Need help with latch/memory cell.

[gloowa]

Hi.

I'm trying to devise a kind of memory cell/latch (different from S-R).

What i need it to do is as following:

When it starts, it produces no output. When ANY type of input (it may be any type of item) is first introduced, it will serve that on the output immediatly, but will ignore any further inputs, or a disappearence of original input.

In essence, i want a memory cell that will remember the first type of item that it comes into contact with, and output that item and only that item forever from that point onward. The numeric value of the output doesn't count, just the type.

Is something like this possible?

[DaveMcW]

Filter: Red = 0 → Everything input count (Input wire: Lock)
Memory: Each + 0 → Each (Input wire: Filter, Memory)
Lock: Anything > 0 → Red 1 (Input wire: Memory)

[gloowa]

It works, thank you very much!