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Using sensor to program motor

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Katanahikari

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I have a motor on a dbdt switch that rotates a scroll of paper continuously. Is there some way I can design it that the paper automatically stops scrolling at predetermined points, and then resumes when the switch is reset. Some combination of sensors? Is it possible to do without arduino?
 

ClydeCrashKop

Well-Known Member
Most Helpful Member
If it can run for a period of time, a 555 timer IC can do it.

If you want one revolution of the scroll, a microswitch and a detent will do it.

If you want a number of revolutions of the scroll, a counter IC + a few more chips will do it.
 

Les Jones

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Most Helpful Member
If the paper is light in colour you could use a reflective opto sensor such as this and put a black mark on the paper where you wanted it to stop. If the paper was dark in colour you could stick on a reflective marker wher wou want it to stop. An alternative would be to yse a slotted opto sensor and punch a hole at the edge of the paper where you want it to stop. You would arrange the output of the sensor to drive the motor when it was not at a marked point and stop the motor at the marked point. To restart the motor you would overide the sensor to start the motor. One it had moved away from the mark the button could be released. Posting some pictures and more information on the device may help members to come up with other suggestions

Les.
 
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Katanahikari

New Member
What would the circuit look like on a breadboard if I used the reflective or slotted sensors? It's a 3v dc motor. Pics not available yet cuz I'm still in planning phase

If the paper is light in colour you could use a reflective opto sensor such as this and put a black mark on the paper where you wanted it to stop. If the paper was dark in colour you could stick on a reflective marker wher wou want it to stop. An alternative would be to yse a slotted opto sensor and punch a hole at the edge of the paper where you want it to stop. You would arrange the output of the sensor to drive the motor when it was not at a marked point and stop the motor at the marked point. To restart the motor you would overide the sensor to start the motor. One it had moved away from the mark the button could be released. Posting some pictures and more information on the device may help members to come up with other suggestions

Les.
 

Les Jones

Well-Known Member
Most Helpful Member
Something like this should do what you want. The values should suit the reflective sensor RPR-220 in the link I posted. (RPR-220 data sheet) You will have to choose a suitable mosfet and diode to suit the current taken by your motor. It must be a logic level mosfet so it turns fully on with 5 volts on the gate. Adjust the potentiometer to a voltage half way between the output of the photo sensor when the black mark is in front of it and when the mark is not in front of it. If you use a slotted sensor you will need to swap over the inverting and non inverting inputs on the comparitor.

Photo sensor.jpg
I have just noticed that I have not drawn a decoupling capacitor across the supply lines. Add a 100 uF 16V capacitor across the supply lines. (This is in addition to the 100 nF capacitor close to the power pins on the LM393.)

Les.
 
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