possible answer for relay switching

[j.frad]

I've been wanting to build a relay switchin system for a while and I remember one being posted here a while back but I can't find the thread anymore...
Anyway, that layout (maybe someone else could point to it)  was great because you could "program" a certain number banks(one per switch) via dipswitches that would activate different loops, but the problem was that to activate a "bank" you had to deactivate the previous one first, what I want is to be able to switch just like one the marshall TSL heads, switch1>channel1 / switch 2>channel 2 / switch3>channel3

Yesterday I just found this chip : http://www.elabinc.com/ede2108.pdf

which seemes to be great for that project because it does what I want , cant switch on up to 8 "banks" and only uses temprary shitches that are cheaper! but I have some concerns about the current draw of the circuits that turn on the relays. The max current output for each pin is 25mA, is that enough? Also, absolute max power supply is 5.5V, is it recommended to use a voltage regulator to power this chip?
Hope I'm useful!
Thanks a lot.
jules

[R.G.]

Well, I don't know what they're actually using, but the pinout and specifications look suspiciously like they've taken an eight pin midrange PIC or Atmel flash controller and just programmed it to watch pushbuttons and do an output. That's about a $2.00 chip.

Note that you can do the same thing with a $1.00 chip and some diodes, resistors and caps. See the programmable effects foot switch controllers at GEO.

[Gripp]

Perhaps it was this one?

http://www.diystompboxes.com/smfforum/index.php?topic=39449.0

http://www.generalguitargadgets.com/index.php?option=content&task=view&id=211&Itemid=236

I've been looking at it since it was released and must say that your chip find looks like an interesting approach.
The only real current that will be sunk from from the chip is that for the leds. I make it 23 mA in total with the 220 ohm resistors and a 5V supply, since only one would be on at any given time. Up those resistors a bit for safety perhaps and it would probably work. I'm no expert though.

On the other hand, RG is an expert and the economy argument is a strong one as well, could possibly be easier to graft on too.

Best!
Pelle G

[j.frad]

yes that's the thread I was thinking of!
I didn't find the programmable effects loop at Geo... But you're probably right RG, but the reason I talked about that chip is because I know nothing of microcontrollers pics and stuff like that and that chip was easy to understand: input/output/power can't make it easier!
oh well, maybe I'll try it some day, have to learn more first i guess!

[MetalGuy]

Very interesting chip!
Check out also R.G.'s article on that. There was a 3 and 4 way footswitch schematic on Aiken's but it's not there anymore.
This one looks like the easiest solution for now. Except via their web site do you know where else those chips can be found?

[d95err]

How much would this chip cost, and where can you get it?

Sure, a PIC costs perhaps $2, but you also need a PIC programmer (hardware) and more importantly - you have to program it. This chip would make things so much easier in terms of (no) programming, layout etc, it would definately be worth paying a bit extra.

[R.G.]

See illustration 7 here: http://geofex.com/Article_Folders/fxswitchr/fxswitchr.htm - from 1/18/00.

[MetalGuy]

The chip is available at Jameco and costs $5.99 the piece, which as R.G. already said is most probably a preprogrammed microcontroller, which means there's no need for programming.

[R.G.]

I think I'm doing myself a disservice. I guess I should be thinking of all the obvious things to do with a PIC and selling $1(in quantity) PICs for $6.

The >whack<ing sound you hear is me slapping myself on the forehead.