Thread: Controlling Button LEDs

Depending on the keyboard, you may find running a couple of wires to the contacts under a keyboard will not work. A number of keyboards use magnetic switch. There is only a moentary pulse for each key pressed and one when it is released. If you hold a key down you dont have completed circuit like you would with a normal push button. If you want to listen to and talk to a keyboard you might be better of doing it from the ps/2 port side. ps/2 port is just a serial port at TTL level. Listen for the keypress. The LED can be controlled from the ps/2 serial stream as well.

Originally posted by Huge
Thanks for the Farnell codes but what's the difference in them?

The first 2 are red and green leds as are the second two codes?

Is there a difference?

When looking at the parts on farnell look at the Manufacturer part number. The part number that ends in 001 is the switch type with the light in the middle of the switch and the one that ends in 002 has the "ring" of light in the switch.

Nah, all of the codes for Farnell I listed above are for MPI002, the ring of light version.

Originally posted by phil.45
Nah, all of the codes for Farnell I listed above are for MPI002, the ring of light version.

I stand corrected.

Possible screw up on the web site?

Originally posted by Defiler
I stand corrected.

Possible screw up on the web site?

I dont think so.... They have different mnf codes. I suspect maybe the other pair doesnt have seperate LED terminals.

Originally posted by thenominous
If only that where true! If you check the US price's and then the UK prices for the same stuff, the rate is more like:

£1 <= $1

Dave

Unfortunately when buying from the UK they still think 1 USD = .69 UKP

I guess it's a lose lose situation for us, eh?