Aluminum foil is wrapped around a lightweight wooden panel which rests on a stand made from aluminum coil. When not in use, the three LEDs on the right side of the drawing panel are off. The pencil shown is connected to a 9v battery on the back of the panel.
Because the graphite inside the pencil is a conductor, the LEDs are illuminated by the act of drawing on the aluminum surface. When the tip of the pencil makes contact with the drawing surface, the circuit is completed.
The wire coming from the positive end of the battery is attached to the blunt end of the pencil with electrical tape.
The aluminum foil is taped to the back of the panel to hold it in place while drawing, but it can be removed and replaced with a new sheet if desired.
Three LEDs in series are soldered together and secured via small holes in the wooden panel. The positive end of the first LED makes contact with the aluminum sheet and is attached with electrical tape. The negative end of the third LED is connected to a wire which then makes contact with the negative end of the 9v battery.
Paul Zdon