Thanks for the offer. I ordered the stock items with the 16 IO stamp so I
can write and debug the program while down here. I have one of the four DC
gear motor units running. Should keep me busy for a few months.
Roger, if you're at all interested, the best board to use is the G4PB32DEC
from Opto 22.
There's a data sheet page there that gives the pin outs to the 50 pin
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.
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.
I asked the same questions on another NG. Best suggestion was to use this
Parallax also sells a USB port to stamp module. It has the prints so you
could copy it if desired.
It has basic stamp source code examples to add up to 64 outs to a stamp.
I just thought of an idea that might work for Basic Stamp users and PIC
microcontrollers. Make a board with an Opto22 compatible 50 pin header
connected to a PIC microcontroller. Have the board ship with a program in
the PIC to receive serial I/O from the Basic Stamp (or any other controller,
or even a PC) so the Stamp would use 2 pins and be able to control up to 32
Opto22 I/O. Or, the user could write thier own control program in the PIC
if they had an in circuit serial programmer. I would like to use a PIC with
more I/O so a LCD display and keypad could be plugged in if desired.
Right on. AND I'll know how to do it right after I've done it the other way.
Plus, I've got a history of always looking down at the sparkies (EEs). Real
engineers always ran the project and delegated this work. My main function
was to ask, "why aren't you done yet?" and, "We need this additional
function". I guess this little job is payback.
On Wed, 06 Jan 2010 07:40:07 -0500, Karl Townsend wrote:
Karl, if your sorting puts EE's and "real" engineers in disjoint sets I'm
not sure that I like you any more.
What sort of engineer is "real" to you, and what traumatic experience did
you have in your youth at the hands of an EE?
I've been doing some work on using a PIC microcontroller to send and receive
serial data to work with Opto22 boards. So far what I'm working on is
compatible with the 50 pin header boards from 8 I/O to 24 I/O, the 32 I/O
board has a different pinout on its header. I think I can read/write the 24
I/O points, plus communication, plus have an in circuit programming and
debugging port, all with a 40 pin PIC microcontroller.
I plan to have the PIC preprogrammed as a serial I/O board to work with
Basic Stamps, PC's or whatever else has a serial port. Most of what I've
done so far has to do with the schematic and board layout, connector
pinouts, and hardware for the project. I'm far enough along now with
hardware design that I need to build a prototype on a breadboard and start
developing and testing the software.
This board should be addressable either in hardware or software, meaning 2
pins from the Basic Stamp could be used for 24, 48, 72, 96,... I/O points,
you could have 6,144 I/O points with an 8 bit address and 24 I/O per module,
but the update wouldn't be very fast ;-)
And.. The PIC microcontroller on this I/O expander board would be
programmable to turn the Opto22 board into a stand alone PLC type
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