The post Christmas Light Contest 2023 first appeared on Delphijustin industries.

To use the standard ones just put a resistor in series defined by this equation

$$R=\frac{V_{in}-V_{f}}{0.001I_{f}}$$

R is the resistance in ohms, Vin is the supply voltage in volts, Vf is the voltage drop defined in the LED datasheet and If is the current defined in the LED datasheet. If you don’t know model of your LED or can’t find a datasheet use a 1k. It wont be the brightest but good enough.

You can also flash them by an Arduino, computer, 555 timer, etc…

Just remember that the output current sometimes might not be enough or the load could be too much, so you probably need a Transistor Switch circuit

You can get 20ft of wire for $2.60, 45x 12V LEDs for $20(you can get them cheaper without the built-in resistors) and a 12.5V power supply for $3.50 at allelectronics cost including shipping $34.10

To determine the total current draw we can use this equation, where Itotal is total current in milliamps, n is the number of LEDs and If is the LED current defined in the datasheet.

$$I_{total}=0.001I_{f}n$$

And for wattage:

$$P=0.001I_{f}nV_{in}$$

Where P is power in watts. If is LED current in milliamps, n is the number of LEDs and Vin is supply voltage.

The post DIY Holiday Lights first appeared on Delphijustin industries.