Christmas LED Light String Display

This project demonstrates the construction of a simple LED light string display utilizing seven 24V LED light strings. The project was designed for Christmas 2009 to adorn a balcony with lights. The light strings are widely available, particularly in Sweden, during the Christmas season. The hardware design is straightforward, employing a 24V 2A switching power supply controlled by a ULN2004A to manage the LED operation. An LM2576 switching regulator is incorporated to supply 5V to the PIC18F2550 microcontroller, as the voltage conversion from 24V to 5V represents a significant step. The circuit board is a single-layer design featuring through-hole components, making it easy to assemble. Connections to the LEDs are established using pin and spade style speaker connectors, compatible with the light strings.

The LED light string display circuit operates on a 24V supply, which is typical for outdoor lighting applications. The use of the ULN2004A, a high-voltage, high-current Darlington transistor array, allows for effective control of the LED strings by enabling or disabling the power to them based on signals from the PIC18F2550 microcontroller. This microcontroller is programmed to manage the timing and sequencing of the LED strings, providing various lighting patterns or effects that enhance the visual display.

The LM2576 switching regulator is crucial for stepping down the voltage from 24V to 5V, ensuring that the microcontroller operates within its specified voltage range. This regulator is selected for its high efficiency, which is important for minimizing power loss and heat generation, especially in applications where the circuit may be powered for extended periods.

The single-layer circuit board design simplifies the assembly process, making it accessible for hobbyists and those with basic soldering skills. The use of through-hole components contributes to the board's robustness and ease of handling during assembly. The pin and spade style connectors provide a reliable means of connecting the LED strings, ensuring secure and stable connections that can withstand outdoor conditions.

Overall, this project exemplifies a practical approach to creating a decorative LED display, combining readily available components with straightforward design principles to achieve an effective lighting solution for festive occasions.This project shows how to build a simple LED light string display using seven 24V LED light strings. I built this project for Christmas 2009 in order to decorate my balcony with lights. The light strings used are very common and (at least in Sweden) can be purchased from many places during the Christmas period. The hardware design is very simple a nd uses a 24V 2A switching power supply which is controlled via a ULN2004A to turn the LEDs on an off. An LM2576 switching regulator is used to provide the PIC18F2550 with 5Vs (I used a switching regulator since 24V to 5V is quite a large step).

The circuit board is a single layer board with through-hole components and is very easy to make. The connections to the LEDs are made though `pin and spade` style speaker connections (since that was what the light strings came with). Here is a picture of the completed board: If you like this site and want to help support future projects, or you just want to show appreciation for a project you built, used or enjoyed, please consider leaving a PayPal donation.

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