Level up from Arduino by following this guide to build a Bluetooth light display. You'll use KiCAD for a custom PCB based on an nRF52 wireless module, Zephyr RTOS for the embedded Bluetooth, and Flutter to develop a cross-platform mobile app to control your wireless device.

This tiny fully featured BLE development board works great for prototyping IoT applications. It's not much larger than a production BLE module. I love it because you don't have to bother with soldering a USB-C connector (a huge pain). Plus you can get a few sensors out of the box to make your life easier.

I'm a huge fan of Pine64's soldering iron. I use it almost daily and it's a lightweight powerhouse. Quick to heat, portable, and affordable. I'm very happy with it and I love that it's open source. One thing to note: it is bring your own power supply, it does not ship with one. But with the fairly universal power ports, you probably already have a supply that works laying around.

This little gadget is very helpful when powering up a board for the first time. You donn't have to worry about frying one of your computer's USB ports. Great to use as a sanity check a new design, ensuring that it pulling SOME power but not too much. First line defense from letting the magic smoke out.

Cheap but indespinsble tool to keep an eye on what your board is doing. Wire it up to UART tx & rx pins to get a serial output on your embedded devices. Always have a few of these on hand.