If it isn't obvious by now, I have some experience building electronics and programming. I've never done the electronics side professionally, but I did graduate college with a BS in Computer Engineering. I've been programming for 30+ years.
While I've designed, etched, and built many simple circuit boards over the years, I've only ever had one, semi-complicated one sent out to be made. At the time, I used Eagle CAD for the schematic capture and board layout functions. I remember fighting with it a lot. I wanted to use something different this time. After searching around I decided to try out KiCad, a free, cross platform, open source design suite. A quick download and install, and I'm off and running.
I've been at it for about a week now. Like any serious piece of software, there's a learning curve and the same goes for KiCad. But it hasn't left any scars. There's a quick start tutorial provided and I was drawing my schematic and building my own schematic symbols on the first day. I've moved on to a hierarchical schematic now which splits up the design into more easily digestible pieces. I'm still designing some of the input conditioning portions and I have to revisit the power supply area once I get all the other parts added. I haven't yet started any board layout and that's where I expect I'll start having problems, if there are any to be had. All-in-all, KiCad has been great. I'm learning the keyboard shortcuts and quirks and getting faster every day.
Besides simply getting a design in my head out on paper, one of the most tedious and time consuming parts of this process, at least for me anyway, is parts selection. Many of the parts are obvious, but there are enough unknowns that slogging through datasheets to find the parts with just the right parameters is draining. I'm glad I don't have to do this for a living. There are many nights I go to bed frustrated at being unable to decide between two parts that fulfil the same purpose but whose ratings are slightly different. In those cases, I try to err on the side of caution and pick parts with larger margins, but that can come at a literally high price. Most of the components are cheap in the grand scheme of things, but since I'm trying to design for manufacturability in large quantities (if this project takes off), even a difference of a few cents can scale to thousands of dollars in a production run.
And don't even get me started on the cost of connectors. I'm leaving that for last. Believe it or not, connectors, plugs, sockets, etc. can eat up a huge portion of the cost of a piece of electronics. You'd think it would be the semiconductors like the MCU, but in my experience it's almost always the connectors that kill you. All those stupid, little, unprogrammable pieces of plastic and metal.
I will continue with the work and keep you posted.