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Darlington Array to BS2 — Parallax Forums

Darlington Array to BS2

DonNohioDonNohio Posts: 24
edited 2015-02-14 14:04 in BASIC Stamp
I am thinking of using a 2004 Array output connected to the BS2 input pins using current limiting resistors. The input to the array would be connected to a Digitrax block detector output. The output voltage of the detector is 5v. I would be using current limiting resistors here too. The reason would be to isolate the BS2 from the block detector. Has anyone done this in another form, or see a problem ? I would like to integrate a Stamp into my model railroad for some animation.

Comments

  • stamptrolstamptrol Posts: 1,731
    edited 2015-02-12 05:24
    Hi Don,

    You've got the right idea for both the inputs and outputs. Each Darlington input would only draw a fraction of the 20mA available from a typical Stamp output.

    The only thing to check for reliable operation is that the ground for the block detector and the Stamp are tied together. Same with the loads the Darlington's are driving.

    Cheers,
  • DonNohioDonNohio Posts: 24
    edited 2015-02-12 08:05
    Good point on Grounding to all who may be reading this. It is common practice to have ALL grounds tied together. This minimizes erratic behavior and ambient noise.
  • $WMc%$WMc% Posts: 1,884
    edited 2015-02-14 11:00
    only tie them at one point (ground)
    '
    More then one will cause ground loops
  • DonNohioDonNohio Posts: 24
    edited 2015-02-14 14:04
    I have ran to a polarity conflict connecting the outs of the Array to the BS2. After again checking the schematic and data sheet on the Block Detector the LED output is already isolated and has 4.5vDC output. Also current limiting resistors. This is good in the fact that it eliminates some circuitry and hardware. A few less things to go wrong. The BS2 has survived a test run :)
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