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

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

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

What have you tried ?

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.....

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

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

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.

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".

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.

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

This (or a similar project) was done by make:. https://www.youtube.com/watch?v=YcR2yHHYzd8 http://makezine.com/projects/mini-blind-minder/

Hope this helps.

Robby noob_at_arduino