We hate to break it to [Rob Cai], but he’s built a VGA drawing toy, not an Etch-a-Sketch. How do we know? Simple, Etch-a-Sketch is a registered trademark. Regardless, his project shows how an Arduino can drive a VGA monitor using the VGAx library. Sure, you can only do four colors with a 120×60 resolution, but on the other hand, it requires almost no hardware other than the Arduino (you do need four resistors).
The hardware includes two pots and with the right firmware, it can also play pong, if you don’t want to give bent your artistic side. You can see videos of both the art toy and the pong game, below.
Because the device started as a pong game, [Rob’s] version has two boxes, each with a pot and a button. Of course, if you were really building it just for the drawing toy, you’d probably put it all in a box. Maybe even a red box. If we were building it, we’d be tempted to put a tilt sensor or an accelerometer in the box so you could shake it to erase the picture. Just saying.
If you want 640×480 resolution from an Arduino, it can be done, but it takes more hardware. If you were trying to get a kid interested in Arduino, you could do worse than start with two projects with video that are fun, use a handful of easy-to-source parts, and shares hardware. Then again, if you are in the “go big or go home” camp, we’d redirect to this pong game, instead.