A Tale of Two Browser PCB Tools

2015年8月22日 | By News | Filed in: News.

Source: http://hackaday.com/2015/08/21/a-tale-of-two-browser-pcb-tools/

We live in a golden age of free Electronic Design Automation (EDA) tools. It wasn’t that long ago that an engineering workstation was an expensive piece of hardware running very expensive software that typically had annual fees. Now, you can go to your local electronics store and buy a PC that would shame that old workstation and download plenty of software to design schematics, simulate circuits, program devices, and lay out PCBs.

The only problem with a lot of this free software is it runs on Windows. I do sometimes run Windows, but I most often use Linux, so there is a certain attractiveness to a new breed of tools that run in the Web browser. In particular, I wanted to look briefly at two Web-based EDA tools: EasyEDA and MeowCAD. Both offer similar features: draw a schematic, populate a PCB, and download manufacturing files (that is, Gerber files). EasyEDA also offers SPICE simulation.

There’s a lot of advantages: the software is always up to date. You can use it just about anywhere and have access to your files. Of course, there are some cons too: Many people don’t trust their designs in the hands of some alien server. There’s also the problem of what happens if the Web-based service pulls the plug.

This last is a particular problem. People have demonstrated they have a very low tolerance for paying for access to a Web site. Yet, it costs money to run a site, so how will the tool sustain itself? Each tool has a different answer to that question. EasyEDA has promised that if they were to shut down they would open source their code and also provide adequate time to download files. Of course, good intentions can always go wrong, but if they ever do shut down and can follow this plan, you could at least install the software on your own and keep going.

MeowCAD, on the other hand, is already open source. That means you could host it yourself now which would prevent you from worrying about them leaving and might also mitigate some privacy concerns.

So the choice is easy, right? Use MeowCAD (despite the silly name and the slightly annoying cat motif). Well, not so fast. If you try both, you will quickly see that EasyEDA is the more polished product. Even without the silly cat motif, EasyEDA works most like a traditional package. The SPICE simulation doesn’t interest me much (hard to beat LTSpice, even if I have to run it in Wine). But the rest of the package, the documentation, and the overall look and feel of the system is superior, in my opinion, to MeowCAD.

In either case, of course, you export Gerber files and schematic images, so you have some record of your design. EasyEDA will offer to create the boards for you (at a pretty low price, too). That’s how they plan to sustain the Web site is through profits from producing boards. However, they don’t prevent you from downloading all the files you need to take your design to any board manufacturer that you like.

I could do a review of either of these packages, and I might at some point in the future. However, since both are free, it is easy enough to just go try them yourself. Both sites also have video walk-throughs (see below) if you can’t bear to create a free account on both sites.

easyedaEasyEDA (left) looks and feels like a desktop application. It supports multilayer boards, and has simple design rule checking. It can generate 2D mockups of a board layout. There is a new symbol wizard (as well as an editor). Navigation functions let you cope with a complex board, even one spanning multiple schematic sheets.

About my only complaints have been that on a small screen the property editor panel hides, and I have spent time trying to remember that I have to pop it out to do certain tasks. Another minor issue is that it doesn’t seem to have a way to make wires have a certain attribute and then set their properties as a whole. For example, it would be nice to mark all power wires as class POWER and then make all nets of that class be 12 mils wide. In all fairness, you can access the tool’s XML representation, so you might be able to do something like that with a custom external tool.

meowcadMeowCAD’s work area is fine, although the menus and toolbars are not always as obvious (and mostly look like cats). The component library is hard to read on my monitor. Overall, the application feels more like a Web page and less like a desktop application. If there is an easy way to add custom symbols to the program, I couldn’t find it. Don’t get me wrong, it is impressive that MeowCAD has the features that it has. However, if you compare it to EasyEDA, it isn’t nearly as polished and usable.

heart

I haven’t produced a board with MeowCAD, but it seems adequate to the task. Their example board with heart-shaped outline (see left) looks good. I have, however, had EasyEDA build some boards for me. The boards (see below) look great and were very inexpensive (25 boards for about $22 plus modest shipping). Admittedly, this is a small board, but the pricing seems reasonable if you quote larger boards. Some roughly Arduino-sized two layer boards were $33 for 25 boards. Note these are not price per board, but the total price (excluding shipping). You can order as few as 5 boards although, as usual, the per piece price rises (5 of the larger boards were $18, so five times the number of boards for less than twice the price).

pcb1

Of course, if you want totally free design software, KiCAD is a good option (both of these tools borrow the KiCAD component libraries; MeowCAD can even export to KiCAD). There are also many other free options if you can stick to Windows or if you just want schematic drawing. However, for today, I wanted to stick to browser-based tools.

Although I think EasyEDA is more polished, both tools are usable and I applaud MeowCAD for being available in source form. Even if you choose to use the Web site, it is nice to know that you could always set up your own installation if you had to. I’m sure EasyEDA intends to stay around and also intends to honor its promise of how it would shut down if that were necessary. However, I know if things are actually going bad, it could be hard to keep that promise despite good intentions. For now, though, I’ll stick to using EasyEDA for some simple projects that aren’t very critical. The workflow is good and the convenience of basically clicking an order button and having the boards show up in the mail is hard to pass up.


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