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HB-25 Motor Controller — Parallax Forums

HB-25 Motor Controller

bdrew7bdrew7 Posts: 38
edited 2008-02-03 03:18 in Robotics
Does anyone know how to exert a hardware reset to the HB-25 motor controller?

Thanks.
Bernard

Comments

  • DgswanerDgswaner Posts: 795
    edited 2008-02-01 04:54
    put a switch inline with the power to the electronics part of the HB-25. just a manual switch would work or something like a relay.

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    "A complex design is the sign of an inferior designer." - Jamie Hyneman, Myth Buster

    DGSwaner
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2008-02-01 16:51
    Bernard,

    What is it you’re trying to accomplish in a hardware reset? Is your HB-25 becoming unresponsive?

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    Chris Savage
    Parallax Tech Support
  • bdrew7bdrew7 Posts: 38
    edited 2008-02-01 18:16
    The application is an autonomous solar powered electric boat that will try to navigate from Northern Portugal to Tybee Island, Georgia.·

    The watch dog timer for the control system for the boat must be able to reset all control components, such as the servo controller, gps, cpu, etc.

    I have found that if the cpu and the HB-25 come up in a random sequence, the HB-25 is unresponsive.· I need to have everything reset in a known manner.

    Thanks.
    Bernard
  • ZootZoot Posts: 2,227
    edited 2008-02-01 19:18
    If the peripheral you want to reset does not have a "soft" reset pin, you could use voltage regulators with "on/off" control pins -- essentially this lets you control power on/off to peripherals with a microcontroller (host) pin (or pins). So you could have the micro power down and then power up the HB, power down then power up the GPS, etc. in whatever order you want and with whatever delays you want in between.

    An example would be the Sharp PQ05RD21 (5v), PQ09RD21 (9v), PQ12RD21 (12v). There is also 3.3v version. These are TO-220 packages with 4 pins.

    These are available for about US$1.95 at Digikey.com. You could do it slightly cheaper with transistors for supplying an on/off 5v supply to peripherals, but the above have an advantage in that your part count is very very low and the regulators will supply up to 2A each, so you would only need one for each SET of peripherals that needs to powered up in some kind of sequence. Plus they have current/thermal limiting and shutdown, so your boat won't melt if there is a problem and the regulators will keep trying to bring themselves back online without frying.

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    When the going gets weird, the weird turn pro. -- HST

    1uffakind.com/robots/povBitMapBuilder.php
    1uffakind.com/robots/resistorLadder.php
  • ZootZoot Posts: 2,227
    edited 2008-02-01 19:23
    Wait, shoot, that will be fine for other peripherals -- I forgot that the HB-25 has on-board 5v regulator powered from the motor Vin supply... you could use the 12v version above (in parallel with diodes if you need more amps) to control the power to the Vin on the motor controller, but for that purpose you might just want to use Solid-State-Relay to turn on/off Vin power the HB-25. That would still give you solid-state solution without a heavy cost or part count (you should be able to pick up an appropriate SSR in the $10-$15 range -- depends on the voltage and amp requirements of your motor supply).

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    When the going gets weird, the weird turn pro. -- HST

    1uffakind.com/robots/povBitMapBuilder.php
    1uffakind.com/robots/resistorLadder.php
  • DgswanerDgswaner Posts: 795
    edited 2008-02-01 21:43
    The HB-25 can't even be powered up at the same time as your processor, they require start up time before receiving a signal. I was looking at SSR's today, I found some DIP-8 IC's that are 2 channel with NC and NO pins so it would be really easy to just cut power to the HB-25s for a second or two via a micro processor. that's what I'm planning for my Web controlled bot, no point in being web enabled is you need someone to flip a switch for you.

    here is a prefab product... 1 channel tho. http://www.hvwtech.com/products_view.asp?ProductID=632

    I looked at the IC they use and that's how I found the 2 channel IC on mouser.

    I'm going to be working on a PCB layout for this over the weekend.


    added: make sure you have a visible return address and perhaps some postage in case it gets lost and ends up some where else... (joke) sounds like a fun project.

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    "A complex design is the sign of an inferior designer." - Jamie Hyneman, Myth Buster

    DGSwaner

    Post Edited (Dgswaner) : 2/1/2008 10:01:14 PM GMT
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2008-02-01 22:19
    It is recommended to have the controller powered up before the HB-25. The I/O line controlling the HB-25 should be LOW very quickly after the HB-25 is powered up.

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    Chris Savage
    Parallax Tech Support
  • bdrew7bdrew7 Posts: 38
    edited 2008-02-02 00:28
    Thanks everyone.·

    I think I will go with a ttl input compatible ssr rated at the needed 25 amps.

    Will have a webpage with a location map of the 3 meter boat as it makes it's way across the Atlantic.· Will have an Orbcomm transpoinder on board for communications·

    Hope all this works underwater??!!
  • DgswanerDgswaner Posts: 795
    edited 2008-02-03 03:18
    let us know when you set sail, it would be really fun to watch the progress.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    "A complex design is the sign of an inferior designer." - Jamie Hyneman, Myth Buster

    DGSwaner
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