Shop OBEX P1 Docs P2 Docs Learn Events
Help I need a Relay driver circuit — Parallax Forums

Help I need a Relay driver circuit

lockadoclockadoc Posts: 115
edited 2010-02-15 21:46 in Propeller 1
I need to drive a 5 volt relay from a Prop pin. I'll be using the relay to gound out a Photoreistor so it forces the R/C circuit its attached to to read 0.

I tried to do the same thing with code , but go nowhere with it. confused.gif
BillS
·Louisville KY

Comments

  • Mike GreenMike Green Posts: 23,101
    edited 2010-02-13 17:51
    Look at Nuts and Volts Column #6. There's a schematic on the last page. You may want to reduce the base resistor value from 390 Ohms to 270 Ohms.

    Start on the main Parallax website and click on the Resources tab. You'll see a link to the Nuts and Volts Columns index.
  • davrandavran Posts: 12
    edited 2010-02-13 17:58
    relay driver chips can be directly connected to the pin of the micro see the attached schematic

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    "Give a lie twenty-four hours start, and it will take a hundred years to overtake it.
    " (C.F. Dixon-Johnson, British author of the 1916 book, "The Armenians," appalled over the deceitful practices of his book's subject.)

    www.tallarmeniantale.com/
    bmp
    bmp
    Noname.bmp
    495K
  • lockadoclockadoc Posts: 115
    edited 2010-02-13 20:40
    Thanks

    I will see what I have in my Parts box and see which hint i'm going to go with.

    BillS

    · Louisville KY.
  • MicrocontrolledMicrocontrolled Posts: 2,461
    edited 2010-02-14 03:10
    I have a driver circuit that works GREAT and can be made out of simple componants from your parts box. Unfortunatly I am on my phone and this schematic is not accessible. I'll get it tomorrow, and yes, it has been tested with the prop.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Computers are microcontrolled.

    Robots are microcontrolled.
    I am microcontrolled.

    SX Spinning light display·

    http://designedbymemicros.blogspot.com/
  • rjo_rjo_ Posts: 1,825
    edited 2010-02-14 03:16
    You can drive a RadioShack 5V reed relay... directly with a prop pin. Put your diode/capacitor protection up stream from there.
  • hover1hover1 Posts: 1,929
    edited 2010-02-14 04:07
    Mike,

    Why not use a ULN2803 chip shown on the previous page in the N&V column? Less parts. And it includes the needed flyback diode. Just curious. I am using The ULN2803 driving 8 solenoids at 300ma each, driven directly from the Prop. Been on the bench 24/7 for 3 weeks cycling each solenoid once every second.

    Jim
  • hover1hover1 Posts: 1,929
    edited 2010-02-14 04:10
    I just reread the top post and the OP may only need to drive one pin and may not need my 8 pin solution.

    Jim
  • lockadoclockadoc Posts: 115
    edited 2010-02-14 06:13
    thanks to all
    with this help I shoud have my project completed by Sunday night,I loom forward in Sharing with all here.

    BillS
    Louisville KY.
  • lockadoclockadoc Posts: 115
    edited 2010-02-14 06:13
    Thanks to all
    With this help I shoud have my project completed by Sunday night,I look forward in Sharing with all here.

    BillS
    Louisville KY.
  • lockadoclockadoc Posts: 115
    edited 2010-02-15 21:46
    RIO,,
    using the prop pin to drive the relay works,I placed a diode between the prop pin and the relay coil,but what do you mean by the capacitor protection. None of the circuit diagrams I've seen use one.

    Other than that My project is completed , just have to work on the documentation before uploading it.

    BillS
    Louisville KY
Sign In or Register to comment.