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How to Configure Phototransistor circuit to act as a small motor on/off switch

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jemanthe

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Can some one please tell me how to create the following circuit. My goal is to use an IR phototransistor as an on off switch for small motor.

I would like to use the following:

· Matched Infrared Emitter and Phototransistor Detector
o 1 x infrared emitter - 2V 40mA
o 1 x phototransistor detector - 20V 25mA
o **broken link removed** /index.jsp?productId=2049723

· 1.5-3V DC Metal Gear Motor
o 0.18-0.25A no load
o 0.70A max efficiency
o 1.5-3VDC Metal Gear Motor - RadioShack.com

· 1.5 V Battery

o 1.5V sufficient??????
o Do I need to use 3V-?????

· Resistor

o Type- ????
o Resistance- ?????

I am not sure what configuration to wire this in. Any suggestion would be greatly appreciated!!!!

Thanks in Advance,

Jon
 
Will the motor always turn in one direction?
Are you trying to use the IR emitter and detector to create a beam-break detector (Photo interrupter)?
 
Hi Mike,

I only need the motor to turn in one direction.

I am not try to create a beam break detector.

I need the motor to turn on when the emitter is detected by the phototransistor.

Thanks,

Jon
 
...
I am not try to create a beam break detector.

I need the motor to turn on when the emitter is detected by the phototransistor.

Thanks,

Jon

Ok, so you want a NOT(beam break detector):D

I recommend one of these, followed by a NPN transistor to drive the motor
 
Will the motor always turn in one direction?
Are you trying to use the IR emitter and detector to create a beam-break detector (Photo interrupter)?

Thanks for the suggestion. I am just not quite sure what it does and how to use it?
 
Think of it as a switch that is closed when nothing is inserted in the slot. If you put something opaque in the slot, the switch is open. Adding just a couple of parts (two resistor and one transistor) will allow that switch to control your motor.
 

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I am sorry if this if frustrating for you but what you are saying is... basically the IR emitter signal would act to close the switch, via your suggestion (Optical - Photointerrupters - Object Sensor / Slot Type - Transistor Output ), to complete the circuit when detected and the switch would remain open when no signal from the IR emiiter is detected?

Thanks Again,

Jon
 
I am sorry if this if frustrating for you but what you are saying is... basically the IR emitter signal would act to close the switch, via your suggestion (Optical - Photointerrupters - Object Sensor / Slot Type - Transistor Output ), to complete the circuit when detected and the switch would remain open when no signal from the IR emiiter is detected?

By Jove, I think he's got it... Is the physical configuration of the photo-interrupter I referenced ok for your project? Digi Key has others. Note the price, and the availability of the one I referenced. These have much better optical coupling than you will achieve with a separate emitter and detector.
 
By Jove, I think he's got it... Is the physical configuration of the photo-interrupter I referenced ok for your project? Digi Key has others. Note the price, and the availability of the one I referenced. These have much better optical coupling than you will achieve with a separate emitter and detector.

Thanks Again! Your help thus far has been quite enlightning.

I am not sure if this configuration will work as I need the IR emitter to be detected
by the phototransistor at a distance of about 5 feet. The IR emitter as well as phototransistor shall be moblie and constantly coming in and out of range of eachother and when in range I need the motor to turn on and when out of range the motor to turn off. I want to make this as simple as possible. I think I need a simple diagram of the componenets I listed above to start bulilding this thing. Is it possible you could provide this?

Thanks Much,

Jon
 
Bad news! No simple dc-coupled IR LED and IR detector has a range of 5ft, unless it has very complex optics with beamwidths of less than a couple of degrees (making hard to align). The IR detector is usually swamped by ambient radiation from lighting and sunlight.

The only viable way of getting a range of several feet is to use the method used in IR-based remote controls such as on your TV set, where the emitter LED is pulsed on/off at an ultrasonic rate (usually ~40kHz), and the detector is AC-coupled to a narrow-bandwidth, high-gain amplifier tuned to 40kHz.

Good news is that the detector is available as an cheap IC. Read this thread; it talks about how to build the transmitter.
 
Bad news! No simple dc-coupled IR LED and IR detector has a range of 5ft, unless it has very complex optics with beamwidths of less than a couple of degrees (making hard to align). The IR detector is usually swamped by ambient radiation from lighting and sunlight.

The only viable way of getting a range of several feet is to use the method used in IR-based remote controls such as on your TV set, where the emitter LED is pulsed on/off at an ultrasonic rate (usually ~40kHz), and the detector is AC-coupled to a narrow-bandwidth, high-gain amplifier tuned to 40kHz.

Good news is that the detector is available as an cheap IC. Read this thread; it talks about how to build the transmitter.

Cannot Thank You enough for all the guidance. I guess I am at a dead end here but will try via another route starting with your suggestions!!

Thanks Again Mike,

Jon
 
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