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Schematic to Circuit assistance — Parallax Forums

Schematic to Circuit assistance

flying_flipflying_flip Posts: 36
edited 2009-01-03 03:29 in BASIC Stamp
I am laying up a circuit for the "Maximum LEDs" post.

Please review the attached pictures.
I need confirmation of my translation from Schematic to Circuit board.
I am going to have the boards professional done, so I want to make sure this 2 sections are accurate.

1. Power Supply allows 18 volts to be dropped down to 5 volts.

2. Programming board - Serial cable to Basic Stamp circuit

Thanks,

Phil
Power_Schematic.jpg
203 x 108 - 6K
power_supply.jpg
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Programming_Basic.jpg
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Programming.jpg
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Comments

  • Adrian SchneiderAdrian Schneider Posts: 92
    edited 2008-12-29 08:52
    the programming board isn't right around pin 4/5 of the connector resp. pin 3/4 of the stamp and the capacitors.
    I think, the power supply looks ok. However, you shouldn't really feed it with 18V, rather some 9V or so:
    (18 - 5)V * 150mA = 1.95W power turned into heat vs. 5V * 150mA = 0.75W usable power.

    Isn't that a bit of overkill to produce custom boards for such simple circuits -- unless you intend to produce many of them?

    regards
    adrian
  • flying_flipflying_flip Posts: 36
    edited 2008-12-29 13:31
    How do I fix pins 3,4 of the Stamp?

    I will be using a heat sink on the power supply so that I can use one for this project (2 x 9volts)
    the second for a motorcycle project.

    The 150ma power supply is from a document that was using a transformer power supply.
    I thought if the circuit only needed, say, 55ma thats all it draws.

    If that is not the case, then I need to drop 7 amps down to a usable level as well...

    Thanks,

    Phil

    Post Edited (flying_flip) : 12/29/2008 1:41:07 PM GMT
  • flying_flipflying_flip Posts: 36
    edited 2008-12-29 13:56
    Does this correct the pin 3,4 issue?
    Programming.jpg
    469 x 309 - 23K
  • flying_flipflying_flip Posts: 36
    edited 2008-12-31 22:56
    bump.

    Is the second picture going to handle the Programming component?

    Thanks,

    Phil
  • alphamike27alphamike27 Posts: 10
    edited 2009-01-01 04:37
    It is good practice to place a diode (1N4001 or like) between the input and output of the 7805, with the cathode connected to the input.

    As Adrian has noted, the regulator will get pretty hot with an 18VDC input. You may need to reduce the input voltage if possible, or fit a heat sink to the regulator............................

    Kindest regards

    Alan
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2009-01-02 17:41
    Phil,

    In the future when following up on a thread please post in that thread rather than starting a new one. Anyone trying to refer to your previous work would now have to search for that information.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Chris Savage
    Parallax Engineering
  • flying_flipflying_flip Posts: 36
    edited 2009-01-03 03:29
    Sorry Chris.
    I'm relatively new to forum usage.

    I will try to keep things together [noparse]:)[/noparse]

    Phil
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