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wire up to car — Parallax Forums

wire up to car

driftaholicdriftaholic Posts: 6
edited 2009-08-15 22:20 in BASIC Stamp
okay finally finished the code for my solenoid controller but now i just need to wire up to the car
okay what would i do to wire it up to power off of the car and what transistor would i use to use the output of the board to control 12vdc solenoid
i will put up the pull of it in a lil

Comments

  • Mike GreenMike Green Posts: 23,101
    edited 2009-08-09 06:05
    For controlling a 12V solenoid, look at Nuts and Volts Column #6. Go to the main Parallax webpage and click on the Resources tab. On the list you get there will be a link called Nuts and Volts Columns. Click on that to go to the index.

    For powering a Stamp off the car's electrical system, consider using a 9V regulator like the LM7809. The datasheet for the regulator (search the web for it) shows some typical hookups and recommended filter capacitor values. On the input side, you'll need something with a 25V rating. On the output side, a 15V or 16V rating will do. Use a fuse on the input side and a diode (like a 1N4001) to protect against an accidentally reversed battery. The 9V output of the regulator would go to the Stamp's regulator.
  • driftaholicdriftaholic Posts: 6
    edited 2009-08-09 11:24
    i tried that i just want a part number of a transistor that would work
  • LeonLeon Posts: 7,620
    edited 2009-08-09 12:02
    Solenoid details?

    Leon

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  • driftaholicdriftaholic Posts: 6
    edited 2009-08-09 21:17
    12vdc 23-25 ohms
  • Mike GreenMike Green Posts: 23,101
    edited 2009-08-09 21:23
    By Ohm's Law, this draws a little over 600mA. One channel of a ULN2003 can handle this (just barely). You can parallel two channels to comfortably handle this solenoid. The ULN2003 or ULN2803 even has flyback diodes built-in. The Nuts and Volts Column I mentioned also discusses the use of this part.
  • driftaholicdriftaholic Posts: 6
    edited 2009-08-09 21:30
    whats a flyback diode
    and how would i connect this to the solenoids with my bs2

    right now i have pin 6,8 to two resistors to two leds (simulating the solenoids) to the vss part of the board so is vss ground or what and if i had this wired in the car how would i need to connect the stuff
    thanks
  • Mark DietrichMark Dietrich Posts: 7
    edited 2009-08-13 00:45
    I wonder if the pull-in current of the solenoid wouldn't be a lot higher?
  • Carl HayesCarl Hayes Posts: 841
    edited 2009-08-15 22:20
    Mark Dietrich said...
    I wonder if the pull-in current of the solenoid wouldn't be a lot higher?
    No, it wouldn't.· Steady state for a solenoid is always the stalled condition, so steady state is the maximum-current condition.· During pull-in (while physical motion is occurring), the current will always be lower than steady-state because of the back EMF that results from the motion of the solenoid piston.

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    · -- Carl, nn5i@arrl.net
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