This is the magic lights circuit which use bi-colour LED as the output to provide the light. The circuit uses 14 bi-colour (red and green) LEDs having 3 terminals each. Various dancing colour patterns are generated utilizing this circuit considering that each LED can create three various colours. The middle terminal (pin 2) of the LEDs will be the common cathode pin that is grounded. When a positive voltage is applied to pin one, it emits red light. Similarly, when positive voltage is applied to pin 3. it emits green light. And when positive voltage is simultaneously applied to its pins 1 and 3, it emits amber light.
The circuit could be implemented for decorative lights. The IC1 (timer IC 555) is applied in astable mode of multivibrator to produce clock signal for IC2 and IC3 (CD4518) that are dual BCD counters.
The two counters of each one of these ICs have already been cascaded to acquire 8 outputs from each. The outputs from IC2 and IC3 are connected to IC4 through IC7 that are BCD to 7-segment latch/decoder/driver ICs. Therefore we acquire a complete of 14 segment outputs from each of the IC pairs composed of IC4 plus IC5 and IC6 plus IC7. While outputs from former pair are connected to pin No. 1 of all the 14 bi-colour LEDs through current limiting resistors, the ouputs of the latter pair are similarly connected to pin No.3 of all the bi-colour LEDs to acquire a magical dancing lights effect.