The LED Christmas - Bell with 77 LEDs is a beautiful animated bell that will add a little festive cheer. Operates on 12V, for use in cars, trucks.
The circuit is based on the famous 555 timer. The 555 timer is wired as an astable multivibrator, and oscillates at about 1Ηz. The frequency of the oscillator can be adjusted micro-metrically from a variable trimmer resistor (R9).
The electronic circuit is extremely simple and can be easily assembled on the specific Printed Circuit Board, which is given below.
We use typical 5mm round LEDs. The prototype uses 66 yellow LEDs, 3 green LEDs for D11, D12, D13 and 8 red LEDs for D42, D43, D44, D45, D74, D75, D76, and D77.
Placing the components on the PCB and building the circuit is easy enough, if you follow the instructions given by the assembly guide of figure 1. Please note that the PCB has 7 (seven) jumpers. Those jumpers are noted as blue- dashed-lines on figure 1. All jumpers are made from a copper wire.
The electronic schematic of the LED Christmas Bell
The Printed Circuit Board of the LED Christmas Bell