Society of Robots - Robot Forum

Electronics => Electronics => Topic started by: backman on February 22, 2011, 10:06:56 AM

Title: 50$ robot only one servo is working
Post by: backman on February 22, 2011, 10:06:56 AM

Hi,
I have a little problem with my 50$ robot. I do everything what is in HOW TO and when i power it up only one servo is acctually responding on changes of light. Another one is still going in one direction. It's not fault of the servo because when I give there another one it's doing the same. Any ideas where the problem can be?
Sorry for my bad english.

Title: Re: 50$ robot only one servo is working
Post by: waltr on February 22, 2011, 10:15:30 AM

Re-check the output of the LDR sensors with a voltmeter.

Also, go through the forum threads (search '$50 robot') and read what other people have had problems with and the solutions.

Title: Re: 50$ robot only one servo is working
Post by: arrrrgon on February 22, 2011, 10:29:17 AM

Make sure your grounds are connected properly.  This caused me problems.

Title: Re: 50$ robot only one servo is working
Post by: hoosier122 on February 23, 2011, 10:48:38 PM

Switch the servos. That will tell you if it's a problem with the servo or circuit feeding the problem servo. My guess is it's a problem with one of the light sensors.

Title: Re: 50$ robot only one servo is working
Post by: backman on February 24, 2011, 05:37:43 AM

Yes is it problem with one of the light sensors. When I checked the output one of them has 1.9V the second one has 0.4V. When I tried other light conditions the second one changed just a little bit to 0.5V. Where can problem be? I tried switched resistors and didn't help.

Title: Re: 50$ robot only one servo is working
Post by: backman on February 24, 2011, 07:15:42 AM

It was microcontroller problem. Thanks

Title: Re: 50$ robot only one servo is working
Post by: dmclifton on February 24, 2011, 09:07:06 AM

Would you be willing to clarify? 'microcontroller problem'? Just curious.

Title: Re: 50$ robot only one servo is working
Post by: backman on February 24, 2011, 09:52:18 AM

When I changed atmega8 for another one. Then it worked. Probably one of the pins was wrong.

Title: Re: 50$ robot only one servo is working
Post by: hoosier122 on February 24, 2011, 10:48:45 AM

Was it bent and not making contact?

I'm surprised it worked at all if there was a problem with the micro-controller....glad you got it figured out.

Title: Re: 50$ robot only one servo is working
Post by: backman on February 24, 2011, 02:04:08 PM

No it wasn't at all. I tried every contact with multimeter if there is contact and everything was OK. I am suprised too. But it is working and that's important

Title: Re: 50$ robot only one servo is working
Post by: backman on February 26, 2011, 05:22:21 AM

The problem is not solved. When I tried it today it just didn't work properly. When I give light to one photoresistor just one servo reacted. But I noticed when I unplug the good one servo the bad one is working well. When I plug it back again it doesn't work.

EDIT: I changed the LED because the old one was burned out. When I give there another one I found out there is some problem with power because the LED just blink and then nothing. I tried multiple power sources but still it is doing the same.