The emWave Ear Sensor is quite sensitive and can respond to ambient light.
When the ear sensor is not connected to you, the sensor pads can play off of each other and keep going for a short time. Make sure that you stop the session, if you remove the ear sensor.
If you have an emWave2 handheld unit, you can try this demonstration.
Please note: This demonstration will not work on Inner Balance.
Plug in the ear sensor (don't put it on) and start the emWave unit.
Pinch open and closed the ear sensor, real slow to simulate a heartbeat using the ambient light in the room.
You'll see the small, blue light in the lower left corner of the emWave begin to flash.
This is indicating that the sensor has acquired a pulse and that the senso is working correctly.
It's merely a demonstration of the sensitivity of the ear sensor and in no way indicates a defect or malfunction of the emWave unit or ear sensor.
Please be assured that when it is on your ear lobe, it is only registering you.