It works well, at the moment rather than hanging a relay off it I have a little green LED on a bit of wire, just to test before I buy the $12 AUS solid state relay..
One problem I have found, is that the circuit responds to 2 sharp claps. Now that part is ok... sort of. If say I were to clap now, then wait 10 seconds, and clap again, it triggers the circuit and the LED goes on/off. What would be interesting to know is:
a) Is this circuit supposed to only respond for a certain time (i.e I've wired something wrong)
- and if not -
b) Can I put something in to make it only respond for 250-500 milliseconds after the first clap?
Yes there is. See the schematic below. With the values shown, you can limit the range from approximately 100ms to 1 second. To increase the range, make C4 larger.
BTW, if values are not shown explicitly, they still have the values from the original schematic.
Edit: Added a toggle flip-flop (IC5), which I forgot in the original schematic.