How to use a dc motor to control blinds at different light intensity?

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How to use a dc motor to control blinds at different light intensity?

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An analogue input reading a light dependant resistor the value of which controls a motor shield to move the blinds.

What have you tried ?

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What have you tried so far?

I'd think a servo or stepper would be better, probably difficult to position a dc motor accurately.

But you go first.....

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Yes i have tried. Do i map the ldr values to the motor?

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mdfaheem:
Yes i have tried. Do i map the ldr values to the motor?

As often the case, my suggestion is to think through what you do manually....

If it's very bright, almost closed; not quite so bright, open a bit more; very dull, fully open etc.

But the actual control of the blinds depends on how the motor connects to the blinds. If you have a servo for example, with some kind of coat-hanger-wire-linkage then perhaps the servo's pos is 0 when it's very bright, 90 for medium and 180 for very dull.

You can't ask questions like "Do i map the ldr values to the motor?" without giving more detail

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I'd think a servo or stepper would be better, probably difficult to position a dc motor accurately.

I agree wholeheartedly but the OP asked about using a dc motor.

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UKHeliBob:

I'd think a servo or stepper would be better, probably difficult to position a dc motor accurately.

I agree wholeheartedly but the OP asked about using a dc motor.

Exactly, which is very likely to make this an XY problem and involve loads of forum-man-hours to help with with the wrong solution. So I thought it better to suggest what might be a better solution out of the blocks. (Unless of course there's a constraint on the OP's solution such as a client requirement or a wish to re-purpose existing components in the interests of economy.)

Or or it might just be a loose use of the phrase "dc motor", since steppers and servos are actually motors that run on dc, although not usually styled "dc motors".

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There is also the question of what type of blinds. Even in my limited experience:

  • Roller blinds have a single control to raise/lower.
    Louvre blinds have two controls : rotate and slide.

These may help with the typr of motor.

Then you will get the light source question. How much dark or light will trigger a change, Clouds, cars. etc will make a difference.

Maybe use a sunrise/sunset algorithm or hookup to a sunrise, sunset times website.

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Thank you very much for your replies. I have some idea on how to program.

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This (or a similar project) was done by make:.

Hope this helps.

Robby
noob_at_arduino