Same experience.
Here I talk about the version two of the whisperer.
Hope this could help other users:

By now the instructions that comes with the app says to rapidly press six times the power on button. But doing so doesn’t reset the sensor.
The relatively rapid pression should wait for the light that has to turn on before pressing again the button and turn the sensor off for three times. (Six pressions)

Only on the seventh pression the sensor turns on in programming mode: white blinking light.