Want to make a motorized roll down projection screen
I want to build a motorized roll down screen, I know how to do most of it but am wondering the best way to determine when the screen is all the way down to stop the motor, and ideally I would like the motor to slow down during the last few inches for a more precise stop.
The best idea I came up with is to put black bands on the back side of the screen at different distances from the side along with optical sensors, one set of black bands would mean "slow down" and the other set would mean "stop"
I think the optical option is the best (most precise and reliable, no moving parts), but I have no idea how to make circuitry to interpret what the optical sensors see and control the motor based on that.
I would prefer something with only circuits and no programming required and I think this is a simple enough task for this to be possible. What would I need to have the optical sensors control the motor? Basically anything that can convert what the sensors see to an open or closed circuit (making them work like a switch) and I'd be set to do the rest on my own.
Also, I realize this would likely need a basic stamp, but is there anyway to make the circuit respond to a specific remote control signal so that I can trigger it to go up and down with my universal remote? If this is possible with a basic stamp, I don't mind doing the whole thing controlled by a basic stamp if it's not harder or more expensive than with plain circuitry like transistors.
Thanks for any help
The best idea I came up with is to put black bands on the back side of the screen at different distances from the side along with optical sensors, one set of black bands would mean "slow down" and the other set would mean "stop"
I think the optical option is the best (most precise and reliable, no moving parts), but I have no idea how to make circuitry to interpret what the optical sensors see and control the motor based on that.
I would prefer something with only circuits and no programming required and I think this is a simple enough task for this to be possible. What would I need to have the optical sensors control the motor? Basically anything that can convert what the sensors see to an open or closed circuit (making them work like a switch) and I'd be set to do the rest on my own.
Also, I realize this would likely need a basic stamp, but is there anyway to make the circuit respond to a specific remote control signal so that I can trigger it to go up and down with my universal remote? If this is possible with a basic stamp, I don't mind doing the whole thing controlled by a basic stamp if it's not harder or more expensive than with plain circuitry like transistors.
Thanks for any help
Comments
1) up/remote up
2) down/remote down
2) up limit (looks to see if it is fully up)
3) Shaft counter or encoder (counts the pulses on the shaft to see if fully down)
4) motor up relay or you can use this pin to send pulses to the HB-25
5) motor down relay or can use this pin as an lock-out relay to prevent the motor from running when not command to.
Remember that garage door operators use relay logic to control the door. The way it is controlled, it uses an lead screw with nut, which trips the up or down limit switch to stop the door in close or open position. You need ask yourself what features you would like to have and how it is controlled.
I hope this give some idea what you need to do.
About making it respond to a specific remote signal, how would I do that?
Thanks
The HB-25 can control the speed has well and can do forward and reverse with one I/O pin with a 220ohm resistor in series, which protects the I/O pin.
You can get wireless controller kit to input to the Stamp with a pullup resistor and 220ohm series resistor to the I/O pin.
All this info on the internet and if want I can provide schematic if you need one. I am typing this on my phone.