Power Requirement

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In the File attached to this post I have indicated the External power supply which I need to use for this Uniboard v1.1 which has an atmega chip aboard.I need to drive motors of rating 12V so how much is the power requirement for the external power supply to the uniboard for the purpose to be ahieved?
Besides the fact I have no clue how to connect DC batteries/cells to this external power supply plug when I dont have access to the USB connection in a mobile bot.
Someone please help me out :cry:

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Quote:
I need to drive motors of rating 12V so how much is the power requirement
POWER is a factor of voltage times current and you are telling us half of the story. So it's like asking "How long is a piece of string"? :?

John Samperi

Ampertronics Pty. Ltd.

www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly

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Sincerely, my apologies for the same but the motor I bought is a Side Shaft Gear motor which only has a 12V volt,60 rpm rating mentioned as its rating specifications. :(

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But that means NOTHING power wise. Do you have a part number? A datasheet?

John Samperi

Ampertronics Pty. Ltd.

www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly

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There's absolutely nothing.I even searched on the net http://www.nskelectronics.in/mot...
It shows the same side shaft gear motor with the specifications I mentioned above.
Even if there isn't any bar on the current limiting aspect and assuming I need to plug in a 9V voltage supply to be driving the motors as I found out from some sources across the net,how do I achieve the connection in a mobile bot from a battery/cell into the DC adapter power plug which has been encircled in the image above.

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Looking over the schematics for the board, I see it has an on board voltage regulator. When powered from the USB port, the port provides the power for the CPU, but not for the motors.
Power from the DC power connector is used to for the motors, and also regulated down to provide +5v for the rest of the circuitry.
The motor driver is an L293D. This typically drops a couple of volts and provides the rest to the motors. With a 12v motor, you'd probably want to provide 14v to 15v to the DC power connector in order to get the full 12v on the motor. If that's too hard to find, most motors will run quite happily with somewhat less voltage, so a 12v power supply would do fine. Just don't expect to get full power from the motors with a reduced power supply voltage.
The L293D can provide a maximum of 600mA to each motor before you risk burning it out. Your motors must use less current than this or else you'll have to find some other way of driving them. You can test this by putting a current meter in series with your motor and measuring how much current they draw when under load
Your DC power supply will need to be able to supply all the current used by the motors, plus the amount of current required by the CPU itself. It won't hurt to use a power supply with a bit more current capability than the minimum required. Unless there's something really power hungry there that I've missed, a power supply capable of supplying 12v@1.5A should be more than enough to handle anything you are likely to connect to that board.

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You need to ask the supplier as no one would have any idea. You see the motor above the sideshaft type has

Quote:
•No-load current = 60 mA(Max), Load current = 300 mA(Max)
you MUST find from the manufacturer that information. If it has a part numer you may be able to google for a datasheet.

John Samperi

Ampertronics Pty. Ltd.

www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly

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@ Chris-Mouse thanks a ton but the question that still stands and to which I have no idea about is "how do I achieve the connection in a mobile bot from a battery/cell into the DC adapter power plug which has been encircled in the image above"
i.e. how do i connect a battery to that power plug.No idea since this is my first project on embedded applications.

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Quote:
how do i connect a battery to that power plug
You PLUG IT IN. :) Can you solder? Get a suitable battery holder and a bit of wire and a suitable DC connector and put it all together.

John Samperi

Ampertronics Pty. Ltd.

www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly

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Thank you so much Chris-Mouse and John :)

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How about running the motor from a 12 Volt power supply & measuring the current with an ammeter. The more mechanical load you put on the motor, the more current it will draw. be careful of stalling the motor as the current goes sky high & will burn tracks on boards & wiring (fusing is a good idea).
If you have a multimeter, don't forget to re-configure the multimeter for measuring current, put it the highest range first, & then CONNECT IT IN SERIES WITH THE LOAD.
(You cannot measure the current across things in the same way that you can't measure volts through things.)

Charles Darwin, Lord Kelvin & Murphy are always lurking about!
Lee -.-
Riddle me this...How did the serpent move around before the fall?

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Ball park 1-2 amps stall current half amp running....