Knob controls on stoves have now become a thing of the past. First seen on flameless ceran stoves, Reed Sensors are used to control the various power settings for each burner. The Reed Sensor eliminates the need for knobs, electronic gadgetry and hall effect sensors; the latter two of which require added power and additional circuitry. In addition, this particular Reed Sensor design allows for child proofing, in that burners will not be indiscriminately turned on.
Here is how it works: On the surface of the oven and near one of the ceran elements, a sliding device with an integrated magnet is installed. Reed Switches are mounted just below the surface. As the sliding device (magnet) is moved, it will trigger the various Reed Switches, which in turn will activate different power settings.
When the stove is not in use, the sliding magnet may simply be removed and stored in a safe place. Thereby, if and when children are playing in the area, they will not inadvertently be able to turn on power to any of the stove elements.
Full application write-up: Efficient Ceran Stove Burner Control Sensor