Congratulations on your skillset. You sound like a true multipotentialite, I’m impressed!
Here are my 2 cents:
First of all, be super vigilant about how much time you spend on projects. Time is the most valuable thing you have, and it’s a finite supply. So track how many hours you spend on a project, do a quick off the cuff estimate of how much you think you’re going to earn, and calculate a very rough hourly rate.
If the rate sucks, don’t do the project. Or treat it purely as a learning experience. From now on, each project competes with spending time with your kid.
Second — promote yourself as much as you can. Talk about your projects on multiple channels and in several media formats. Here’s an example:
You mentioned you built a smartwatch? Great! Write a short howto document about the project. Now film yourself reading the howto and going through the code. Put that video on Youtube. Create a Youtube channel. Polish your Twitter, Facebook, and Linkedin profiles while you’re at it. In the Youtube video, tell everyone they can email you for the source code. Collect all emails in a list, and send a nice reply with the code to everyone. Now write a blogpost about your greatest challenge in the project. Put the post on Medium. Try to get noticed by one of the big Medium publishers. Don’t forget to notify everyone on your list about the post. Write a few more posts about the project. Film yourself talking about these posts and the code. Bundle the videos in a course (“how to build your own smartwatch in 7 days”). Sell the course on Udemy, and promote the course to your list. Now do a webinar, and promote the course at the end. Write a few more blog posts based on your videos, and bundle them in a book. Self-publish on Kindle and iOS.
You now have a super-valuable email list, a Youtube channel, a Medium publication, a book, and a course. Your monthly passive income should now be around $100-$300. Remember: this is passive income. You can move on to other projects and the income will continue.
Rinse and repeat for all your other projects.
Bonus points if one project builds on another. For example, if you use 3d-printing in more than one project, you can recycle the content.
Bottom line — your projects probably won’t generate a lot of money on their own, but you talking about your projects and showing others how to do the same is worth a lot of money.
One of my side projects (= teaching) took off and is now my main source of income. I do cool projects just like you, but I earn a living teaching others how to do the same. I make $10 per student, but I have a lot of students. It’s not a bad life…