Voltage Issues

Hello there. I'm a beginner to the arduino and learning about all its functions. I have the duemilanove and was doing an experimental circuit with a serial connection on an analog channel. The program seemed to run fine but the duemilanove seems to be maxing out at 1.07 V. Is there a problem with the MC or is there a way to fix it as I understand that it should operate from a 0-5 V range? Any advice is appreciated.

I advise, then, that you tell us about the circuit connected to the arduino, along with a schematic or photo of the connections.

There may or may not be a problem with the Arduino. There may or may not be a problem with your circuit.

There may or may not be a problem with how or where you are measuring voltage.

If you could provide more details, better answers could be provided.

The program seemed to run fine but the duemilanove seems to be maxing out at 1.07 V.

Have you defined the pin to be an output? Analogue pin 0 is digital pin 14 so a pinMode(14,OUTPUT); is needed to set analogue 0 to be an output.

That's the thing, all of my other runs with previous circuits have been output, but this particular circuit needed the analog pin to be set to input. As for a picture of the circuit, I will need some time to get one up, but all it was was a LM19CIZ-ND temp. sensor connected to the GND and 5V Analog pin with pin 0 set to input. The program itself ran fine, as I tested it, but when I applied an external power source to se what was up, it maxed out at 1.07 V for some reason. Any idea as to what could have caused this?

Analog pin with pin 0 set to input.

You don't have to set anything up as an input analogue 0 will power up as an input.

Have you got a decoupling capacitor across the device like the data sheet says, without it you could get some high frequency oscillations.

When you say maxed out do you mean it will not go higher no matter how much you cool it? What temperature are you cooling it to? What voltage are you expecting? How are you measuring this?

Umm.. it's nothing complicated..just a temp. Sensor...I set it up in the program to be read in serial reader..the range is from 0 to 1023..it should read 1023 at 5V but it reads 1023 at around a little over a volt...any idea what's causing this?

but it reads 1023 at around a little over a volt...any idea what's causing this?

That suggests you are using the 1.1V internal Vref instead of the 5V.

Hmm...alright, how would I be able to change that on the MC?

Hmm...alright, how would I be able to change that on the MC?

analogReference(DEFAULT);

Although it sounds like you have analogReference(INTERNAL); in there, so its just a matter of removing it since it defaults to 5v.