up and down relay selector

[domenico]

Hi I need to build a circuit to control one a time 4 relays
let's say I have relay one , relay 2 , relay 3 and relay 4 , now I need to select them from relay 1 to 4 with 2 push buttons so I can go for example from relay 1 to relay 2 using the up button and from relay 2 to 1 using the down button and so on .
I need a circuit similar to geofex's one which uses cd40373 but controlling it with only 2 buttons
any suggestion ? thanks !
domenico

[R.G.]

The essence of the footswitcher is that you have to generate a logic signal to tell which relay to turn on and off.

The '373 switcher is a one-of-eight selector. You're looking for an up-down counter. The CD40193/74C193 is a binary up/down counter with up-clock and down-clock inputs. It puts out a binary word that then needs to be decoded to one-of-four (four in your case, could be more). The CD4028 and 74C138 do that.

So you hook up two footswitches to provide clock ticks to a '193, one for up, one for down. For four outputs, you hook up the two lower order bits of the counter to a decoder chip's low order inputs, and then take the desired signal off the lowest four bits of the decoder. That then drives your relays.

[domenico]

thanx thanx thanx thanx thanx !!!
domenico