[ch00f] is at it again, expanding the horizons of the art of PCB business cards. This one draws his logo on any computer over a USB port.
The physical design of the card is heavily inspired by [Frank Zhao]‘s card; both use an ATtiny85 and the V-USB package to handle the USB protocol and communications. Instead of typing words into a text editor like [Frank]‘s, [ch00f]‘s card draws the ch00ftech logo in MS Paint or other image editor.
There was a problem with simply emulating the mouse to draw a logo on the screen, though; because different computers have different mouse settings for acceleration, the ch00ftech logo was nearly always distorted. [ch00f] fixed that by emulating an absolute input device, basically turning his business card into a single-function pen tablet.
The logo was traced by hand and put into a few arrays in the firmware. Surprisingly, the logo didn’t take up much space – only 4k of the tiny85′s flash is used. There’s a lot more space for a more complicated drawing, but for now the simple ch00ftech logo (video after the break) will do.