Introduction: LED Etch-a-Sketch
My LED Etch-a-Sketch is my first fully completed electronics project. I'm using four 8x8 LED matrices to make a 16x16 LED matrix drawing surface. Two potentiometers allow user input for column and row movement, while two tilt switches clear the drawing surface when the device is shaken. An ATmega328p handles the ADC from the pots and the multiplexing and driving of the LED matrices. Each individual matrix is driven with a 74HC595 shift register and a ULN2803 Darlington Array. It's probably not the best way to do it, but I found matrix drivers to be expensive and this way worked. The device is powered by 2 AA batteries stepped up to 5V with Adafruit's Minty Boost board. Again, probably not the best choice but it worked. All the electronics are encased in a crude, red acrylic case. The pictures above show various stages in the prototyping stage to the assembly of the finished product.
While it may not be the prettiest or the most energy efficient, it's a fun little gadget that I learned a lot from making!