OT: Needing an LED changer circuit

[John Egerton]

Hi guys...

I'm revamping my midi foot controller and rather than just having a number display on the screen I'd like to have an led lit next to the last switch that was stepped on for eacy on-stage reference...

What i'd like is a circuit featuring 5 momentary switches and 5 leds...  When a switch is pressed, the corresponding led lights up until another switch is pressed and the active led changes to that one etc...

only one led can be active at any one time...

Does anyone have a circuit or suggestion that will help me accomplish this?

Thanks

John

[Sir H C]

This is like those controls for gameshows where only the first person can ring in.  

What I am thinking would be a bunch of SR latches, one for each button, where that button pulls the set for itself and then exercises the reset for all the others either with diodes or some other means.

[Peter Snowberg]

I do believe that R.G. has a circuit on GEO that will do just that.

IIRC, it was a latch chip with a little more circuitry to clock the latch when any of the inputs was made active by stomping.

[John Egerton]

thanks paul...

Do you have a link to that as I'm unsure what to look for on the geofex site...

Thanks again

John

[Nasse]

http://img.photobucket.com/albums/v411/Nasse/SETRESETw.jpg

This is old circuit from old Brasilian... oops just kiddin... from old Finnish magazine, set/reset latch cmos logig ic 4043B practical application, it is quite easy low parts count and works ok, and you can add more stages if needed. I think I made one switch default on state at power-on by connecting that "power-on cap" to one diodes junction.

Drawback is all stages get reset when any switch is operated (and the selected one gets selected because there is a cap at "set" input), but it does not matter in some applications :roll: .

I added transistors for leds (not shown) two resistors a transistor and an led per switch, values depend your supply voltage, transistors and led current.