There is no better way to learn electronics than building your own things. We have already covered plenty of apps that get you familiar with Raspberry Pi, Arduino, and other platforms. Adafruit has published a guide that shows you how to build your own 3D Printed Energy Sword with Bluetooth. You will have to use an Adafruit Feather BLE 32u4 micro-controller, a 2000 mAh battery, and a few other parts to get started.
The Adafruit Bluefruit LE Connect app lets you change the animation or color of the LEDs. The above video covers how this sword works. More instructions are available here.