Anti-Sunflower - Points to Your Darkness!




About: I just wanna connect stuff...

Since childhood, I always wanted to try my hands on electronics. Recently I bought the Arduino and started exploring it. In this process, I got to know more about Light Dependent Resistors (LDR).

Somehow, I stumble across this idea. Basically, it's an electric sunflower which does the opposite of actual sunflower. It points to the darkness!!!

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Step 1: Stuff You Need

  • 3 LDRs
  • 3 10k Ohm resistors
  • A servo motor
  • Arduino Board
  • Few Jumper wires
  • Soldering Kit
  • Perforated PCB
  • Small Pot along with some dry soil.

Step 2: The Circuit

The crux is each LDR is responsible for an angle, left for 180 degrees, middle one for 90 degrees and right one for 0 degrees. For example, if the middle LDR not receiving any light and other LDRs are getting some light then

Arduino will receive following input:

  • Left LDR => HIGH
  • Middle LDR => LOW
  • Right LDR => HIGH

Based on this input, Arduino can compute the angle (90 degrees in this case) and send this information to the servo motor.

Step 3: The Code

In layman terms, that's what the code does:

  • It takes input from 3 LDRs.
  • Using this input, it calculates the amount of light each LDR is getting.
  • Now, it computes the angle it should go. For example if the right & middle LDR both are not getting any light, then the angle calculated will be 45 degrees (Mid angle of 0 degree & 90 degree is 45 degrees).

Find the code here.

Step 4: Build the Circuit

Use Perforated PCB to solder resistor and LDRs. Use the Arduino breadboard for connecting PCB and servo motor. Upload the code and test.

Step 5: Plant the Anti-sunflower

I've used a small pot and made a hole in it to pass the wires. Put some soil, keep the servo motor, add some more soil. Then just connect the servo motor with Arduino and you're done!

Step 6: The Flower in Action

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    4 Discussions


    9 months ago

    What a great idea! That's really fun, and a great way to use LDRs.

    1 reply