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Offline dsesmgTopic starter

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DC motor
« on: August 07, 2009, 01:39:17 AM »
I need to ask a very basic question for switching a DC motor.
I am trying to turn on a DC motor when I push a microswitch.
I will push a microswitch when the motor is in contact with power supply.
I prepared a picture. Please take a look
http://www.flickr.com/photos/34955071@N02/3796873111/sizes/o/
The motor will be attached with the microswitch So, the microswitch can be with the motor at any time.
But, the power supply should be seperated from them.
How can I turn on this DC motor by pushing the microswitch(Normal open) while avoiding short circuit?


Offline SmAsH

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Re: DC motor
« Reply #1 on: August 07, 2009, 01:59:09 AM »
the simplest i can see is to have battery+ connected to no and motor+ connected to com...
this will result in the motor spinning while the switch is down...
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Offline dsesmgTopic starter

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Re: DC motor
« Reply #2 on: August 08, 2009, 12:08:37 AM »
It works very well.
Thank you very much.
Have a great day.

Offline SmAsH

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Re: DC motor
« Reply #3 on: August 08, 2009, 12:15:39 AM »
great to hear!
just a note: if you want to reverse the operation (turn when switch not pushed down)
change battery+ to nc and it will go when its not pushed down ;D
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Offline dsesmgTopic starter

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Re: DC motor
« Reply #4 on: August 11, 2009, 09:46:03 AM »
Hi, how are you?
Yes, I just tested and it works very well, too.
Thank you so much for teaching me.
I appreciate that very much. :)

Offline SmAsH

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Re: DC motor
« Reply #5 on: August 11, 2009, 03:54:24 PM »
im always happy to be of help ;D
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Offline dsesmgTopic starter

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Re: DC motor
« Reply #6 on: August 16, 2009, 12:51:56 AM »
hi,  how are you?
This is the current method I used to turn on and off a motor. http://www.flickr.com/photos/34955071@N02/3811240545/sizes/o/in/photostream/
And, right now, I am trying to test a photo transistor like this one http://www.eleparts.co.kr/epdf/SENSOR/ST-3811.pdf) and an infrared emitter like this onehttp://www.eleparts.co.kr/epdf/SENSOR/EL-1KL3.pdf
I need to use this photo transistor as a switch, and this emitter as the swtich's trigger wire so that I could turn on and off the motor.http://www.flickr.com/photos/34955071@N02/3813222826/sizes/o/
Could you please advise me how to achieve this?
I've tried to search for information about this but I am lost. :-[

Offline SmAsH

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Re: DC motor
« Reply #7 on: August 16, 2009, 01:18:00 AM »
the last link is to a servo, why is this?
the photo attached is the general setup of how it works.
it works just like any other transistor except the base is now the amount of light.
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Offline dsesmgTopic starter

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Re: DC motor
« Reply #8 on: August 16, 2009, 01:43:02 AM »
Hi, James, Thanks a lot.
I just tested with the schematics.
The motor doesn't start. I tested in a complete darkness but it is the same.
oh.. by the way, the motor I am using is a DC geared motor. It is just in a servo housing.

Offline SmAsH

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Re: DC motor
« Reply #9 on: August 16, 2009, 01:50:08 AM »
first off, have you tried with the transistor in backwards? it may be backward...
and for the wavelengths of both, the transistor is rated for 700-1000nm, what is the emitter rated for?
i cant get its datasheet to load on my pc...
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Offline dsesmgTopic starter

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Re: DC motor
« Reply #10 on: August 16, 2009, 02:18:22 AM »
Yes, I tried to reverse the transistor.
oh.. sorry for the link. You can see the data sheet of the emitter from here.
http://www.eleparts.co.kr/epdf/SENSOR/EL-1KL3.pdf

Offline SmAsH

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Re: DC motor
« Reply #11 on: August 16, 2009, 02:24:19 AM »
i cant see it :-\ can you upload screenshots of the pages for me?
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Offline dsesmgTopic starter

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Offline SmAsH

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Re: DC motor
« Reply #13 on: August 16, 2009, 02:51:24 AM »
nope, those work...
i don't think its a problem with the wavelength... its at 940nm...
have you made sure the ir led is working?
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Offline dsesmgTopic starter

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Re: DC motor
« Reply #14 on: August 16, 2009, 03:02:06 AM »
no.. actually, what i did with your schematics is, I made a circuit and I shed some light on the transistor to see how it's reacting. Please correct me if I am wrong.
On emitter side, I didn't do anything yet. :-[
Could you advise me how the emitter should be wired?

Offline SmAsH

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Re: DC motor
« Reply #15 on: August 16, 2009, 03:05:37 AM »
well, the emitter chews up 1.35V@100mA...
so, depending on your supply voltage.. you should work up a resistor and try it up..
this is probably why the circuit hasn't been working ;)
the transistor requires a certain wavelength to operate.
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Offline dsesmgTopic starter

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Re: DC motor
« Reply #16 on: August 16, 2009, 03:18:11 AM »
I see, then, I will contact the supplier and ask for some help.
When I do it, I will post some result.
Thanks a lot, James.

Offline SmAsH

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Re: DC motor
« Reply #17 on: August 16, 2009, 03:22:41 AM »
why do you need to contact the supplier? do you have the led yet?
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Offline dsesmgTopic starter

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Re: DC motor
« Reply #18 on: August 16, 2009, 04:03:36 AM »
no, I have the sensors right now.
I thought I need to ask for some information on how much resistance needs for this transistor to work.
I just tested with 10k ohm and 100k ohm but it doesn't seem to work, so...

Offline SmAsH

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Re: DC motor
« Reply #19 on: August 16, 2009, 04:13:53 AM »
you need the led for the transistor to work!
the resistor is for the led!
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Offline dsesmgTopic starter

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Re: DC motor
« Reply #20 on: August 16, 2009, 04:20:09 AM »
Please correct me if I am off from your point.
So, I put LED on the positive side of the transistor and I put resistors on the positive side of LED?
I am sorry. I am very new with electrics.

Offline SmAsH

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Re: DC motor
« Reply #21 on: August 16, 2009, 04:32:04 AM »
the led and transistor can be different circuits completely.
the leds light is what activates the transistors "switch".
without light in the right wavelength the transistor will not function.
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Offline dsesmgTopic starter

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Re: DC motor
« Reply #22 on: August 16, 2009, 04:51:01 AM »
I see. then, Could you advise me how to make a circuit for the LED to switch the transistor?

Offline SmAsH

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Re: DC motor
« Reply #23 on: August 16, 2009, 05:09:08 AM »
yes, its treated like any other led circuit.
+battery--resistor--(led+ led-)--battery-
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Offline Soeren

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Re: DC motor
« Reply #24 on: August 16, 2009, 12:11:21 PM »
Hi,

You can't drive your motor directly from the photo transistor!
It simply hasn't got enough power handling for this, so you need to use the photo transistor for driving another transistor which can.
When you have the right setup, you can use a flash lamp, a desktop lamp, sunshine, the LED or whatever to turn it on.
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Please remember...
Engineering is based on numbers - not adjectives

Offline dsesmgTopic starter

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Re: DC motor
« Reply #25 on: August 17, 2009, 09:00:18 AM »
Could you advise me how to set up the transistors correctly?

Offline dsesmgTopic starter

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Re: DC motor
« Reply #26 on: August 21, 2009, 07:10:08 AM »
Hi, I've been thinking of how to turn on and off 5VDC geared motor using a photo transistor I have.
http://www.eleparts.co.kr/epdf/SENSOR/ST-3811.pdf
http://www.flickr.com/photos/34955071@N02/3813222826/sizes/o/
The motor looks like a servo, but it is not a servo. Just a geared motor in a servo housing for better installation. :)
So, I am thinking of arranging the circuit like this to turn on and off the motor using the photo transistor.
http://www.flickr.com/photos/34955071@N02/3842705484/sizes/l/
Could you advise me whether this circuit is ok?

Offline SmAsH

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Re: DC motor
« Reply #27 on: August 21, 2009, 07:17:17 AM »
im not too familiar with the tip102 but wouldn't a low signal at base turn it off?
if it works like i think it does, look at my attached version and try that.
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Offline Trumpkin

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Re: DC motor
« Reply #28 on: August 21, 2009, 02:16:19 PM »
Quote
im not too familiar with the tip102 but wouldn't a low signal at base turn it off?
That is correct. It is an NPN Transistor therefore a low signal would turn it off.
Robots are awesome!

Offline SmAsH

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Re: DC motor
« Reply #29 on: August 21, 2009, 05:00:25 PM »
i think i might've used it once before on a small blinking led project i found on instructables ;D
i knew it was npn from the symbol, but i just wasnt sure because of the way dsesmg had it drawn.
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