Mega ADK power lack

Using Arduino Motors, Mechanics, Power and CNC
1

Hello guys,
I'm trying to realize the mover-bot project found here and all works fine (communication between client, server, and arduino board) until I connected the motors, there's unsufficient power to let them work so the behavior that occurs, is the phone disconnecting from the adk and reconnecting and so on.. The explanation of this phenomenon, is that the connected phone (Galaxy SIII) to the Mega Adk, is charging from the power provided by the arduino via the usb host (Arduino powered by the usb, and 9v battery) so it can't find enough energy to power and drive the motors. (with leds instead of motors all works fine)

Can somebody help with this ?

Thanks

2

Can somebody help with this ?

You should NOT even consider having the Arduino power the motors. Use a separate power supply for the motors.

3

PaulS:
You should NOT even consider having the Arduino power the motors. Use a separate power supply for the motors.

Of course, I'm using this motor driver powered by a separeted 9V battery,

but one question, if the board is connected to pc USB is there a chance that it bypassed the external power ?

4

powered by a separeted 9V battery

One of those useless rectangular ones? Get a REAL battery.

5

PaulS:
One of those useless rectangular ones?

:smiley: haha but it works like a charm even with steppers

PaulS:
Get a REAL battery.

Any suggestions please ?

6

haha but it works like a charm even with steppers

I am not convinced.

Any suggestions please ?

If the battery you have works like a charm, why are you complaining about lack of power?

7

Hi,
Can you please post a copy of your circuit, in CAD or a picture of a hand drawn circuit in jpg, png?

Can you please post a picture of your project please in jpg, png?

Thanks Tom..... :slight_smile:

8

Does the motor driver have a VIN connect jumper or trace? If so, remove the jumper or cut the trace. Also, you could add caps across the power terminals(make sure you connect them the right way-they could explode :o)

9

TomGeorge:
Hi,
Can you please post a copy of your circuit, in CAD or a picture of a hand drawn circuit in jpg, png?

Can you please post a picture of your project please in jpg, png?

Thanks Tom..... :slight_smile:

Hi Tom, this is a quick and dirty schematic of the circuit (attached)

Yesterday I've tested the circuit with external ac adaptor 8v 1.8A and the motor worked for a second and after that I got the same behavior of disconnecting accessory mode, may be when it reached a peak of current consumption.. I'm sorry, maybe I've used wrong technical terms, i'm newbie to all of this.

Thanks for the help

circuit.jpg
circuit.jpg1280×720 122 KB

10

Isaac96:
Does the motor driver have a VIN connect jumper or trace? If so, remove the jumper or cut the trace. Also, you could add caps across the power terminals(make sure you connect them the right way-they could explode :o)

Will try with the caps this afternoon :wink:

thanks

11

Hi,
How are you powering the servo, again not off the arduino we hope?

Tom.... :slight_smile:

12

TomGeorge:
Hi,
How are you powering the servo, again not off the arduino we hope?

Tom.... :slight_smile:

yes, it's off the arduino, is it wrong to do that ?

13

Your motor driver board seems to have a voltage regulator. Does it output anything on the VCC pin?

14

Hi,
Using the mega as the power supply for the servo, will mean that you are possibly overloading the mega's regulator.

Servos should always be given their own power supply to ensure the controller has a constant 5V.

The servo can draw up to 1A, if it is even a small one, on load peaks.
This will cause the mega supply to drop.
The drop will usually cause the mega to RESET.

Tom... :slight_smile:

15

Isaac96:
Your motor driver board seems to have a voltage regulator. Does it output anything on the VCC pin?

To be verified this night (y)

16

TomGeorge:
Hi,
Using the mega as the power supply for the servo, will mean that you are possibly overloading the mega's regulator.

Servos should always be given their own power supply to ensure the controller has a constant 5V.

The servo can draw up to 1A, if it is even a small one, on load peaks.
This will cause the mega supply to drop.
The drop will usually cause the mega to RESET.

Tom... :slight_smile:

Logic explanation, I will give a try this night, and keep you updated...

thanks :wink:

17

Hi guys,
I'm sorry for this late, finally I got things working as desired, the trick was as you said powering the servo externally with a common ground with the arduino board

Thanks for your help.