First off I'll let you know my electronic knowledge is limited. (I have first year industrial electrician schooling) What i need is hard to explain but basically I have a xylphone type instrument and i want an LED to stay on for 2 seconds or so when a key is rung. i want an LED for each individual key. having a corded hammer (the thing you hit the keys with) is definiatly an option to carry voltage or whatever, and i need all this in as small as a space as possible. is this possible to be done easily and cheaply or even at all? please help.
it's definately possible, but i'm wondering the best way to do it.
I should think the best way is to have diodes on each key and a capacitor that charges on key press. Use maybe a darlington pair couple with the capacitor to act as a timing circuit.
personally i would use a 555 timer, but i can't think how you could isolocate each key with one single timer.
LED circuit help
Posted - Oct 14 2009 : 5:07:05 PM
