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Pulsing Relay — Parallax Forums

Pulsing Relay

flomingoflomingo Posts: 2
edited 2009-05-03 04:59 in General Discussion
Hi Parallax people,
just joined the forum. I'm trying to control a CPU fan with a relay triggered by a stretch sensor. I have my circuit set up like this:
relay_schematic.jpg

Right now the stretch sensor isn't attached,
however when I power the circuit it just pulses
like in this video:
www.vimeo.com/4446982

Any ideas?
Thanks!
Jessica

burger.gif

Comments

  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2009-05-02 21:43
    Are you sure you have adequate power on your 5V line to power the relay? Also, do you have adequate filter and bypass caps on the 5V supply? I suspect that triggering the relay is pulling your 5V supply down, which causes the micro to reset.

    -Phil
  • Beau SchwabeBeau Schwabe Posts: 6,568
    edited 2009-05-03 04:02
    flomingo,

    Phil Pilgrim (PhiPi)·is correct, the power supply that you are using for the PIC in turn to drive the relay may not be adequate.· Why not omit the Relay and drive the CPU fan directly from the transistor?

    attachment.php?attachmentid=60591·

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Beau Schwabe

    IC Layout Engineer
    Parallax, Inc.
    FAN.JPG
    440 x 408 - 22K
    FAN.JPG 21.7K
  • flomingoflomingo Posts: 2
    edited 2009-05-03 04:59
    Hey thank you guys! I switched out the 9 volt i was running through the 5 V regulator and now everything works peachy. Sometimes its just the stupid easy things you gloss over. Thanks again!
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