DC motor

[dsesmg]

Hi, thanks a lot.
I just tested with the circuit you proposed and it works great.
when I exposed the photo transistor to the sunlight, the motor spins.
Also, when i beam TV remote control light to the photo transistor, the motor spins a little.
I think it is because, the TV remote control doesn't beam the light continuosly even if I keep the button pressed.
I hope i could make a circuit for the infrared emitter and test with this photo transistor circuit.
As you know, the current emitter i have is this specification.
http://www.flickr.com/photos/34955071@N02/3825092211/sizes/o/
http://www.flickr.com/photos/34955071@N02/3825079541/sizes/o/
http://www.flickr.com/photos/34955071@N02/3825092215/sizes/o/
http://www.flickr.com/photos/34955071@N02/3825079427/sizes/o/
But, I have little knowledge about this.
I need to control this emitter by using some microcontroller signal.
Could you advise me how to wire up the emitter?

[SmAsH]

wait, what do you want to control?
the current flow from the collector to emitter?
there you will put the base to a digital pin... am i getting you?

[dsesmg]

Hi, James,
Yes, I need to control the current flowing from the collector to emitter so that I can control the on/off mode of the emitter.
Yes, I will put a digital pin to the base of the TIP102 so that the TIP102 transistor could act like a switch.

[dsesmg]

is this circuit OK?
http://www.flickr.com/photos/34955071@N02/3845028272/sizes/l/

[SmAsH]

yeah, that will work...
just a word, you don't need the diode if you are controlling something like an led...
the diode is just to stop back emf from motors or other coils.

[dsesmg]

Thanks a lot, James.
OK, I will take out the 1N4004.
I will test with this circuit and I will get back with the result.

[SmAsH]

ok, your testing it with a microcontroller right?

[Soeren]

Hi,

yeah, that will work...

... If a LED with internal current limiting is used, yes, otherwise, just for a split second

[SmAsH]

why is that, because of no resistor?

[Soeren]

Yes.

[dsesmg]

Hi, yes,I am using it with a microcontroller.
then, how much ohm resistor do I need to use?
Because, I tested with the circuit after taking out 1N4004 from the circuit.
The emitter doesn't show any result.
So, I replaced the emitter with a normal LED. The LED blinked well so I brought it close to the transistor and the motor spinned very well.
I thought the emitter is broken or something.
Could you advise me how much ohm do I need to use and where should it be connected?

Also,the photo transistor only responded to red colored LED.
I have red,green, yellow LEDs and tested with them all.
Anyway, only the red colored LED is giving effect on the photo transistor.

[SmAsH]

well, if you are giving the led 5v as your supply i would say something in the 150-250 ohm region would work well.
the resistor should just be placed in between the led +(anode) and your supply.

the reason it only reacts to certain leds is because of its operating wavelengths...
it will only turn on with wavelengths from a certain range. the leds that work must be in that range

[dsesmg]

Thanks a lot, James.
Then, I will test it with 150~250 ohm resistors.
I don't have them right now, so I will order them today.
By the way, I am trying to find better emitter and detector.
Below is the emitters.
* S13317-H
http://www.flickr.com/photos/34955071@N02/3847545598/sizes/o/
http://www.flickr.com/photos/34955071@N02/3846755227/sizes/o/
http://www.flickr.com/photos/34955071@N02/3846755305/sizes/o/

* EL-1CL3
http://www.eleparts.co.kr/epdf/SENSOR/EL-1CL3.pdf

And below is the detectors.
* SP-1CL3
http://www.eleparts.co.kr/epdf/SENSOR/SP-1CL3.pdf
* ST-1CL3H
http://www.eleparts.co.kr/epdf/SENSOR/ST-1CL3H.pdf

I am trying to choose one of those emitters and detectors.
I don't quite familiar with the specification of such sensors.
Could you advise me which emitter has the longest beaming distance and which detector is less sensitive to the visible light?

[SmAsH]

dude! do you have enough programs open

well, you will want to look for a set that are in the same wavelength...
if you want them not to be too affected by visible light then go for a pair in the infrared spectrum...
i cant really give advice on those ones as i think i have a virus or something thats screwing with my adobe
as far as range goes, try to go for a non-diffused emitter as it is generally brighter...

as for the resistors, they will need to change according to your emitters, use the following formula to choose
a resistor: supply_voltage-led_operating_voltage/led_operating_current_in_amps...
eg 5-2=3, 3/.02=150... resistor =150 ohms.
remember to recalculate accordingly...

[dsesmg]

Thank you, James.
It's very helpful.