The Inkling pen has a power saving feature, and will stop sending data after about 30 seconds of inactivity. When this happens, you need to briefly lift the pen, and then put it back to the paper to continue sketching. When the pen is in use, the LED on the pen should be lit, and the middle LED on the receiver should react each time the pen touches the paper, to indicate that it is receiving data. If the LED light works, but the pen loses contact with the sensor after working briefly on paper, there may be a defect in the unit, and it will need to be replaced. Please contact Customer Support by clicking Contact Us below.