Electrical Engineers?, I have some questions for you. Options

[WannabeGT4]

If you're an electrical engineer with knowledge of logic gates, e.g. latches and flip flops, I have a few questions.

I would like to build a sequencer with 4 outputs. One momentary switch will control the up sequence and a separate switch will control the down sequence.

For example, I have four lights. At startup, light number one will be on. I push the 1st momentary button and light one goes off as light two comes on, push the button again light two goes of as three comes on... etc.

The second button needs to be able to go backwards at any time, i.e. not having to go all the way up to 4 in order to go back down from 3 to 2 or from 2 to 1. The same should apply to the first switch as well. I shouldn't have to count down to 1 in order to go up from 2 to 3 or from 3 to 4.

This diagram is as far as I got. If the two transistors and logic functions could be integrated onto a single chip that'd be great but if not it isn't a big deal.



I've probably got something backwards in that picture but my brain hurts from trying to figure this out so I'm just gonna post this and see if anyone has any ideas.

[Mangozac]

I think I understand what you're trying to do in your diagram but it's a bit wierd - I don't think it will work.

I was hoping it could be done with one IC but it doesn't look like it. Not in 7400 series logic anyway.

So the way I'd probably do it (well, if I wasn't going to use a microcontroller ) would be with a 74HC190 and 74HC238. It actually turns out to be quite a pain to count up and down like that, or at least when there's only 4 outputs. On second thoughts you may need another IC....

I'll go away and have another think about it. I'm sure there's a novel way to do it.

Oh and I believe the correct title is electronics engineer!

This post has been edited by Mangozac: May 20, 2007 - 2:31 AM