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control plus power over 2 wires — Parallax Forums

control plus power over 2 wires

JomsJoms Posts: 279
edited 2009-04-07 20:41 in General Discussion
Have a project I have been thinking about and wonder if there is a chip out there already that can do what I need it to.· I do know that the stamp would work for this, but I would need·7 stamps for a very simple project and it would get a little spendy. (6 for motors, 1 for controller)

Here is what I am trying to do...

I have a 2 conductor sheilded wire that uses an 3pin XLR style connector.· (5v+ or 12v+, data, gnd)· I have 6 motors that are all spaced a ways apart and only connected via the 2 conductor wire.· I need to control the direction of each motor independantly (basically 2 relays by each motor, up or down, if no relay is active, then the motor is off).

Each motor does have 120 available for a local power supply, however size is a problem.· I am trying to fit the circuit I am building and the two relays in a box that is 2" x 2" x 4".


I would be ok using a stamp for the main controller, but just wondering if there is a simple way to control the two relays over one wire.· Actually it would be like 12 channels, 2 for each motor.

If you have any ideas of a circuit that does that or what I should be looking at please let me know.· I was looking at serial control to a basic stamp, but putting a stamp by each motor is kind of over-kill...

Thanks in advance...

Comments

  • Mike GreenMike Green Posts: 23,101
    edited 2009-04-06 20:07
    How about 1-Wire? Dallas Semiconductor has several addressable switches that can drive a switching transistor which could then drive a relay. You'd have to use a BS2p/pe/px Stamp since the others don't have 1-Wire drive capability. The DS2413 (www.maxim-ic.com/quick_view2.cfm/qv_pk/4588) has two addressable outputs and can sink 20mA
  • JomsJoms Posts: 279
    edited 2009-04-07 20:11
    GREAT!!!· This is what I was looking for...

    Question - Does this use the I2COUT command?· The I2COUT command looks like it uses 2 wires?· Is there a different command I should be looking for?

    Thanks!
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2009-04-07 20:14
    Yes. Look at OWOUT and OWIN.

    -Phil
  • JomsJoms Posts: 279
    edited 2009-04-07 20:41
    GREAT! This looks like the command I need. I read through the command in the Syntax Guide and it brought up another question.

    If this is the command to use...

    OWOUT 0, 5, [noparse][[/noparse]bitOne, bitTwo]

    Then where do I put the ROM number that comes addressed to each chip? I see near the bottom of the syntax explaination it shows commands like Read ROM, Match ROM, Skip ROM, Search ROM. I understand what these do, I think, but I don't understand how to put them into the command to send out.

    The way I understand this is that I send the chip ROM number (which according to the data sheet is stamped on the chip), followed by the two bits that I want to output to the two I/O pins on the chip. What am I missing here?

    Thanks again for all the help!
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