- Overview, concept and background
Creation and build
- BeagleBone Black, USB Audio interface and speakers
- Implementing the light sensors that were read by the BBB
- Designing and driving the LEDs with power mosfets controlled by the BBB
- Programming the BBBs with node.js and Bonescript
- Challenges we had (both technically and with the weather)
The animal’s foam body is equipped with the LED strip that will eventually light up the critter from the inside out. As you can see above, we simply made a back-lit light box in the shape of an animal. That strip inside the foam body is the white LED light strip.
- 5000k color temperature white
- 120 LEDs / m
- LED Size: SMD3528
- IP68 waterproof rating
In the picture to the right, notice the silicone outer sheath plus the inner silicone jelly. A few comments about this: Most generic LED strips from China do not implement this robust IP68 rating. Volt Vision’s LED strips are used mostly outdoors and often in the sun. Because of this, we use materials that are more expensive than normal strips. We use silicone instead of epoxy for both the outer sheath and the internal jelly. We have learned through years of experience that the normal epoxy material yellows and cracks over time. The silicone material that we special order costs more, but is more professional and lasts for years. The IP68 rating comes from this dual protection layer. Volt Vision has confidently used these materials in many underwater projects.
Most LED strips nowadays come in 5 meter reels, and you can cut them to any desired length with scissors. We will be talking about the soldering and LED driver electronics in Part 5 of this series.
High Impact Polystyrene
The front “skin” of the light box is hand-painted using acrylic paint onto High Impact Polystyrene (HIPS) 0.040″ thick (40mils). In choosing a material, there is always a trade-off. If the material is too thin, it will easily tear and puncture. If it is too thick, it won’t let enough light through. This 40mil thickness is the sweet spot because it is thick enough to stand up to abuse, and thin enough to allow a nice, uniform glow.
And now for the paint: We have found that acrylic paint works excellently to give good detail for the paint job while still allowing adequate light to come through from behind. Gary used a clear coat finish to protect the paint job from bumps, scrapes and weather.
And if you’re wondering just how large these animals are, check out this photo of our deer next to a person.
Regarding scale, Gary has learned through experience that when you get things outside and any distance away from people, they get lost quickly. And because it’s an art project, we didn’t want that “larger than life” quality to go away. This is why all of our animal creations are roughly 2 to 3 times the size of an actual animal.
Thanks for reading! Check back for our next installment where we cover the BeagleBone Black, USB Audio interface and speakers for this Sounds of the Night project.