Gear pager motor not enough power

Blog entry

By Vansu
2008-11-20 01:40

Okay I am trying to hook up the gear pager motor to test it so I write the code as below:

main:

high portc 3

wait 1

low portc 3

wait 1

goto main

I used the lead to test it and it seem to work the lead turn on and off every second but when I try with the gear pager motor its does not have enough power to move the motor. well the motor move but very slow so its not able to make a sound when it hit something.

Is the location above the correct location?

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By Ant @ Thu, 2008-11-20 02:52

I think the problem may be

I think the problem may be that you are trying to have the Picaxe drive the motor directly, while the Picaxe will be able to drive an LED (about 20ma, but still best to use the darlinton), it just can't supply enouh current to drive a motor, and if you keep trying to drive it that way, the magic smoke might come out.

I would try moving the motor over to one of the darlinting outputs, or use a transister or relay to drive the motor. Let us know how it goes.

By robologist @ Thu, 2008-11-20 07:19

Check some of the sources here

There are posts elsewhere that suggest using the Darlington driver pins, as Ant stated. Your picture shows a connection to a pin usually used as an input, so would not be good as a driver. One pager motor wire should go to one of the Darlington pins towards the opposite corner, any pin 0 to 3. From this picture, they are the ones in tan color, corresponding to the letter F. The other pager motor lead should be connected to either a V1 or V2 pin (with V1 and V2 jumpered) as shown in red and blue further down that page.

Then write your code

high 0

(or whatever pin was used) to make the motor start turning.

By Calculon320 @ Thu, 2008-11-20 17:24

i was confused as well

i was confused as well by the way the darlington works. i thought that if i just plugged my pager motor to an output and a ground, it would work, right? wrong. like my hero robologist explained to me, the gm10s need to be driven by the darlington chip (or some other transistor pair, but save yourself some headaches and just use the chip.

And also, all motors must be driven via the outpins.

The darlington doesn't just boost the outpin's signal, however. It works by taking the V1/V2, running it through the motor, and using the outpin high as ground. (counter-intuitive, i know).

So to hook it up:

1. insert the darlington chip

2. plug one gm10 lead into the V1/v2 (the middle output pin)

3. plug the other gm10 lead into the outpin of your choice (0-3)

4. set the outpin to HIGH

5. do a happy dance.

By Vansu @ Thu, 2008-11-20 18:24

what kind of darlington

what kind of darlington chip? I don't know about this. Is there many type or its just darlington?

By Vansu @ Thu, 2008-11-20 18:29

Oh is it the yellow chip in

Oh is it the yellow chip in the first robot ? so where do I put the darlington chip?

By robologist @ Thu, 2008-11-20 19:06

Not the Yellow chip

But a black chip with the letters "ULN2803" on it, just like shown in the picture. If you already have the yellow chip in the board, then it needs to be removed and the black chip marked ULN2803 should be placed back in, oriented in the manner shown in the picture from the link above.

The yellow chip is a resistor array.

By Calculon320 @ Thu, 2008-11-20 23:15

servos

Also though, be aware that the darlinton ULN2803 cannot power servos. That's what the yellow transistor chip is for. On the default 28x project board, it's either servo OR geared pager.

someone correct me if i'm wrong ...

By Vansu @ Thu, 2008-11-20 19:13

oh I have this, its came

oh I have this, its came with the picaxe kit. Thank you , I think I got it now. I will try this when I am home. BACK TO WORK!

By Vansu @ Fri, 2008-11-21 02:37

I got it working! yeah!

I got it working! yeah! Thanks you guys. now I have to play around with the code.

By robologist @ Fri, 2008-11-21 05:35

Way to go

Glad to hear it, hope you have more fun with it!

By Vansu @ Fri, 2008-11-21 13:24

You bet I did!

I was playing around with the code to get the right beat and I lovin it.

By Ant @ Fri, 2008-11-21 07:42

What did you have to do to

What did you have to do to get it to work?

By Vansu @ Fri, 2008-11-21 13:00

Darlington

I inserted the darlington chip in and I just connect the motor as the picture:

for the code I just wrote low port & high portc& wait..etc

By robologist @ Fri, 2008-11-21 15:24

Not quite there yet.

I'm not sure if there is a reason you keep using the pins near the bottom left of your board, but those have nothing to do with the Darlington driver. The motor may be working now, but the pins you are using connect directly to the PIC microprocessor on your PICAxe board, and you risk burning it out with the motor use. Those port C pins are used as inputs in PICAxe docs, but can be used as outputs as you've found, and have very limited drive. The darlington driver connections are up near the darlington chip, as shown in the picture below. It would be much less risk of your chip if you use one of the connections 0 to 3 designated below for one motor wire, with the other motor wire on the next row.

By Vansu @ Fri, 2008-11-21 18:37

I did tried

For some reason when I connected as you show its not working for me. But I will take your advice and try it again. I don't want to create a fire hehe.

By robologist @ Fri, 2008-11-21 19:42

Programming too

You would have to change the program too. Where you were changing Port C, I believe for the Darlington outputs are all Port B. Programming appears to be high 0 or high 1 or whatever pin you've chosen, from what I've seen of others PICAxe examples. No addressing of the port appears to be needed, if setting the outputs of the darlington driver.