External power supply not working?

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hi,

  i'm using arduino uno motor driver shield. when arduino connected pc via usb cable fine: motor turns wheels. when connect 9v battery, nothing happens, except status led blinks few times.

i've seen in troubleshooting section:

quote
why doesn't sketch start when i'm powering board external power supply? (arduino diecimila or earlier)
because rx pin unconnected, bootloader on board may seeing garbage data coming in, meaning never times out , starts sketch. try tying rx pin ground 10k resistor (or connecting rx directly tx pin).


but didn't me @ all.


please help!!

small 9 volt batteries have little current capacity power motors/servos , other components have higher current requirements, need external dc power source has higher current capacity.

lefty


Arduino Forum > Using Arduino > Installation & Troubleshooting > External power supply not working?


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