At 2002-11-11 01:29 -0800, Mikael wrote: >I think using serial port is my best option since the microcontroller i will >be using contains a rather nice uart for rs232 communication (either 68hc11 >or 16f870). > >My goal is to have a driver that can be accessed by any program such as >Aries (pcb router) from Proteus so I guess I am left with 2 choices. >Firstly, as Vitaliy Vasylskyy suggested, to write a kernel mode driver from >scratch or Secondly, as Matthias Mansfeld suggested to get my plotter to >recognise commands intended for a generic HP plotter (would this work on >serial?). > >I will elaborate more on my situation. >Essentially the idea is to build a hobbyist level plotter from scrap because >I don't have access to cheap printing facilities where I live. I do not need >incredibly high resolution, in fact, it might sound a bit 'slap happy' when >i say to the nearest 0.5mm or so should do. I managed to salvage a couple of >600dpi HP printers with identical horizontal drive systems (linear shaft >encoder with strong spec. dc motor) which i figure will suit although im >worried about the load on one of the motors if I use an XY system (i'll >figure this out). Maximum print size will sit around 200*200 or possibly >300*300 mm at the most. So basically the hardware (mechanical and >electronics) side are pretty free going, I can change my plan along the way >to suit my software, the question is which technique should I use to make my >life as easy as possible? > >I will look into the HPGL and HPGL/2 and look into the DDK from microsoft >over the next few days and see what I come up with. >Many thanks to everybody who has replied so far, you have all been a big >help! >..more suggestions definitely welcome!
You should consider that making a precise plotter is much harder than making an precise printer. The problem with plotters is that when the paper is moved say 10 cm in the paper transport direction and back again, the head will not come back at exactly the same spot relative to the paper. That is due to friction between the paper and the rubbers of the transportation mechanism. And when you travel 10 cm up and down several times this error will get bigger and bigger until at a certain point the error will become untolerable. With the current cheap memory it's much better to draw the whole image in memory first and then print it out line for line, which is much easier to do accurately. Another problem is the pen. Whenever the pen stops drawing during the process of drawing a large picture it is usually necessary to redraw the whole picture, because it's very hard to regenerate the exact error position during the passage that the pen failed. What we used to do in the 1980's was draw the complete picture (in HPGL) to a file with the data for each line on a single text line, so something like: "PD;LI 100,100,100,200;PU" and then use the Unix sort application to sort the whole file. That would restrict the Y-movement of the paper a lot and therefore limit the distance that the paper would move in the paper-transportation direction. Or are you going to build a flat-bed plotter? ;-) That has the drawback that you need some sort of heavy bridge that moves in the Y-direction and due to it's inertia the drawing process will go much slower. I think you'd better save for a good printer... I saw a nice A0 or A1 printer from HP advertised lately for only around 1200 EUR. The A3 plotter that we used around 1984 did cost about 7500 EUR. (I think it was a model 7550). Here they sell second hand HP plotters: http://www.bidservice.com/searchsite/Browses/browse_test.asp?keywords=plotter Greetings, Jaap -- Chip Directory -- http://www.chipdir.biz/ -- http://www.chipdir.info/ -- http://www.chipdir.net/ -- http://www.chipdir.nl/ -- http://www.chipdir.org/ -- And about 30 other mirror sites world-wide. -- -- To subscribe to a free 'chip issues, questions and answers' -- mailing list, send a message to [EMAIL PROTECTED] with -- in the body 'subscribe chipdir-L'. About 500 experts are -- willing to think with you about electronics problems etc. -- Author: Jaap van Ganswijk INET: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB CHIPDIR-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
