeper tomorrow, but I thought I woud send up a flair now because Ive spent all day on it already.

    finally, the bottom pointing arrow on the diagram, is that ground? and the other is my source??

    Thanks so much,
    -d
  • Jon WilliamsJon Williams Posts: 6,491
    edited 2006-02-10 03:55
    This article may help: http://www.parallax.com/dl/docs/cols/nv/vol1/col/nv6.pdf

    And let me suggest that if you're new to electronics you may want to proceed VERY SLOWLY or find a friend (experienced with electronics, that is)·to help you with the project.· "Shotgunning" circuits is a sure way to do damage beyond your ego.· A great book to help you start understanding electronics principles and components is "Getting Started in Electronics" by Forrest M. Mims; you can find it at your favorite book store.

    One of the things you'll learn to do is "de-rate" components.· What I mean by this is that in your case, you want to run one amp through the wire.· So what you'll want to do is find relay contacts that will carry at least two amps at the voltage you intend to use.· As you can see, the relay you're looking at is probably not a good idea for the project.

    Good luck!

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    Jon Williams
    Applications Engineer, Parallax

    Post Edited (Jon Williams (Parallax)) : 2/10/2006 3:59:53 AM GMT
  • ddoudddoud Posts: 10
    edited 2006-02-10 05:45
    Thanks Jon-

    I'm in no mind to break stuff. I've lined up a friend, and I'll read your link.

    thx

    -d
  • Jon WilliamsJon Williams Posts: 6,491
    edited 2006-02-10 07:45
    Excellent -- it'll be more fun to learn with a friend, and that friend may just save you from damaging your BASIC Stamp.

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    Jon Williams
    Applications Engineer, Parallax
  • PJAllenPJAllen Banned Posts: 5,065
    edited 2006-02-10 13:43
    Jon Williams (Parallax) said...
    "Shotgunning" circuits is a sure way to do damage beyond your ego.
    Most excellent, JW.· You mind if I use that?
  • Jon WilliamsJon Williams Posts: 6,491
    edited 2006-02-10 17:28
    Be my guest!

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    Jon Williams
    Applications Engineer, Parallax
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