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Author Topic: $50 robot no power?  (Read 16291 times)

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Offline Webbot

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Re: $50 robot no power?
« Reply #30 on: June 03, 2009, 10:05:44 AM »
When you say 'one direction' then do you mean you want the robot to go forwards, say? You may find that both motors are turning clockwise but because they are mounted on opposite sides of the chassis then the robot is just spinning. So you need to make one go clockwise and the other anticlockwise in order to go in a straight line.
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Offline dfoley23Topic starter

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Re: $50 robot no power?
« Reply #31 on: June 03, 2009, 10:23:28 AM »
yes i do mean forward can this only be done by flipping it becasue the way i designed my robot i cant really adjust the servos posistion how about programming it with different values like negative values? and how do i know which wheel is servo_left in the code is PD0 servo left thankyou
« Last Edit: June 03, 2009, 10:36:51 AM by dfoley23 »
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Offline Webbot

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Re: $50 robot no power?
« Reply #32 on: June 03, 2009, 11:00:30 AM »
Make servo_left go forwards and servo_right go backwards - the robot should travel either forwards or backwards.
Swap the code ie make servo_left go backwards and servo_right go forwards - the robot should now travel in the opposite direction.
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Offline dfoley23Topic starter

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Re: $50 robot no power?
« Reply #33 on: June 03, 2009, 06:13:51 PM »
I dont think the photocells are responding to light, I got it to go straight what would i do to check the voltages of the cells and see if they are still good
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Offline Webbot

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Re: $50 robot no power?
« Reply #34 on: June 03, 2009, 06:27:58 PM »
Got a volt meter (DMM)?
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Offline dfoley23Topic starter

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Re: $50 robot no power?
« Reply #35 on: June 09, 2009, 03:42:05 PM »
heres a video it mostly spins to the left unless a shine a flashlight on the right.
[youtube]http://www.youtube.com/watch?v=rDpqNRssOPc[/youtube]
and i programmed my LED to come on with LED_on(); but it didnt work i was just trying this to see
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Offline SmAsH

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Re: $50 robot no power?
« Reply #36 on: June 09, 2009, 03:47:45 PM »
have you tested it out with no photocells plugged in?
also, have you tried adjusting the values in the source code?
i would say adjusting some values for the thresholds may change something...
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Offline dfoley23Topic starter

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Re: $50 robot no power?
« Reply #37 on: June 09, 2009, 04:05:15 PM »
i just tested it with no photocells and it drove straight, thats good. so its probbly either the photocells or the programming right. at leat its narrow, i have tried lowering the threshold value to 5 and 3 no luck i also tried some others but i think the write failed trying now to 12.
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Offline SmAsH

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Re: $50 robot no power?
« Reply #38 on: June 09, 2009, 04:06:59 PM »
i think one of your photocells is busted mate  :-\
try rigging up another one and then try again.
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Offline Webbot

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Re: $50 robot no power?
« Reply #39 on: June 09, 2009, 05:27:16 PM »
If you know suspect the photocells then try swapping the cells  over ie left<=>right. If the robot movement moves with the cells then the problem is with one of the cells.
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Offline dfoley23Topic starter

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Re: $50 robot no power?
« Reply #40 on: June 09, 2009, 07:31:01 PM »
ok check this video out.[youtube]http://www.youtube.com/watch?v=PGqqN3pM-nM&feature=channel_page[/youtube] i dont know what makes it go straight in this room but it seems to make desicions to follow the light but then goes right under the table. instead of having issues with turning right it just doesnt see the dark could it be the sensors or the microcontroller are to slow. sometimes if i hold my hand over the left sensor it will just continue going left until after a little while then it goes straight. I am going to buy new photocells and make two new ones to test as soon as i can. if i dont get it to work ill just move onto the Ir sensor upgrade that seems more practical anyway. btw can i use a sonar sensor instead thats what they have at radio shack.
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Offline Webbot

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Re: $50 robot no power?
« Reply #41 on: June 09, 2009, 08:33:24 PM »
It seems to react to the torch on the left sensor but not on right sensor.
Do you have a voltmeter?
If not then it could be worth using the following hardware setup:
one sensor => one ADC input => read value (as decimal) =>use rprintf to print value to UART
If you dont hava a TTL serial to R232 card yet and/or breadboard then I suggest you buy one (or make using MAX232) its a great debug tool as you can then output to Hyperterminal/RealTerm on your PC.
Then you can use your PC to act as a multi-meter.

If all fails then my advice is dont get for Sharp IR detector They are too precise. You need something with a wider detector beam - ie sonar mounted on a servo so it can scan. Check my vid http://www.societyofrobots.com/member_tutorials/node/280 Although written in C++ its also very simple in C.
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Offline dfoley23Topic starter

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Re: $50 robot no power?
« Reply #42 on: June 17, 2009, 07:55:22 PM »
for the IR sensor upgrade in the tutorial, will this servo be ok instead of another Hitec 311

edit:nevermind im buying a Hitec i have to order some mounts anyway my wheels are crooked and my servo didnt come with any vertical mounts so im also buying some of those
« Last Edit: June 17, 2009, 08:23:41 PM by dfoley23 »
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Offline SmAsH

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Re: $50 robot no power?
« Reply #43 on: June 18, 2009, 06:16:34 AM »
ps: most servos don't make much difference...
they are usually interchangeable with each other.
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