Schematic for a kid's busy box meant to illustrate the combinations of primary colors. Aqua LED next to SPDT indicates the circuit in use (A or B) and represents real-world white. Blended colors are lit using NPN transistors as a logical AND. Each switch can have a different tactile feel (e.g. rocker, post, knob, push button, pull chain, slide, etc.) and switching function (e.g. toggle, momentary, position). Momentary switches can be either normally closed or open. A potentiometer was added to a single LED for dimming. The timer circuit between the 9V battery and ground is initiated by the "Go" push button and will fade out after about 10-15 seconds until the capacitor is discharged (depending on capacitor and resistor values used). There is also a "Stop" button which will drain the capacitor immediately.
(NOTE: LED and resistor values updated after a test build. Previous values prevented transistors from reaching the cut-off threshold, resulting in multiple LEDs shining when a single switch was used.)