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

[WannabeGT4]

LOL. honestly I get lost in all the binary logic going on with the NAND, NOR, and all the other gates and flip flops... after I typed all that up I started looking into micro controllers.

I found one that is extremely simple to work with. It's called PICAXE and uses a BASIC style programing language. I guess it's used a lot in schools for beginners... which I am. I think I can get it to work after a little refresher in BASIC programing. I'm downloading a simulator now so I can write my own code and see if I can't get it to do what I want... I may even have enough outputs on the PIC to make it light an LED matrix that I can use to display alpha numeric characters.

If you have a different suggestion for micro controllers I'm all ears but I have very little knowledge of any of the more advanced programing languages.

[Mangozac]

LOL. honestly I get lost in all the binary logic going on with the NAND, NOR, and all the other gates and flip flops... after I typed all that up I started looking into micro controllers.

I found one that is extremely simple to work with. It's called PICAXE and uses a BASIC style programing language. I guess it's used a lot in schools for beginners... which I am. I think I can get it to work after a little refresher in BASIC programing. I'm downloading a simulator now so I can write my own code and see if I can't get it to do what I want... I may even have enough outputs on the PIC to make it light an LED matrix that I can use to display alpha numeric characters.

If you have a different suggestion for micro controllers I'm all ears but I have very little knowledge of any of the more advanced programing languages.

Heh I haven't done anything fancy with gates in a long time. There's not much point when you can use a microcontroller.

Actually, I'd recommend sticking with the PICAXEs. I played with them ages ago. They are very simple, but perfect for the sort of thing you want to do!

I program PIC microcontrollers in assembly, which is free but also a LOT harder than BASIC! I'm sure the bigger PICAXES could do the matrix thing you're talking about.

If you have any other questions or issues or need more advice feel free to email me!