Art Project "Electronic Prayer Detector" A bit of fun...

[johnnyatom]

I need some advice for a simple electric circuit for a little art sculpture "thing" I want to built. It's supposed to be a machine that "detects" prayers as they pass by on their way up to heaven.
It will incorporate an old 0-10 volt D.C. voltmeter which will flicker (as it detects passing prayers), and a simple shop bell, that I want to "ding" every now and again as a prayer is registered. There is an antenna that is connected to the voltmeter made out of brass bits.
I need to know how to make the voltmeter flicker, and also how to make the bell randomly ding. For the bell I was thinking of using a model railway solenoid, or some kind of doorbell thing.
As you can probably tell I know next to nothing about electronics!
I'll post a drawing presently to show you what it will look like.
This is my first post by the way, so Hello!
All the best,
Johnny.

 

[klystron]

Use a white noise generator as a source. See **broken link removed**
Amplify the white noise signal to the range of your voltmeter.
Use a comparator set at 5 V . The output of the comparator is used to switch a transistor with a solenoid collector load ; that's the bell

 

[luben111]

the best choise is to use some ready controller (PLC) where you can program everything you want. OMRON offers such PLC controllers on quite reasonable price - OMRON INDUSTRIAL AUTOMATION|CPM1A-10CDR-A|PLC, 10 I/O, AC, RELAY OUTPUT | Farnell . I'm sure you can get even cheaper PLC. The beauty of such solution is that it's universal, you get it working immediately and you can reuse it later for different projects.

The OMRON PLC has software which allows by simple drag and drop of ready functions (delays, logic, etc.) to build your desired schematic and to make everything you want.