Announcement

Collapse
No announcement yet.

delay off circuit? (not for psu)

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • delay off circuit? (not for psu)

    Hey everyone,

    I am going to be installing a rearview cam that will go on automatically when i put the car in reverse but i want to also be able to touch a momentary (qtouch) switch and have the cam turn on for 20-30 seconds. Does anyone know how to do this? I want this switch to be independent of the computer so this will have to be a hardware based solution.


    Thanks,
    `S
    New System in progress:
    M10k
    Phaze TD1500 ~> Dynaudio MD130
    Phaze TD1500 ~> Seas g18rnx/p
    Zapco Ref 500.1 ~ 12" tc-9
    Behringer DCX2496 ~ Envision Electronics psu
    Transflective Xenarc

    My Car Pc Install
    My Boat Pc worklog

  • #2
    You should be able to do that with a simple 555 timer circuit. A microcontroller is another option.
    2004 4runner

    Comment


    • #3
      Originally posted by rando
      You should be able to do that with a simple 555 timer circuit. A microcontroller is another option.

      Thats what i'm looking into right now, but trying to find what i need is a llittle confusing. I'm pretty new to building with ic's but i'm not that bad at it. Do you know of any sites that have a good schematic and write up?
      New System in progress:
      M10k
      Phaze TD1500 ~> Dynaudio MD130
      Phaze TD1500 ~> Seas g18rnx/p
      Zapco Ref 500.1 ~ 12" tc-9
      Behringer DCX2496 ~ Envision Electronics psu
      Transflective Xenarc

      My Car Pc Install
      My Boat Pc worklog

      Comment


      • #4
        i think i found it...20 seconds but it uses a 4013 flip/flop ic... still looking for a simpler 555 ic schematic
        http://www.discovercircuits.com/PDF-...ffwtimeout.pdf
        New System in progress:
        M10k
        Phaze TD1500 ~> Dynaudio MD130
        Phaze TD1500 ~> Seas g18rnx/p
        Zapco Ref 500.1 ~ 12" tc-9
        Behringer DCX2496 ~ Envision Electronics psu
        Transflective Xenarc

        My Car Pc Install
        My Boat Pc worklog

        Comment


        • #5
          That looks pretty straightforward, I doubt you're going to find much simpler than that.

          Comment


          • #6
            Yep, Rando's right. You should use a 555. Look up "monostable one-shot multivibrator" on google and you should get some simple circuits like that. About 8 years ago I built a simple circuit to put my power windows down using a single touch button. It was an old Camaro with power windows, but they were slow and I hated having to hold both buttons down while they slowly came down (I lived in Florida and the car had Glass T-Tops). Anyway, long story short, using a 555, and a Capacitor/Resistor combo (for timing) you can create a simple circuit to do this.

            Kind regards,
            CB
            DashPC - The Linux Car (since 1999).

            Dash LCD, Via Epia, GPS, XM, OBDII, DSSC Shutdown Controller.

            As seen in the book Geek My Ride

            Comment


            • #7
              Ok, here's what I found via google:

              http://www.uoguelph.ca/~antoon/circ/monovib.htm

              You change the delay time by multiplying R1 and C1.

              Kind regards,
              CB
              DashPC - The Linux Car (since 1999).

              Dash LCD, Via Epia, GPS, XM, OBDII, DSSC Shutdown Controller.

              As seen in the book Geek My Ride

              Comment


              • #8
                Edit:

                You'd probably be wise to clean up the input supply at 5-15v by putting the vehicle power through a 7805.

                Also, you'd have to add a simple transistor inline between the pin 3 output and the relay, because the 555 can't source enough current to power a decent relay.

                Finally, you _might_ need to debounce the switch to prevent false triggers. I experienced that only one time though, using the circuit I described (it was a long time ago ~1997). If you power the circuit from an ACCessory line (I would assume), the worst case scenario would be a 20 (or whatever) second rear-view camera view.

                Have fun!
                -CB
                DashPC - The Linux Car (since 1999).

                Dash LCD, Via Epia, GPS, XM, OBDII, DSSC Shutdown Controller.

                As seen in the book Geek My Ride

                Comment

                Working...
                X