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I've been developing an interest for electronics and whenever I have free time I like to study it and tinker with whatever components I have at home.

An interest in electronics + the annoyance of having to open / close my blinds every single day led me to want to automate this!

My blinds are manual - to open close I need to pull a cord.

I apologize in advance by my lack of knowledge, but I'm here to get some advice / feedback.

Rough sketch of my idea

Would my below circuit work in theory? Am I missing something - aka, is it gonna explode on me? (joking)

Thank you in advance and I apologize if this is not the right place to post!

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  • \$\begingroup\$ Do you want the blinders always to fully open and fully close? This requires limit switches at the beginning and end of travel. Also, what do you mean by "automatic?" A lamp timer opens and closes them? An outdoor brightness sensor opens and closes them? Other? \$\endgroup\$
    – AnalogKid
    Commented Jun 5 at 22:18
  • \$\begingroup\$ @AnalogKid - By automatic, I just meant clicking a button and it fully opens, closes or stays somewhere in between. :) \$\endgroup\$
    – pipocaDourada
    Commented Jun 6 at 7:05

2 Answers 2

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You would require a DPDT switch, two limit switches and two diodes to carry out the following functions:

  1. Initiate 'up' / 'down' movement

  2. Stop the motor at 'end of travel' in either direction

  3. Permit travel in the opposite direction after an 'end-stop'.

Here's the schematic.

enter image description here

A DPDT switch with 'centre off' position would be required to facilitate 'mid-way' stoppage.

The speed could be controlled by varying the motor voltage.

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  • \$\begingroup\$ Thank you for the constructive feedback! For this case you wouldn't recommend a potentiometer? I was considering powering this with a 5V power supply! :) \$\endgroup\$
    – pipocaDourada
    Commented Jun 6 at 7:04
  • \$\begingroup\$ Anytime! The potentiometer is a part of the DC motor speed controller. \$\endgroup\$
    – vu2nan
    Commented Jun 6 at 9:35
  • \$\begingroup\$ I see, thank you! \$\endgroup\$
    – pipocaDourada
    Commented Jun 6 at 13:38
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The circuit would not work as drawn. The 3p switch (you actually need a DPDT switch) must be connected across both ends of the motor to control direction. The potentiometer speed control is extremely inefficient and will require heatsinking on the transistor to keep from destroying it. Limit switches or some other way to tell the motor to stop are useful to prevent damaging your shades and/or motor. The DC motor will likely require a gearbox.

If you are just looking for a retrofit solution, there are remote control kits available for ~$100 that I can attest from experience work very well.

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  • \$\begingroup\$ thanks for the feedback! For the potentiometer, would you suggest the same as vu2nan is recommending? To control the spped by varying the motor voltage? \$\endgroup\$
    – pipocaDourada
    Commented Jun 6 at 7:08
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    \$\begingroup\$ Yes, but how you control the motor voltage is the hard part. Though for a shade, I'm not sure there's enough benefit in controlling the speed of the motor to make it worth your while. \$\endgroup\$
    – vir
    Commented Jun 6 at 15:32

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