In my prior Blogs:
Smart Solar Lighting Project - Initial design ideas
Smart Solar Lighting Project - Detailed design
Smart Solar Lighting Project - Mechanical designs
Smart Solar Lighting Project - Update 10/2/2020
I discussed my initial design thoughts and detailed design for my smart lighting project. Today I am updating my progress with some experiments concerning the light diffusers. Early on in this project, I had decided that the raw LEDs where creating toe bright 'hot spots' on the art glass panels, leaving an aesthetically unpleasing effect. Not really having too much experience with diffusers, I started with a shotgun approach of ordering a wide variety of acrylic samples from an online company (TAP Plastics - an pretty awesome company that I was very familiar with from living in California, but unfortunately not present in Texas). I ended up selecting six different items, with different texture and rates of transmission, varying from clear to white (no desire to tint at this point). On initial tests, I found that texturing offered little in way of diffusion, so I whittled the selection down to three choices. Here is a look at the choices:
From left to right the samples are:
- Satinice White Acrylic - White - This material has a light matte surface (both sides) with light diffusing beads embedded in the acrylic, providing up to 59% transmission.
- Lighting White Acrylic - This material has a smooth surface, with coloring to provide a white glow, providing up to 69% transmission.
- Satinice White Acrylic - Clear - This material has a light matte surface (both sides) with light diffusing beads embedded in the acrylic, providing up to 89% transmission.
Now I was ready to mount the diffuser panels on to the smart LED boards, using the diffuser standoffs. Here is a picture of the assembly (last panel was not affixed to leave access to the header used to attach either the programmer or UART for remote commanding):
Initially I had thought that the Satinice Clear did not provide enough diffusion, so I began to focus on the Satinice White and Lighting White panels. Here are some pictures of the two panel types:
The top two images are the Satinice White and Lighting White, respectively, with the camera's auto exposure selected midway between the two panels. Both image appear to be equally bright, but overexposed. The bottom two images are the Satinice White and Lighting White, respectively, with the camera's auto exposure selected at the center of one of the diffusers. Here it is a little easier to see a diffusers effect on the lighting (although it is not necessarily an accurate test, as repeatable, manual exposure might be fairer).
The next test would be the real differentiator, outdoor lighting at night. For this test, I had selected Satinice White panels on one side, and a combination of the Satinice Clear and no panel on the other side. Here are the side by side images of this test:
On the left is the result of a pair of the Satinice White panels attached. I really like this image, as it shows coloration and texture of the art glass panels, while obscuring the LED hotspots and the inter-workings of the light fixture (PCB and battery). One right is the result of a single Satinice Clear panel (bottom) and bare LED (top). I am still not happy with the bare LED part as it has too much of a hotspot, while the Satinice Clear seemed to do a pretty good job on the diffusion. The degree to which the PCB and battery show in the image is somewhat distracting to the overall effect. I might try to use a pair of the Satinice Clear panels tonight to see if it obscures the PCB/battery. I also plan to place the light fixture into its clear acylic tube to see if it has any effect of the lighting.
I might also want to circle back and capture some illumination readings to better quantify light levels.
I had this step on hold for a while, as I have been looking to buy a bandsaw to cut the acrylic panels in a safe manner. While I was comfortable in cutting the acrylic in 1" strips, the cutting of the strips into panels (1" x 1.625") was still a little dicey (so I choose to hand cut those), I will need to build a sliding sled fixture to move the acrylic smoothly ans safely across the blade. Oh no, more work!
Thanks for reading.....
Top Comments