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Author Topic: Building a Robot for the First time  (Read 1562 times)

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Offline hoohoohamaTopic starter

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Building a Robot for the First time
« on: March 15, 2011, 07:47:11 PM »
I am only ten years old. I am trying to build a robot, but my battery is too heavy and my motors are too weak. I am using a R/C sabertooth and I need 6 volts at least to run it. I have tried AA, lithium, and Ni Cad, but each has it's own problem. I am low on money and I need something around thirty bucks. The price can go higher a bit like ten bucks, but the battery needs to be much less than a pound so the robot can move.

Offline rbtying

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Re: Building a Robot for the First time
« Reply #1 on: March 15, 2011, 07:56:15 PM »
You probably want a 2-cell lithium-polymer battery pack.  It is the lightest solution - RC battery packs are generally good.

Example: http://www.batteryspace.com/customizedli-ion14500battery74v750mah555whwithpcbcustomconnector.aspx

It is, however, somewhat dangerous to use Lithium-Polymer chemistries without proper precautions and chargers - be well aware of the risks.

If weight is less of an issue, six NiMH cells in series would provide 7.2v and have little risk of explosion.  You can provide this by simply using a 6-AA battery holder. 

Offline joe61

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Re: Building a Robot for the First time
« Reply #2 on: March 15, 2011, 08:08:11 PM »
If weight is less of an issue, six NiMH cells in series would provide 7.2v and have little risk of explosion.  You can provide this by simply using a 6-AA battery holder. 


Another alternative is a 5-AA holder from Solarbotics: http://www.solarbotics.com/products/bholdaa-5cell-p/

It would save the weight of a battery and still give 6V.

Joe

Offline rbtying

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Re: Building a Robot for the First time
« Reply #3 on: March 15, 2011, 11:34:53 PM »
His Sabertooth apparently cuts out at 6v - OP would get longer runtimes at that cutoff if the nominal voltage was higher.  But a 5-AA pack would work too, yes.

Offline hoohoohamaTopic starter

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Re: Building a Robot for the First time
« Reply #4 on: March 18, 2011, 02:31:30 PM »
 :)thanks, but I had already tried AA. I used four of them, and it was too heavy. Are there any alternative choices?

Offline newInRobotics

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Re: Building a Robot for the First time
« Reply #5 on: March 19, 2011, 03:13:23 PM »
I used four of them, and it was too heavy.
What is overall weight of Your robot? What sort of robot is it? How many motors does it use? Are they geared motors or not?

It is really hard to believe that even small dc motor would not be able to carry 4 AAs  ???
"Computer games don't affect kids; I mean if Pac-Man affected us as kids, we'd all be running around in darkened rooms, munching magic pills and listening to repetitive electronic music." - Kristian W

Offline Soeren

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Re: Building a Robot for the First time
« Reply #6 on: March 19, 2011, 07:43:28 PM »
Hi,

:)thanks, but I had already tried AA. I used four of them, and it was too heavy. Are there any alternative choices?
Yes... Gear down the motors to get the required torque - if you just expect it to drive the 'bot directly (eg. with a wheel directly on the motors output axle, you'll not get it to move.

And to get faster and more precise answers, post a complete description of the problem, the solutions you tried and the involved components etc. in your first post.
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 hoohoohamaTopic starter

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Re: Building a Robot for the First time
« Reply #7 on: March 21, 2011, 03:10:59 PM »
I am not really very good at robotics, and also there are no robotics groups except a Lego one. I am not very good with structure also, and I only have cardboard to work with. I need a geared motor with lots of torque, and not alot of speed is needed for this. My robot is pretty light, and I know that it is much less then a pound. I have not really made any measurements.

Offline Conscripted

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Re: Building a Robot for the First time
« Reply #8 on: March 23, 2011, 07:11:37 AM »
I'm glad that you are starting to learn about robotics at such a young age. Please don't get discouraged. It can take a lot of time a practice to learn all this stuff. What type of robot are you building? Where did you get your motors? There are many of us here to help you but we need to know what you are trying to do and what pieces you are using to do it.

Let us know so we can help.

Conscripted

Offline hoohoohamaTopic starter

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Re: Building a Robot for the First time
« Reply #9 on: March 25, 2011, 02:36:28 PM »
I mostly get my stuff from www.robotcombat.com . I am trying to build an r/c robot. I already have a good transmiter and receiver and I have already connected it correct. I made a test run before, and the motors worked but they were sometimes going out of control. As for what pieces I am using, I am using cardboard as my chassis, and I am planing to build a makeshift caster in the back of my robot. Also, I don't have much money left to build it.P.S. I am going make two wheels out of cardboard, and I hope that I can directly attach it to a motor.

 


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