"Karl Townsend" wrote in message
anews.com...

If it were me I would probably use a $3 PIC microcontroller with 36 I/O
such
as the PIC 16F887.

http://search.digikey.com/scripts/Dk...C16F887-I/P-ND

But I already have most of the associated tools I need including a
PicBasic Pro compiler, a PIC C compiler, and a PicStart Plus programmer.

If I can find out about the sockets that Opto22 type SSR's and input
modules take, it would be nice to lay out a board that you can put a
microcontroller, voltage regulator, and sockets for 32 opto isolated I/O
modules.



Roger, if you're at all interested, the best board to use is the G4PB32DEC
from Opto 22.
http://www.opto22.com/site/pr_detail...item=G4PB32DEC
There's a data sheet page there that gives the pin outs to the 50 pin
header.

I got tired of buying these boards at $10 each on eBay. I must have a
dozen. G4 series IO go for about $1.50 each on eBay

I know the outs fire by pulling the (5 volt) TTL pin to gound. Easy to
test with just a jumper wire to ground. The ins show TTL plus (red) on the
logic probe when active, TTL minus (green) when off. These boards and IO
are designed to work with a PC IO card. The Contec PIO 16/16T being a very
common one. I use this set up on all my CNC machines

I'm kind of surprised someone isn't selling a micro controller module that
just plugs into the Opto 22 header. You'd have a powerful unit for
peanuts.

Karl

I think it would be an interesting project to make a board that connected a
microcontroller to that Opto22 board. I've also been looking at bus
transceivers, latches, and multiplexers. I'll have to order some chips to
experiment but it might be easy to get 32 (or more) I/O from a BS2. The
idea is that you have multiple 8 bit chips, some for input, some for output,
the 74XX138 selects to enable 1 of 8 chips based on the binary address
inputs. The outputs latch what the BS2 outputs, the inputs enable to read
that selected input. The program would do something like read the inputs,
process the logic, write to the outputs. There is an output enable on the
latches so you can turn them all off at once if desired.

I've been interested in investing some money in a project this year to try
to see if I can make it grow, Basic Stamp and MicroController to Opto22
boards might be an interesting investment. I would like to see what's
required for in circuit serial programming(ICSP) so users could program from
the USB port. I'd also want the Basic Stamp to be programmable without
removing from the board.

RogerN