Oscar's control panel
This is a 3rd birthday present for one of my sons. It's his birthday today.
The unit is driven by a TI Stellaris Launchpad board (http://www.ti.com/ww/en/launchpad/stellaris_head.html?DCMP=stellaris-launchpad&HQS=stellaris-launchpad), powered by a Nokia BL-5J 1320mAH cell battery and charged by an Adafruit LiIon charger(http://www.adafruit.com/products/259). The front panel contains 26 LEDs and 11 DIs (4pos joystick, 3 buttons, 2 x 3pos switches). The LEDs all have a 47R resistor in series and are driven directly open drain. The DIs use internal pullups.
All the OR link resistors on the launchpad were removed to free up as much IO as possible. The direct USB +/- pins are used as IO. The direct USB port is filled with silicone to prevent accidental use.
The power switch is switched to take power from the direct USB port (set away from debug port). The 5V from the USB debug connector is fed to the input of the charger (from H19). The output of the charger and battery (in parallel) is fed to USB_VBUS (to H18), the input to the LDO regulator. The LDO regulator was not replaced with a switching regulator due to time contraints. U4, the power on reset control chip was removed as it is looking for 5V (the internal CPU reset is sufficient). The 3.7V min from the LiIon cell is sufficient for the LDO regulator to produce 3.3V output.
The panels were all drawn in sketchup and cut on the VHS laser cutter (http://vancouver.hackspace.ca).
The project is not remarkable except perhaps for the power circuit and the debounce pipeline in the code.