It is almost Christmas so I made this really easy project which is to use a sensor to light LED in order to light the Christmas tree up. This is really similar to what I made last time, which is the Big Dipper, it is almost the same. Ｉwanted to make something similar but a little different with some more complex skills than the first one. I am really bad at doing Arduino but I want to improve it by going step by step so I made this. What I did is to add a sensor and that's basically it. Your hand must be close enough from the lightbulbs to light them up, then they will light up all at the same time with different colors.

Supplies

Breadboard x1

resisters x5

USB cables x1

jumper wires x11

ultrasonic sensor hc-sr04 x1

Step 1: Step1. the Circuit

For the circuit, the most important part is the sensor. Checking the wires connected to the sensor will have to be done carefully in order not to connect them wrong. But other than that, everything else is just the LEDs settings.

Step 2: Step2. the Code

https://create.arduino.cc/editor/JudyChiu/f4f2ae48-c3ef-4f9e-b6c0-2a833ac9a229/preview

Step 3: Step3. Extending the Wires

For the Christmas tree lightbulbs, the LEDs must be long enough, so just take some breadboard wires and connect them with the LEDs.

Step 4: Step.4 Making the Tree

Take whatever board you have (here I'm using a cardboard box ) and cut it into a Christmas tree shape. Then, color it and poke 5 holes ( for 5 LEDs) to connect the lightbulbs with the tree together into a big piece of cardboard. Then dig out two circle holes that matched the sensor, which is about 1.5cm diameter. Lastly, put the sensor into the hole, and it's done!