Society of Robots - Robot Forum

Electronics => Electronics => Topic started by: Hawaii00000 on January 16, 2009, 12:43:26 PM

Title: Arduino the power hog!- help with running the Arduino at a lower voltage (3.3v?)
Post by: Hawaii00000 on January 16, 2009, 12:43:26 PM
In a past forum Admin said
Quote
the regulator on the Arduino is garbage. Unsolder it, and put on a 3.3V regulator. Then you can use a 4.8V battery for your Arduino and motors. The only disadvantage is that you need to use a hardware MKII programmer to change the fuse to the 8MHz internal oscillator.
. I'm also thinking about using the lower power version of the ATmega328 instead of the ATmega128 that comes with it. How would I lower the power consumption of the Arduino? If its as easy as changing the regulator why didn't the manufacturer do it?
Title: Re: Arduino the power hog!- help with running the Arduino at a lower voltage (3.3v?)
Post by: Admin on January 16, 2009, 08:26:29 PM
I recommend using the regulator I use on my Axon: L4940V5

It's rated for 1.5A and has reverse polarity protection built in.

As such, you can remove the polarity protection diode. Its the little black two pin chip right above the two cylinder shaped capacitors:
http://arduino.cc/en/uploads/Main/ArduinoDuemilanove.jpg
Just search the part number to verify its a diode on the Arduino. After removal, short the two pins with lots of solder.

Now you can use a 6V battery to power your Arduino.

Now if you wanted to use a 3.3V battery you can use a 3.3V regulator, however most don't have built in reverse polarity protection so you'd still need the diode. Also, you'd have to replace the crystal with one for ~11MHz.

Quote
If its as easy as changing the regulator why didn't the manufacturer do it?
The Arduino is designed to be ultra cheap by sacrificing quality and features.

My Axon is the opposite, I packed it with quality and features, at the cost of a higher price.
Title: Re: Arduino the power hog!- help with running the Arduino at a lower voltage (3.
Post by: Hawaii00000 on January 16, 2009, 08:40:45 PM
What would be the consequence of changing the crystal. Would it mess up the all the serial connections.
Title: Re: Arduino the power hog!- help with running the Arduino at a lower voltage (3.3v?)
Post by: Admin on January 16, 2009, 09:04:55 PM
The only consequence is that your processor is now slower. Everything will still work.

You will notice that any delay based code (that uses cycles and not interrupts), will take longer. I'm not sure if the Arduino IDE cares about processor speed - depends on how they programmed it.
Title: Re: Arduino the power hog!- help with running the Arduino at a lower voltage (3.3v?)
Post by: Kirk on January 16, 2009, 10:07:32 PM
The Arduino IDE has a file called board.txt (If I remember correctly)  It is the way that the menu that allows you to select the NG. Vs. Lillipad vs. newer board etc.  You can make a new board entry and set the processor speed and chip type.
Kirk