I'm sorry, at the moment I don't have teaching materials in any presentable form. I tried Arduino-based projects, making parts of a 2D game in Swift+SpriteKit, fooling with Minecraft redstone, and worked through Google's blockly games.

Arduino seemed to be click the best, because it involves a lot of working with your hands (both breadboard and soldering) and you can "see" your creation working in a way that you just don't get with pure-software teaching. At least for the ages I was working with (8-10 y/o) blinking a LED held more joy than putting a 2D sprite into a window.

I thought about publishing a more formal project curriculum, but there's a ton of Arduino project books already on the market, so it didn't seem worth it. Instead I just pitch a couple ideas to the kids, see what they want to do, then we spend several sessions building that.