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Stamp and Pink Power supply — Parallax Forums

Stamp and Pink Power supply

DgswanerDgswaner Posts: 795
edited 2007-07-22 06:09 in General Discussion
I'm trying to find a suitable power supply for a pink, OEM BS2, RF module and a few led's.

The PINK draws 5V @500mA
The BS2-IC consumes 8 mA (guessing the oem BS2 is 24mA)
the RF module is 10 mA
and about 30 mA for the LED's

so round that to 610 +/-

I'd like to use the a 7805 voltage regulator because I have a some on hand and it's a quick and easy circuit.

I know I'll need to have a heat sink on the 7805 and I can draw about 1A from. but I just want to make sure I'm not forgetting something. Is this circuit going to be too noisy for this application? I don't want to shorten the life of my PINK because of a cheap power supply.

does anyone have a better circuit for this application?

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

Comments

  • PaulPaul Posts: 263
    edited 2007-07-20 19:53
    I'm running a PINK off of a LM7805 regulator attached to a Alum. heat sink. It's about 2" by 2.5" with 0.5" fins on the back. It stays nice and warm. (about 98 - 100 degrees F witout a fan)·
    This is the best trade off I could come up with given I also needed 12VDC regulator also. Both are fed from their own halfwave rectifier at 14VDC ungregulated. With a lower voltage you could use a small heatsink I'm sure.
    ·
  • DgswanerDgswaner Posts: 795
    edited 2007-07-20 20:04
    ok that's good to know. I'm putting this in an enclosure. If it stays that warm I think I'm going to add a fan. I don't want it to heat the whole box.

    Since the bs2 is over kill for this project perhaps I'll add temperature controlled to the fan.

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    A complex design is the sign of an inferior designer. - Jamie Hyneman, Myth Buster
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2007-07-20 23:26
    Dgswaner said...(trimmed)
    The PINK draws 5V @500mA
    The BS2-IC consumes 8 mA (guessing the oem BS2 is 24mA)
    the RF module is 10 mA
    and about 30 mA for the LED's
    I think there may be something wrong with your ammeter.· The PINK draws less < 300mA and I believe we’ve actually tested them at ~250mA.· Unfortunately my meter only has several ranges up to 200mA and then 10A, but even the documentation for the SB70 from NetBurner recommends a power supply capable of at least 350mA. ·
    ·
    As for the BASIC Stamp 2, running it takes ~3mA, although the OEM’s regulator may lose a little more than the Module version. ·Still, 24mA or even 8 seems high.· I almost thing the RFID Reader was higher than what you listed. ·I would have to check it myself.· Take care.

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    Chris Savage
    Parallax Tech Support
  • DgswanerDgswaner Posts: 795
    edited 2007-07-21 01:24
    Well that's even better, I gathered all my info from online data sheets except for the bs2sx oops I mean OEM bs2 , I did no actual testing. even if the RF module is higher than I listed, I looks like I have plenty of mA left over. I'm about to make the power supply so we'll see if it all goes up in smoke or not!

    Thanks for the input.

    added:
    that what's in red

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

    Post Edited (Dgswaner) : 7/22/2007 12:04:54 PM GMT
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2007-07-22 06:09
    I will try to make sure that current draw is covered in the revised documentation (as well as other/future documentation). Take care.

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    Chris Savage
    Parallax Tech Support
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