Part 2: Phones, Cans and Strings of Light
For an introduction to the project, start with Part 1.
Introducing... SHINY GOLD PHONES!!!!
We’ve decided to replace the tin cans from previous versions with shiny gold phones. We made this choice for a couple of reasons. First, the microphone and speaker we put in the tin cans originally were causing feedback problems. It is technically possible to work around this issue (your laptop does, for example), but it was adding complexity and frustrations. Second, and more importantly, the phones are very shiny :) Shiny is above all the most important thing.
Name of our new shiny phones a fantastic coincidence
We drove to the states to get these phones and have lunch. And look, we got em! Heck yeah!
Inside the Phones
Balanced audio is a new and necessary addition. Sandwiching audio lines between two strips of addressable LEDs causes great deal of noise in the lines. All that audio noise, especially combined with feedback from the tin cans we were using before, was really cramping the Mosh's style.
Grant designed custom boards that will fit inside the phones and send / receive audio, as well as boards to receive and send balanced audio from the main controller. Ethernet is great for this because flat shielded ethernet (like this) sandwiches well between two LED strips, and allows us to send balanced audio down twisted wire pairs.
Strings of Light
For the strings of light, we used WS2812b addressable strip, density of 96 leds per meter. If we were to do it over, I may have used less dense strip for this project. The pros of using high density strip is that it casts a lot of light, and gives you lots of resolution for a smooth effect. There are also cons though. Using strip this dense means more money, more power, and more processing. Keep density in mind when working on these types of projects - more isn’t always necessarily better with large scale pieces.
Running two LED strips back-to-back is important for aesthetics - it just looks way better. Using that flat ethernet cable I mentioned before is ideal to sandwich between two LED strips. From there, we held the LED strips and ethernet together with clear heat shrink and white braided sleeve for extra hold and diffusion.
OK, Actually more like tubes of light...
Moshi Moshi is primarily being deployed outside in west coast BC weather. It can (and probably will) rain at any time. We need to put our light strings in protective tubes.
One gotcha with this PVC tube is that it tends to want to stay bent, and aesthetically this doesn't look as good. Thanks to our friend the internet we discovered you can get PVC tubing straight by running boiling hot water through the tube and then reshaping while it’s hot. So, we boiled some water and I stood on the counter and poured boiling hot water through the tubes while grant held the bottom in a big pot. Twice. This worked really well and the tubes are much closer to straight now!
There we go, much better!
Attaching the tubes to the phones was a bit of a process as well. Luckily, the plastic these phones are made of doesn't crack easily, so we were able to drill a large hole and the base to fit the tube through. To add extra mechanical strength so the tubes won't pull out, we pierced the tube with a nail and added some epoxy. To ensure that the ethernet and led strips won't slip around in the tube, I stapled the the ethernet cable to the tube to grip it in place.
Another design consideration worth noting here is that it's important for us to be able to take these components apart fairly easily for repairs. The addressable LED strip is really intended for stationary applications. Since our phones move around as they are used, small connection problems in the LED strips are common. Any one bad connection will interrupt the rest of the LEDs. So as tempting as it is to slather hot glue everywhere, it was important to resist that urge.
Putting it all together
Of course testing the I/O (both audio and LEDs) was part of this process as well. Minus a few connection issues, we got them all working. Hooray!
Next time on How to Make a Conversation Cloud: Part 3 -Rhomdiddies! We'll talk about the structural construction of the cloud.
Show me what you got, Niel!