servo robot please help

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I am a beginner and this is my first robot. I was thinking of building it with an Arduino Leonardo, Adafruit Motor Shield, ultrasonic sensor and three 9g servos. I decided to use servos since motors are heavier, costs more and are hard to mount. I wanted to keep the robot small, compact and lightweight. I am planning to put the third servo on the header pins. So here r my questions:

  1. What type of battery should i use (voltage and amps)?
  2. Should i power it up thru the terminal block or the barrel jack?
  3. Are heat sinks necessary?
  4. Whats the function of the vin jumper?
  5. Will these servos heat up?
  6. Will my servos be damaged if i modify them?

please help
thank u

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  1. What type of battery should i use (voltage and amps)?

Round ones, of sufficient voltage and current to power your servos.

  1. Should i power it up thru the terminal block or the barrel jack?

Yes, indeed.

  1. Are heat sinks necessary?

If you need to wash the heat, yes.

Heat sinks for what?

  1. Whats the function of the vin jumper?

No idea what you are talking about.

  1. Will these servos heat up?

All electric motors generate heat. How much depends on the load placed on them.

  1. Will my servos be damaged if i modify them?

If you modify them with a sledge hammer, most likely they will be damaged.

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For your first robot, you might consider a kit with all the parts sorted out, or a simple bot like below.

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Servo drive robots are very easy to control, and there is at least one place I know that sells them - fairly cheap.
http://www.budgetrobotics.com/category/Robot-Chassis-Kits-161

9g servos are probably a little underpowered for driving a non-tiny bot, but several places sell "standard" servos [~44 oz-in] already modified for continuous rotation, although it's not too hard to do yourself.

https://www.google.com/search?q=rc%20servo%20continuous%20rotation

There are also a lot of inexpensive motorized bases around that use the little yellow motors. They can be controlled with a small h-bridge board, L298 or L9110S.
https://images.search.yahoo.com/search/images?&p=ebay+smart+car+robot
https://images.search.yahoo.com/search/images?&p=ebay+h-bridge

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so ur saying that i shud use the standard servo?
one more thing, shud i power it up thru terminal block or the barrel jack?
and lastly, what battery shud i use(volts and amps)?

p.s. can i add a third servo to the robot?

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For a first robot, it's easiest to start with servo drive, and use the 44 oz-in servos. You can always go to motor-drive and h-bridges for your 2nd robot.

The 44 oz-in servos will provide more torque than the 9g servos, so you can build a larger bot that can mount a regular UNO board and a range of sensors, like sonars, Sharp IR rangers, etc. Once you start adding things, the weight starts to build up, and you can overload the smaller servos.

The best sensor system is to use a panning servo with sonars and/or Sharp ranger on top. The 9g servo should work fine for this.

Also, for a reasonable price, you can buy a complete kit that includes all of these elements. This uses motor-drive, but includes the h-bridge. This is what I would do myself. Similar available from many other places.

This includes the battery holder, plus you'll notice the controller board has 3-pin headers mounted on it, so it's easy to plug in servos and sensors. You see a lot of people interfacing Rduino boards the following way, but this is a really crappy way to do things.

1064×803 129 KB

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Ok, but im not really interested in big robots. I want my robot to be no bigger than twice the size of the board. I am using thin wood as the base. This is the shield i am using , Adafruit Motor/Stepper/Servo Shield for Arduino v2 Kit [v2.3] : ID 1438 : $19.95 : Adafruit Industries, Unique & fun DIY electronics and kits. The overall weight shud be close to 500 g.
So can two 9g servos handle it, or shud i go with standard servos instead?
i think standard servos are a little too big. Anything from micro to sub micro would be nice

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I am using three servos (each 4.8v), sonar( 5v) arduino board and an adafruit motor shield (1.2v) -www.adafruit.com/products/1438. Shud i use lipo or li ion? And what voltage shud it provide? The battery shud be lightweight. I was planning to use cell phone batteries (soldered together). 9v seems to be low.
PLEASE HELP!!!!!!!!!!!!!!!!!!!!!!!!

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See this discussion about batteries.

http://forum.arduino.cc/index.php?topic=323706.0

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BTW i decided to use a 7.4v battery.
Thanks for helping me with dat!

i still have a couple of questions

  1. How much load can 9g continuos rotation servos pull. Can two of these servos pull at least 500g?
  2. Should i use servos with more torque?
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Some things you're just gonna have to find out for yourself.

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  1. How much load can 9g continuos rotation servos pull.

Powered by what voltage? At what current level? With what sort of mechanism? With what dimensions? How fast?

Can two of these servos pull at least 500g?

Certainly. If the voltage and current are adequate. If the appropriate mechanism is used. If you can wait long enough.

  1. Should i use servos with more torque?

Absolutely. I suggest a couple of car starter motors.

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  1. How much load can 9g continuos rotation servos pull. Can two of these servos pull at least 500g?

I'm not sure I've seen a 9g continuous rotation servo. 9g servos are quite small and the cheap ones easily strip their gears.

  1. Should i use servos with more torque?

Probably. You have been a link to a simple servo based bot. You probably need to build/copy that bot as you don't seem to currently have the capability to design/build one on your own.

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well it seems i had made up my mind. im gonna use 2 TowerPro MG92R servos and a 9g servo for panning.
7.4v 1500 mAh battery. I think the micro metal type servos provide more torque than nylon gear.
Anyway.... thanks guys!

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