Introduction: Surrounding Brightness Remind Machine

About this machine:

If your surrounding is too dark which might harm your eyes, there will be sound to remind you.


  • Arduino or Arduino Uno
  • Breadboard
  • Five wires
  • Arduino Speaker (with wire)

Step 1: Build Up the Device

  • Connect the photoresistor as the picture show
    • the positive electrode (the longer end) to D Pin
    • the negative electrode (the shorter end) to the resistor
  • Connect a wire from the negative sign(-) to the GND, and another wire from the positive sign(+) to 5V.
  • Connect the speaker with the device
    • The black line connects to [GND]
    • The red line connects to [~11]

Step 2: Copy the Code

Elements you can change:

  • You can change the reference value of brightness
    • The smaller the number, the darker the brightness
  • You can change the key of sound the speaker play
    • If you think the sound is too sharp, you may change it into another key

The link below:

Step 3: Make a Box

  • Prepare a box or some cardboard
    • Based on the size of your device, cut the box into a suitable size (My box has length 17cm, width 13 cm, height 8 cm. But however it is too deep for this device, an ideal height is approximately 3 to 5 cm)
  • Start to dig holes
    • You will have to dig 3 holes
      • 1. A hole through which the wire can pass
      • 2. A hole that show up the photoresistor
      • 3. One to two holes to stable the speaker outside of the box (let the wire of the speaker went through the holes from the outside first, then connect them to [GND] and [11~])

The final product should look like what the video showed.