I am trying to create blinds that will respond to a simple up and down toggle switch.
I want them to stop when the blinds reach their destination, and to essentially power off at that point.
My question is which would be the best sensor to use for this project?
I have a habit of over complicating things but want this to be really simple. So for example if the switch is flicked to up then the blinds will do nothing if they are already up, otherwise they will roll up to the marker point then stop. If the switch is flicked to down then the same scenario will occur.
I just can't seem to find the solution for the best type of sensor to use to determine the position and therefore direction to move in.
any help really appreciated
(I honestly have googled this, and spent many hours on youtube and forums)
Limit switches come to mind.
Optical switches (IR) may work if you prefer contactless.
Or a current sensor on the motor, at least when the blinds are up the motor will stall and the current goes up.
Anyway, lots of option, and a picture of your specific blinds would be helpful for suggestions.
The type of blinds i am using are the chord pull roller blinds type.
The motor is a step motor attached to the end of the pully system that slots into the roller blind on one side.
this is the set up so far (minus the actual blind)
I can easily set the max number of motor rotations to potentially stop the blinds rolling too far in either direction but if someone has manually changed the position of the blinds then this would be ineffective.
The intention is that eventually, when I learn how to add things to smart home applications to be able to add this to my Alexa or similar so I am trying to plan ahead and assume that i may not be able to physically see the current position of the blinds to begin with.
Stepper, that's interesting information. So at least the current sensing doesn't work.
You'll need one limit sensor: the fully up position. That's the easiest. You can attach a magnet to the side of the bottom of the blind, and a hall effect sensor (or switch?) next to it. You know after all where that part is going to end up so you can be sure to hit the target. For a sensor at the bottom, not so much.
Then upon start-up of your Arduino, make sure the blind is fully up. I.e. if you don't sense the magnet, start moving the blind up until you do. From there you can work with the stepper (assuming it's strong enough so you won't lose steps along the way).
Move it down - based on number of steps. Move it up - based on number of steps - and there double check with the sensor. Move it halfway, and positions from there - again simply based on the number of steps.
That makes so much more sense than the weird and wonderful idea's I was considering, all of which were far to complex and overkill for the project.
I am using the stepper motor simply because I have some kicking around and want to put them to use. The blinds are only about a meter long and light weight so I think (hope) it will be ok
