I had several LDRs lying around in my room so i decided to do a simple project with one of them. I made an LDR object counter. By the way for those who do not know, LDR stands for light-dependent resistor. If you have never used it before, take a few minutes to learn how to connect and use it with an arduino. Moreover, your knowledge of voltage dividers will come in handy when working with the LDR.
Teachers! Did you use this instructable in your classroom?
Add a Teacher Note to share how you incorporated it into your lesson.
Step 1: Controlling an LED
Step 2: Video
Step 3: LDR Counter
The LDR counter was a little bit complex than the led control setup. This is because i used a neopixel matrix to display the number of objects that had passed through.
The setup works on a simple principle. The LDR's resistance increases when there is no incident light shining on it. So, every time an object passes by and blocks light to the LDR we get a lower reading on the analog pin. Every time this happens the counter increases by one, just as shown in the video.
Step 4: Requirements
· 22k resistor
· Arduino uno
· WS2812b neopixel matrix
Step 5: Setup
The setup is as shown in the photo. You can learn how to connect the neopixel matrix to the arduino board here.