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Topic: Using 3 servos with power supplying (Read 1 time) previous topic - next topic

slmsmsk

Hi everybody,
I am new in arduino. I want to control 3 servo with arduino mega 2560, but the power is not enough for 3 servos. I have 2 battery(9v).
How can I

  • use its with arduino?

  • do pin connection for battery?

  • increase the output of arduino?


zoomkat

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slmsmsk


A way to power the servos.



Thank you.
I know it, I want to learn "how is 9v battery pin connection to arduino?"

TomGeorge

Hi, what sort of 9V battery?
If its one of those "transistor" batteries with the stud clips on top the you use in a smoke detector forget about it, they will never provide the power and longevity that you require.
Servo's can consume over 500mA each, so you will need a supply for the servos and a supply for the arduino.
Or a main supply of say 12vdc and regulate to 5V or 7V  for the arduino, and a separate 6Vdc supply for the servos.

Tom.... :)
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gelfling6

Tom, a project I'm still hammering the kinks out of (mostly software), uses a 12V gel cell as the main supply, but I have it fed to a LM7809 regulator, the output of the 7809 is split between the coaxial plug for the arduino (Roughly 1.5-Amp 9V), and to a separate LM7805 5V regulator to power the motors, servo, PING range finder, 3 IR line followers, and a series-1 XBEE with the Adafruit adaptor board. (which you normally connect the FTDI USB to Serial cable.) (the 7805 also maxing at 1.5-Amp.)  Both regulators are common-grounded, and mounted to a 2" square X 3/16" finned heatsink I scavenge from an old ATX supply. This way, the sensors, all motors, and the radio are powered off a separate 5V supply. Only lines from them are their signals going to the Arduino's I/O pins.

Otherwise, if you try to draw more than 750mA from the +5V power pin on the Arduino, the on-board regulator will overload, and shut-down. (because you're drawing more amperage than it can provide, and the weak voltage that does remain is too weak for the ATMEGA chip to use.)    I just got 50X of both regulators from a China supplier off eBay for about $20 (USD). (replacing the regulators I've scavenged from old gadgets, and broken the pins on from over-use.) 

I had thought it wouldn't cause a problem, but NEVER back-feed an external +5V to the +5V pin of the Arduino. On some models it could fry the switching circuit that shuts-off the USB +5V supply, when using the external Coaxial plug (7-9V dropped to +5V by the on-board regulator.)  I think on the MEGAxxxx boards it really does fry the USB-Serial chip.

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