The vm really needs to tell us what is trying to do when translating names to numbers, and probably needs to ask the image for help (not sure how to do that, but these defects are all too comon). I would have thought that either a symlink or using numbers (BTW, how does THAT work? <g>) would be enough.
Interesting about the parallel port. I have a book at home (IIRC, its The Robot Builder's Bonanza) that described using a particular type of buffer-driver chip to receive commands from a parallel port. I soon realized that quad or whatever prefix was irrelevant, and what was really going on was that the buffer-driver chip was able decode the parallel port lines (correct logic type) and the buffer business allowed it to give a little kick to things like relays. Bottom line: I had the parallel port switching relays that controlled electronic valves. It worked great. In the current world, I would probably drag out an AccesIO A/D board and use its digital outputs to do the work, but the chip did the job. Bill ________________________________________ From: [email protected] [[email protected]] on behalf of Pavel Krivanek [[email protected]] Sent: Thursday, March 22, 2012 10:52 AM To: [email protected] Subject: Re: [Pharo-project] Pharo and an old plotter The plotter needs only 6 pins (gnd, pen, axe, direction, step, ready) so it can be controlled directly via LPT. I firstly successfully tried a windows machine with a parallel port. For USB connection I used Arduino with serial communication where Arduino accepts simple basic commands and when it's done it sends a message to get the next ones. It's on Linux with latest CogVM but I had to create symlink from /dev/ttyUSB0 to /dev/ttySx and open the port by number (x), not by the name. See http://www.mail-archive.com/[email protected]/msg60816.html -- Pavel On Thu, Mar 22, 2012 at 2:56 PM, Schwab,Wilhelm K <[email protected]> wrote: > Nice! What is the physical/electrical connection? Serial, parallel, etc.? > If serial, did you have any problems with opening ports? On which VM? > > Bill > > > ________________________________________ > From: [email protected] > [[email protected]] on behalf of Pavel Krivanek > [[email protected]] > Sent: Thursday, March 22, 2012 9:47 AM > To: Pharo Development > Subject: [Pharo-project] Pharo and an old plotter > > Hi, > > I would like to mention one funny usage of Pharo. I have got an old > simple czech plotter from 1989 named XY4150. It is no secret that the > interactive environment of Smalltalk is ideal for controlling such > machines because it is very easy to send commands to it and experiment > with drawing capabilities. > > Even today such old hardware can find a real-life production > deployment. I currently use it to write owner names to plastic cards > with pre-printed bar codes by a special pen destined to sign credit > cards :-) > > It is controlled by Arduino however LPT can be used too. > > Btw. there was several interesting czech plotters. The most > interesting one was named Merkur Alfi. It was a construction set for > children with two stepper motors and one relay. > http://www.youtube.com/watch?v=yUmFYzyL9eo > > And they started to sell it recently again so if you are looking for > some cool hardware for your children, you can look here: > http://www.merkurtoys.cz/vyrobky/plotrovy-zapisovac-alfi-z-merkuru[1] > But it's about 139€ so it's quite expensive... > > Cheers, > -- Pavel >
