Hello folks!
Good morning!
"Houston we've got a problem"
I'm using arduino nano 3.0 with a sensor, paper sensor, when it's not conects to the board, the signal is ok, 0v and 5v, but when the sensor is conected , this value don't go over 1v 
Needing some help haha
Thanks
Yago Aurélio 
are you connecting to a digital or analogue input?
can you post your code?
One wire is in the pin 10, the other to the ground
If the voltage measurement is done without connecting the sensor, the board releases 5v correctly, but if the sensor is connected, it releases almost 1 volt
The code is right
Do you have a link to the sensors datasheet - I do not know paper sensor
It have 3 wires, it's a positive a ground and a signal
A IR emiter, and a IR receiver, like a led and a ldr
I cut the rails to the led, and conected it to the arduino, to only activate the led with the digitalWrite (5v)
EPSON 1390/1400 Paper Detector
I don't have the data sheet
Did you rip that thing out of a printer?
For the LED part: is there any current limiting resistor in place?
Please post complete circuit diagram - with the parts of the sensor in as much detail as possible.