Many novice photographers don't know how bright the lights are, or how much brightness they want to adjust when they first shoot. And this device is used to solve the troubles of novice photographers. I will use a photoresistor to confirm that the light in the shed is the best light. When the light is insufficient, it will light red, and when the light is enough, it will light green, and when the light is too bright, it will light yellow.
Arduino Board (Preferably Leonard or Uno) x1
Resistor 82 ohm x4
A box (you can also DIY a box too)
Step 1: Making the Circuit
Follow the given picture and you will be able to have the basic circuit for the device
Step 2: Making the Box/Drilling a Hole for It
If you are making your own box like me be sure to be careful when you are using a drill. Also, the hole doesn't need to be too big, so being able to let the pin come out from the other side will be good enough.
Step 3: Putting Everything Together
Next, follow picture 1, then stick the box together.
Tip: If the wire is easy to drop you may use tape/glue/solder to make it firmer, so it won't drop easily.
Tip 2: You may also make the top board able to open, so if the wire drops you may put it back.
Step 4: Code
Step 5: (Last) Your Done!
Here's the video of the device working