Electrical schematic drawing software

[Birdseyeview]

Does anyone know of a good free (or relatively cheap) software download that can be used on a MAC to draw electrical schematics. My Kitfox electrical schematic so far has been done by hand but it's messy and could use a cleanup. The standard schematic that came with my 2001 build manual was a good starting point but proved to be inadequate and incomplete so I had to redo it.

[PapuaPilot]

I was wondering the same thing and am not aware of anything for Mac. I ended up using Paintbrush which is fairly easy to make blocks, lines, circles and text and this app comes with Mac and Windows.

I just installed autopilot servos and made a schematic for that system. I copied a section of the closest schematic from the Garmin installation manual and edited it in Paintbrush. All I needed to do was to select sections & dragging them around, delete unneeded stuff, and adding a few additional lines, ground symbol and text. This took about 10 minutes in Paintbrush.


24358

[Birdseyeview]

Phil,
Thanks for the input - I used to have Paintbrush on my Mac and somewhere along the way it disappeared. But it's back now and it looks like it will do what I need it to do. Thanks again.

[n85ae]

Not the answer you're after, but ...

I used Graph paper with a pencil and paper, took less time than to install the software to use on the
computer :) After I built the plane, I have never even need to look at the sketch, since everything
I have ever needed to fix was pretty simple.

Jeff

[Birdseyeview]

Graph paper isn't a bad idea and I agree that once built and flying the schematics are only there for reference and hopefully won't get used that often. Like a lot of things on this project one has to weigh the time spent versus the possible payback. I like to review things multiple times and a redraw of some of my schematics should give me that opportunity. Thanks for the suggestion but in the end I like good looking documents and I have plenty of time lately. If the Paintbrush idea doesn't work out I'll try your graph paper idea.

[Delta Whisky]

Larry, et al, I don't know if my input will be worth anything but - just in case - here goes.

I too thought that a schematic was the way to go so I tried to use my 2D software of choice to do so. That worked well until I ran into the problem of understanding all of the combinations and permutations of integrating the schematics that came with my equipment of choice and my hoped for system schematic. I thought that that approach would save time and be a historical archive of some need if not note.

As it turned out (for me) the most important decision I made was to label each end of each wire that I connected by just taking one wire at a time. So, one wire at a time, I made notes on the schematics that came with the equipment to keep track of where the serial outs went to the serial ins. Not as easy as one might expect due to constraints you might find in the text that came with your equipment - for just one example, some ports might want to work best at different speeds. Also, not every serial out or in needs a sister in or out. Of course this process will work if done on paper (CAD?) prior to wiring but then you have inserted a step that need not have necessarily been done. So what am I left with? A partially completed paper schematic that I didn't use and, in its stead, a well annotated stack of installation instructions representing each piece of installed equipment. And - wires with labels on each end. (Except for some of the ones done late at night in which I forgot that critical step in the process AND have regretted it a couple of times).

Bottom line for me: All of the thinking that one will need to do won't supplant the need to carefully execute: pin 8 on the A connector of component 1 still needs to go to pin 11 on the B connector of component 3.

HTH and good luck in whatever you do.

[Birdseyeview]

Delta Whiskey
Good points all - Like you I would echo the importance of labeling both ends of each wire. I suspect this is actually a critical step and a drawing schematic alone won't necessarily replace this step.

I still like good schematics because in my case there are multiple ones and they have all been helpful in developing my understanding of how everything works together. I'm going old school with steam gauges in the cockpit so my wiring is simple by comparison to some. I had an advantage of working around aircraft systems wiring schematics for some of my career so I can state from experience that understanding how it all goes together is key and the schematics and wire labeling greatly support that understanding. I took my time and also thought about how the wiring harnesses should be bundled, routed and secured along their runs. I've tested most of the wiring so far and it checks out. Time spent on details up front pays off in the end although I still have my fingers crossed that some little error didn't sneak in somewhere. Looking back I recall many phone calls to various gauge and sensor suppliers to get clarification on their wiring and interface details. I was originally apprehensive about the whole wiring job because my 2001 build manual schematic had so many items left out or changed over time but it turned out to be a fun and satisfying task in the end. I did have to create some new schematics up front (by hand on paper) to accurately reflect my specific configuration. Another thing that helped was to have my schematic laid out roughly in the same physical orientation as the actual hardware (as much as possible that is). So the engine sensors and wiring was at the top of the schematic with items located accordingly on the left and right sides. The fuse box and ground terminals were in the middle, along with the various gauges and the panel switches are all at the bottom, all as if I was looking down on the plane from above. The gauges and switches were in left to right order as in the panel. This also helped me keep things straight, both in my head and on the plane. At each step along the way I got valuable inputs from many on this forum.

I also have a Challenger 2 that I didn't build and the wiring schematic that came with it is barely adequate, not very accurate or up to date, and there is no wire labeling. Although its wiring is dead simple in comparison to the Kitfox it can be a nightmare to troubleshoot. Sorry if I'm boring you all with my rambling on but like many of you these days I'm at home and working on my plane all my waking hours (not all bad).

By the way, I don't believe that a schematic has to be done on a computer as long as it's readable. On paper drawn by hand works just fine.

[hairy_kiwi]

Hi Larry,

Speaking from experience - as an avionics tech 20 years ago - and having completely rewired a couple of homebuilts and provided both owners with reasonably thorough wiring diagram documentation:

Least favoured option
First project was a Long-EZ in the early 2000's for which I used Bob Nuckolls' AutoCAD component libraries. The diagrams looked good, but, there was a ton of midnight oil burnt to go from zero to tidy, respectable custom drawing package while still finding time to do the actual ever evolving job. I haven't checked recently but the components/example drawings still seem to be available here: http://www.aeroelectric.com/Downloads.html

I notice Bob recommends TurboCAD, available from less than $100, here: https://www.turbocad.com/content/turbocad-mac - I have no experience with TurboCAD so can't comment on it. Otherwise, I'd probably suggest starting with this Mac CAD software roundup/review from September 2019: https://blog.capterra.com/8-of-the-best-cad-software-for-mac/


Recommended option - not (yet) perfect but a free open source option, with highly capable community support for project assistance and development of the software itself
After using KiCad https://kicad-pcb.org/download/ (free and available for PC, Mac, Linux) to design a small electronics PCB back in 2012, I'd always wondered if its schematic diagramming tool, Eeschema, was up to the task as an aircraft electrical wiring diagram tool. A couple of years ago, a friend's Jabiru SP470 needed a complete rewire, so it seemed like the perfect opportunity to put KiCad Eeschema to the test.

A bit of effort was required to extend Eeshema's electrical component library with aircraft style bus bars, contactors, knife edge connectors, an automotive style voltage regulator, etc - but the biggest issue, keeping track of wire idents was, and is handled very capably, by adding a wire 'pseudo-component' between interconnected aircraft components in the diagram. Compare the native editing colour and mono versions output plots of the same diagram:
Jabiru SP470 Wiring Diagram (colour)
(https://www.dropbox.com/s/5f37czsqweo4qiw/G-CBKY%20Wiring%20Diagram%20RevP%202018-07-12%20%28colour%29.pdf?dl=1)Jabiru SP470 Wiring Diagram (mono) (https://www.dropbox.com/s/98jchoxs43zcqol/G-CBKY%20Wiring%20Diagram%20RevP%202018-07-12%20%28mono%29.pdf?dl=1)

These pseudo-components are not an ideal solution, but they're still quite manageable. They offer a few nice features (over an un-idented, normal KiCad schematic 'dumb' wire between two real-world components), For example: wire names can be prefixed with a wire group or function code, or wires can be manually (re)named - say where you want positive and instantly human readable identification of a wire - before or after letting Eeschema generate wire names, where any old sequential number will do as long as its not duplicated. Or all wire names could be manually named and the built-in netlist function could be used to check you hadn't duplicated any.

Eeschema also allows quite a bit of intelligence to be imbedded in a wiring diagram too: Its very easy to include component names, part numbers, alternative part numbers, suppliers, etc, in the highly extensible data fields available within any component - including wire as a pseudo-component.

Feel free to download my entire Jabiru project package and play with it in KiCad Eeschema:
KiCad Aircraft Wiring Diagram package example - for a Jabiru SP470 rewired 2018.zip
(https://www.dropbox.com/s/qqj4vhrfpb7lu2g/KiCad%20Aircraft%20Wiring%20Diagram%20package%20ex ample%20-%20for%20a%20Jabiru%20SP470%20rewired%202018.zip?d l=1)The primary file you're interested in is the one ending .sch - its not a complete aircraft wire diagramming ecosystem, but I feel its a good start.
Just note the terms of the (very permissive) MIT License (https://opensource.org/licenses/MIT) included in the zip file. It needs to accompany any work(s) derived from the content of this zip package, ideally with the license updated to display the latest author's name and copyright date before any further redistribution.

There is a bit of a learning curve, so some of these tutorials might be helpful: https://www.kicad-pcb.org/help/tutorials/

Hope it helps!

Cheers,
Jim
(https://www.dropbox.com/s/5f37czsqweo4qiw/G-CBKY%20Wiring%20Diagram%20RevP%202018-07-12%20%28colour%29.pdf?dl=1)

[jmodguy]

If you are an EAA member you can download a student edition for free and it includes electrical dog tools!

[Birdseyeview]

Jeff - The free software through EAA is SOLIDWORKS and it doesn't work well (and sometimes not at all) on a MAC, which is what I have.

[jmodguy]

Oops! Yup it is Solidworks and it is not made for Macs. Works on my Win 10 machine👍

[Birdseyeview]

When I was working I taught myself and used CAD often but I loved Microsoft VISIO better for 2D drawings. I could quickly draw just about anything on that software and electrical wiring interconnect diagrams were a breeze to create. I had access to large format printers and drawings were fun to create, and they looked great. Although I was used to all the MS office products, after I retired I switched over to Apple and bought a CD copy of MSOffice that ran on a MAC. VISIO was too expensive, or I was too cheap at the time, and I no longer had a large format printer. My options became more limited.

Although I have created all my electrical wiring drawings the old fashioned way, I've been very impressed with some of our Kitfox builders and their impressive CAD type drawings. Thats what led to my initial question about what software might be available. I've since looked at and studied a few of the suggested options until my brain hurts and I've come to the conclusion that without a big format printer for me right now the old fashioned way is just fine. Those of you that have access to all the latest computer software and printer should consider yourself as blessed. Thanks all for your good suggestions but I've come full circle in my thinking about this topic and my table below with its large format paper is still pretty effective. My eraser still works fine and the thin lead mechanical pencils now days never need sharpening. My old fashioned method also never needs a software update or a monthly subscription fee. A photo of my main schematic is included, which still needs a little touch up here and here.

2440424403 I bought my drafting table and drafting machine 25 years ago at a high school auction for less that $20. Thats a hard one to beat.

[byteworks]

Eagle (https://www.autodesk.com/products/eagle/free-download) - has a free version available.

[Delta Whisky]

Birdseyeview - Your drafting table brings back great memories of days gone by. It sure is easier to see "the big picture" that way and offers a lot of personal enjoyment.

In catching up on this post I see that I never answered your first question. I use Draftsight as my CAD program. It used to be free but they now charge a fairly reasonable fee. I got so hooked on it that I decided to pay the tariff as it makes my life much easier and I'm too lazy to learn another (free) program. I use it a lot to lay out parts, glue the paper to flat stock and start drilling and cutting. You can't beat the speed, accuracy and ability to make changes if the first version doesn't work out quite right. If I need to print out something full size that won't fit on a piece of letter size paper, it is off to Staples or Office Max for a reasonable fee. You already knew these benefits but this gives me something else to do during lock down (waiting for the next ACS delivery) and others that are sitting on the CAD fence might be encouraged to take the step.