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Minimum Circuit for BS2? — Parallax Forums

Minimum Circuit for BS2?

HandtoolHandtool Posts: 17
edited 2009-01-29 21:02 in BASIC Stamp
Hello,

I am working on a school project.· I've built and debugged my circiuts and code using a Board of Education.· I'm now in the process of building my own PCB to fit in·a specific·enclosure.· I am planning to program the stamp with the BOE and transfer it to a header on the custom board.··Please take a look at the attached schematic.· Will it work in this manner or is something else nescessary?

Thanks,

Dusty
SimSchematic.gif
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Comments

  • metron9metron9 Posts: 1,100
    edited 2009-01-28 21:22
    I did not look up the specs on the bluetooth but you may want to check if the stamp has enough power to run it. I assume it does but if not, a separate 5V regulator may be needed.

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  • UghaUgha Posts: 543
    edited 2009-01-28 21:42
    Your going to need a flyback diode on your motor... You also shouldn't run it off VDD if it can be avoided. Its unlikely the stamp's regulator can put out enough current for it without
    frying it.

    Where's the 5v coming from? a regulated source or just a battery? Its best not to tax the BS2's regulator too much.

    Like Metron9, I don't know much about the bluetooth module, but you need to find out what its peak current consumption is and compare it to what the stamp's regulator can put out.
  • Bill ChennaultBill Chennault Posts: 1,198
    edited 2009-01-28 22:56
    Handtool and metron0 and Ugha--

    I run an eb501 off VDD quiet successfully. However, I provide VIN with 12 volts. It appears Handtool is powering VIN with 5 volts and taking 5 volts off VDD. I did not know that was possible. However, I am certainly not an expert.

    --Bill

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  • ercoerco Posts: 20,263
    edited 2009-01-29 00:15
    You may need to drop your transistor bias resistor from 1K to 330 or 220 ohms.· Use the highest resistor value that fully saturates your transistor switch.

    And depending on your speaker/transducer type, you may have to change your circuit. A regular speaker will need a series·electrolytic cap (per typical manual info); a·driven piezo element may need a parallel resistor to drain the residual charge. But if it's a piezo beeper that takes a steady +5 volts, you're all set.

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  • UghaUgha Posts: 543
    edited 2009-01-29 01:51
    Bill Chennault: That's why I was asking where he's getting his +5v [noparse]:)[/noparse]

    Handtool: The onboard regulator on the BS2 will reduce your 5volt to lower than 5v coming out of VDD.

    If your 5volt input is regulated and completely clean, you can feed that right into
    VDD with nothing connected to VIN and it should run fine.
  • HandtoolHandtool Posts: 17
    edited 2009-01-29 02:23
    Thanks for the input fellas.· I did some research on how the BOE is setup.· Please take a look at this updated schematic.
    SimSchematic1.gif
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  • ZootZoot Posts: 2,227
    edited 2009-01-29 17:59
    You still don't have a diode on your motor. Also, if you are using a separate regulated power supply as your schem. shows, then I would remove the Vin connection to the Stamp, and run Vdd from your outboard regulator to Vdd on the Stamp (this bypasses the Stamp's onboard regulator which is a tiny little thing).

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  • Bill ChennaultBill Chennault Posts: 1,198
    edited 2009-01-29 21:02
    Ugha--
    Bill Chennault: That's why I was asking where he's getting his +5v [noparse]:)[/noparse]
    Oh! Thanks!

    --Bill


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