Need help to draw and design circuit.

[Christopher Jackson]

Hi everyone

Please can someone out there help me to draw a working circuit for the following concept:

I want to build a unit that can open and close peoples blinds as soon as the sun comes up. I know there are units out there, but my country is so far behind and I do not feel like making a mission to import these units as it will take too long and too much money and red tape. The switches (light activated) ones we have here are only 12VDC.

* 1 x light activated switch.
* 2 x electric motors both at 12VDC input. (2nd motor must only kick in after first one has completed it's duty, pully is linked onto a micro switch to deactivate motor number 1)
* 2 x microswitches (to open circuit so power is switched off)

A light activated switch that has a 12VDC input, but 24VDC output that must be downsized to 12VDC again to power up a 12VDC electric motor. Power input is 240VAC @ 50A.

 

[davenn]

A light activated switch that has a 12VDC input, but 24VDC output that must be downsized to 12VDC again to power up a 12VDC electric motor.

that really doesn't make sense ... where is the 24V coming from ?

 

[Martaine2005]

A light activated switch that has a 12Vdc input, but 24Vdc output that must be downsized to 12Vdc again to power up a 12Vdc electric motor.

Why can't the 12v input from the light activated switch power the 12v motor?

Martin

 

[Martaine2005]

@davenn was faster on the keyboard as usual..

Martin

 

[Old Steve]

Why two motors? That over-complicates things. Can't you just use one motor and run it in one direction to open the blinds, the other direction to close them? A DPDT relay, (or electronic H-bridge driver), could reverse the polarity of the motor connections to do this. The light-activated switch could then select direction at the same time that it powers the motor to open or close the blinds. As you say, a limit microswitch at each end of travel could inform your circuit that the blinds are fully open/fully closed.

And as mentioned, why would you want a light-activated switch that has a 12VDC input and 24VDC output, that must then be stepped back down to 12VDC before it's useful?
(One could be built - a 12VDC light-activated switch which feeds a 12VDC to 24VDC DC-DC converter, but why? Do you need 24VDC somewhere else in your circuit?)

A small circuit board would most likely need to be assembled for this project, with a 12VDC regulator and logic to control the operation. You're equipped to do this?
Assuming you are, you could even make the light-operated switch yourself, out of very few components. A quick Google will produce plenty of suitable circuits.

Don't forget that you may need a geared DC motor, or electronic motor-speed-control, if you want to avoid external gearing. That's pretty easy to impement on the circuit board.

Out of interest, do you plan to go into production and sell these units, or is it a 'one-off', just for yourself.