Arduino is a great starting point for electronics, and with a motor shield it can also be a nice tidy platform for robotics and mechatronics. Here is a design for a full-featured motor shield that will be able to power many simple to medium-complexity projects. Build the kit, and learn how to use it with these detailed instructions.
You can wire arcade buttons to the Gemma M0 which can be programmed in CircuitPython as a USB HID device (emulating keyboard strokes) to control any iCade compatible game on iOS! Plus, you can build your own stylish, rugged mini table using slotted aluminum extrusions and hardware! And, no soldering is required, just plug and play!
Build and code a radio communication system that notifies you of incoming messages, for example via automated puppet, and then displays the message on the Micro:Bit LED screen. No prior experience coding or using hardware is necessary. But! As this project involves communication (a two-way street), it’s a project for two or more people. Grab a friend, a micro:bit each, and build it together! Yayy collaboration! :D
The Basic String Car is a simple project that consists of a battery, motor, pulley, and a bit of fence wire. The initial design of the car was made from repurposed parts and materials found in Grandpa's basement workshop. This version uses some commercially-available parts, but could be hacked with parts gleaned from old CD players, for example. What modifications and improvements would you make?
The PiUART adds a MicroUSB to serial connection so you can use any serial port software to connect to the Pi's console. It plugs in and is fast and easy to add whenever you need to connect to your Pi. You can power your Pi through the microUSB port and then use the switch whenever you want to cut power, without having to unplug the cable.