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Changing Your Image. . . Software by Herman Nacinovich Do you make or design your own PC boards? Here are two utilities which will let you reverse Protel files or PCL files. Many hobbyists make their own PC boards, which is why SILICON CHIP not only publishes PCB patterns in the magazine but makes them available free of charge on the website (www. siliconchip.com.au). Some go one step further – they design their own boards as well. Once upon a time, this was a messy process involving drafting pens and clear film. Then tapes and pads came along making the process much simpler. Today, it’s even easier with a variety of computer programs to make PC board layout a breeze. You design your board, check it then print it onto a piece of film, then produce your board using conventional photo-resist and etchant techniques. It would appear that the vast majority of people designing PC boards use one of a variety of programs from Protel. And despite a big effort being made to “upgrade” users to Windows-based software, many are quite happy using the earlier DOSbased versions. Autotrax from Protel is perhaps the most popular, although the freeware version, Easytrax, is widely used by hobbyists. Despite these programs not having all the bells and whistles of their more recent counterparts, it seems a very large number of users are comfortable with the old versions and are happy to stay with them. (We speak from experience here: guess which software and version we use at SILICON CHIP?) One of the bells and whistles which the older versions of Protel lack is the ability to print negative images. When you have laid out your board, what you have is what you print (should that be WYHIWYP?) If you work in positive photo resist, that’s no problem. But a significant number of resists (either liquid form or pre-coated boards) are negative acting. Problem: DOS-based Protel cannot print negative. The printed image has to be converted photographically (and how many hobbyists have access to that sort of equipment?) It’s not only time consuming, it’s incovenient and it can be costly – possibly much more than the PC board is worth! Before we go any further, perhaps we should explain the difference between negative and positive images because they are often misunderstood. When talking about PC board patterns in particular, a positive image has black tracks and pads with clear or white holes and board background. Negative images are, as you would expect, reversed: white or clear tracks and pads with black background and holes. Now, back to the problem at hand: one of SILICON CHIP’s regular contributors, Herman Nacinovich, has written a program in QuickBasic (Left) A positive PCB board pattern, as produced by Protel's Autotrax. (Right) The same PC board pattern, reversed using convert.exe 78  Silicon Chip which will convert a Protel PCB image file from positive to negative format (or, indeed, vice versa) suitable for printing on an HP compatible laser printer. DOS Software The software (which is available on www.siliconchip.com.au) works with HP PCL format image files. Fortunately, most HP or HP compatible printers use this format. And while it has only been used with Protel-generated PCB files, it may work with images produced by other software as well. It will probably not work with compressed graphic files. The program is simple – in fact, the author points out it was written simply to do this particular job and while it works fine for him, there may be bugs which he hasn’t discovered yet. On the other hand, the price is right – it costs you the grand total of one phone call to your ISP! The DOS-based program is called convert.exe. Like most software on the ’net, it will be zipped up and require unzipping with PKUNZIP. Look for the software called CONVDOS.ZIP on the software downloads section of the website. Once downloaded and unzipped, the procedure is as follows: * Create the original image * Save the output to file rather    than printer Once set up, the Windows version of the software is very easy to use. Simply load the file you wish to convert, choose your options . . . and wait! * Convert the file using the   convert.exe utility * Print the converted file (using   DOS print) Windows Software And what of the readers who work in Windows? Don't worry, you haven't been forgotten. The same author has written a similar utility to convert any HP PCL file under Windows 3.x This program, also available from the SILICON CHIP website, actually does a little more: it gives you the NEW! option of printing to an HP laserjet (or compatible HP PCL printer) via either LPT1 or LPT2. It also gives you the option of printing to file and/or converting the file to either TIFF or RLE formats. All this is undertaken from the Windows screen in the familiar point'n'click manner, as demonstrated by the screen images below. A word of warning – it does take quite a long time (minutes on a slower machine) to convert the file. The progress bar shown in the righthand image takes a long, long time to System 90 multi-cell charging station for NiCd/NiMH cellular, two-way, notebook & video batteries for NiCd/NiMH cellular, two-way, notebook & video batteries SIMULTANEOUS CHARGING – of different type and capacity batteries. Adaptors available for over 600 different batteries! INCREASES LIFE – reduces overcharging and increases battery life by detecting the fully charged condition IMPROVES PERFORMANCE – ensures maximum recharge capacity by a controlled discharge to 1.0V per cell SAVES MONEY – extends life of old batteries by cycling to remove memory effect and improve capacity get through. At least, though, you can see where you are up to. On the website, the Windows version is a suite of programs called CONVWIN.ZIP, again requiring unzipping with PKUNZIP (we actually use PKZIP for Windows). Download the file, saving it to disk, unzip it (again saving the unzipped files to disk) then run the setup.exe file from the taskbar and everything is done for you. You have the option of accepting or changing the default directory into which the program is SC loaded on your hard disk. 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