I finished the electronics to drive the ‘waterfall’ for the Nachtmusic performance. The electronics switching the water pump can be adjusted to switch off the waterpump when the noise near the waterfall (people talking, music) is too loud.

The electronics consists of the following parts:
1. An opamp switched as a peak detector (measuring the amplitude of the incoming audio).
2. A comparator. Comparing the amplitude with a variable (potentiometer) dc-threshold.
3. Schmitt trigger, to avoid the relay switching on/off constantly.
4. A circuit with two transistors creating an adjustable time delay for switching on and switching off the relay.
5. The relay itself.
6. The +12V power supply with a 7812.


2015-04-03 20:40:20
Comments List
I like your invention. As I understand your hardware can manage only one power consumers. I was searching here http://hardware.nl/weidmuller of an upgraded version of the switch but I couldn\'\'t find something. Or maybe I\'m wrong and there are no any switches to manage more then one power consumer?