My original LucidLights prototypes used Microchip controllers, 16 bright LEDs with LED driver chips interfaced via I2C, a 3-axis accelerometer, and two AA batteries in a 3D printed handle. Programmed in C, the orientation of the handle, and the sweeping direction (left-right or up-down) determined the graphics images or text messages to be displayed, with reversal of the LED patterns creating the same images in both directions. A momentary contact pushbutton allowed toggling through a long list of messages.
These prototypes had limitations, such as complex reprogramming of the messages, generally unsuitable for anybody but myself to accomplish. Also, the user is unable to see the current message being displayed.
I'm currently working on an updated model that will use Bluetooth or WiFi plus an Android phone or PC based app to design and upload the images and text messages. Rechargeable batteries are another goal.
Current experimentation is with an Arduino Nano RP2040 Connect board, although other boards might end up working better or be more cost-effective.