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Topic: ardweeney power ? mystery overload (Read 657 times) previous topic - next topic

May 26, 2011, 05:15 pm Last Edit: May 27, 2011, 07:26 pm by tomswell Reason: 1
with FTDI breakout board attached my ardweeney powers up , loads and runs sketch that drives a MAX7219 & 2- seven segment digits .
but I can't run it on batteries or regulated supply to pins;
most examples imply all GND connections are common and that some larger loads such as an RC Servo are best not sourced thru regulated supply going to ATMega
what pins to what ?
#7 +5V
#20 +5V
#22 GND
#8 GND
when these connections are made having removed FTDI board sketch runs briefly and then overloads

johnwasser

The 'ardweeney' doesn't have a voltage regulator so you need to provide a voltage within the operating limits of the ATmega chip.  The Absolute Maximum operating voltage is 6.0V.  The recommended range is 1.8V to 5.5V.  A 9v battery should NOT be used without a regulator.  You can use 3 AA batteries (4.5V) without a regulator.

Pins 7 (VCC) and 20 (AVCC) should be connected together on the board so it doesn't matter which you use.  Same for 8 and 22 (GND).
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floresta

#2
May 26, 2011, 05:37 pm Last Edit: May 26, 2011, 05:39 pm by floresta Reason: 1
Quote
I've read conflicting words about using 9V battery un-regulated ?

I can't understand why there should be any conflicting information.  The Ardweeny board does not have any sort of power supply.  The ATmega328 has an absolute maximum operating voltage of 6.0V with the added stipulation that "Exposure to absolute maximum rating conditions for extended periods may affect device reliability."  This means that you should run your Ardweeny from a regulated +5 volt source.  An unregulated 9V battery is out of the question unless you have a large supply of Ardweenies.

If you want to use a regulated supply then you must first disconnect the FTDI breakout board.  You can feed the regulated voltage to the FTDI header (+5V on pin 3 and GND on pin 1) or to the breadboard pins.  Connect +5V to #20 and/or #7 and connect GND to #22 and/or #8.  


Don

Damn -  John beat me to it again.  I had better take typing lessons.  At least we agree so we haven't added to the 'conflicting words'.

AndyCC

#3
May 26, 2011, 09:47 pm Last Edit: May 26, 2011, 10:17 pm by AndyCC Reason: 1
Ardweeny has a "backpack" to power off 9v:

http://www.solarbotics.com/products/kardwbp/

but if that's all you want to do, a 7805 and a couple of capacitors are all you need:

http://itp.nyu.edu/physcomp/Tutorials/ArduinoBreadboard

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