output voltage of arduino

i am powering my arduino with a 9V battery.

i then need to connect a small bluetooth module to the rx, tx, pwr and gnd pins.

the bluetooth module can only take 3volts to 3.3volts though.

is there a way to program into arduino somehow to only output 3volts instead of 5volts?

please let me know.

No, but you can convert the voltage with some simple circuits. This zigbee tutorial has some options: http://mrtof.danslchamp.org/AXIC

OK, don’t pin me down on this one, but if I am not mistaken, all you need is a Voltage divider. (Check the schematics below).
I remember this from high school, which is quite some time ago…

Vout = Vin * R2 / (R1+R2)
In this case Vin = 5V, R1 = 220 ohm and R2 = 330 ohm.

Marcus

You migh wanna check the following thread: http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1147799160

thanks -- your help is much appreciated!!!