That's very strange. I have no clue how you are getting such high voltage from the 3.3v pin.
If you are using analog sensors you can set
in your setup, and then connect your sensor's power pin to the "AREF" pin to make sure the reference is always the power. So if it fluctuates, it will compensate.
You can read more here: http://arduino.cc/en/Reference/AnalogRe ... rence.AREF
Nasicornis wrote:Very good article about sht15! I have some sensors like this and I try to take the most accurate measurements I can. What I've noticed is that when I connect a sensor to arduino in 3.3 volt output, before the connection the voltage is 3.26 and after the connection is 3.94v. This is one strange problem. A second one is that sometimes the voltage goes to 4.86v. I disconnect the power and ground and leave the SCK and DATA connections of sensor connected to arduino. I measure the voltage again in vcc and ground of the sensor and I get again 4.86v.
Can someone give to me a reasonable explanation for these facts? I want to calibrate the sensors I have and I want to be as precise I can be by supplying 3.3v in the input but these two problems mess things up!
Thank you in advance!