Project Logs

Collapse

• CRI, CCT, lm, W, V, and other acronyms!

  Andy Shinn • 09/05/2020 at 22:06 • 0 comments

  The beginning of my idea to build a key light akin to the Elgato Key Light. I don't necessarily think it can be done better or cheaper. But it should be fun to try. In the end I will gain a useful tool in lighting for my otherwise dark office space where I use my camera most. Hopefully, the project turns out well enough that you will want to build your own!

  I've ordered 3 different CCT LED strips to test brightness. I've also ordered some MOSFETs to build a simple circuit that can be PWM driven by a ESP32. The LED strips are all 12V but different watts per feet and lumens per watt. I've still got a lot of unanswered questions such as:
  

  • Voltage? Is it worth going 24V for a small amount of LEDs?
  • is 30 LED per meter good enough or should I look at 60 or even 120?
  • Unsure of the target lumens per watt and lumens per foot?
  • What power supply? Maybe a Mean Well APV-35-12 or 24?
  • The ESP32 will be 5V (USB) or 3.3V. A step down regulator like Pololu D36V6x or D24V10Fx?
  • What CRI should I target? What does it even mean?

  I ordered a simple 3D printed frame and some "sign white" 1/8 inch acrylic panels from TAP Plastics to test different opacities. I only had 5V RGB LED strip available to test and although the opacity looks OK. The LEDs are not nearly bright enough (the below image brightness was blown up a bit to show more how it looks to the naked eye).

  Hopefully, the 12V strips will look better and give me a chance to test max brightness, heat, power requirements, and frame sizing. My prototype drawing is a simple frame that can be printed and sandwich a panel between parts to hold it in place.

  The frame will likely need to be much larger so I can safely fit at least one 1/4 inch threaded insert somewhere for mounting. Undecided where the power supply, ESP32, and wiring will go.

View project log