The Hat was conceived when I decided to embed a microcontroller in a large leather top hat and use it as a platform to experiment with various LED lighting technologies. In order to get something up and running quickly enough I decided to create a basic configuration which scrolled messages across an LED “billboard” and did some pretty things with a length of RGB LED strip wrapped around the hat’s crown. Although the initial “Hello World” version of The Hat would operate as a stand-alone application, I wanted to include wireless capability to make it easy for it to communicate with a Smartphone or another smart object and have access to the Internet.
I’d originally intended to use Arduino boards but decided to go with Texas Instruments after I learned that several of their Launch Pad development platforms had integrated wireless networking capabilities, and a nice set of drivers and application code available in both their Energia open-source development tool and their Eclipse-based Code Composer Studio pro-grade development environment. In the end, I went with the CC3200 SimpleLink Wi-Fi LaunchPad which includes a fully integrated radio, baseband, and MAC which can support an 802.11 b/g/n Station or Access Point, and a bunch of nice features which made development much easier. The ‘3200’s ARM 4 core is a minor bit of overkill for The Hat’s current configuration and I probably could have gotten along quite nicely with one of the MSP430-based LaunchPads which are also available. But I’m glad the folks at TI convinced me to “option up” since the extra MIPS will be nice to have for some of the upgrades and applications I’m pondering. And for $29, it’s a real bargain. I also ordered TI’s LaunchPad-compatible LiPo Battery BoosterPack to serve as a power source for the rig. It turns out that its 1200mAh capacity has enough juice to run the system at full brightness for roughly an hour so I was very glad that the processor board can also draw its power from an external source via its USB interface.
We considered several LED-based alphanumeric displays for the scrolling billboard and eventually settled on Omilex’s 2”x2” LED Matrix sections. As you’ll see in a later installment, their large size presented some mechanical challenges when I tried to mount them on The Hat but the readability those big displays provide made it worth the extra effort. For the RGB hat band, we bought a meter of weatherproof RGB LED Strip from Adafruit Labs, one of my favorite Maker Tech suppliers. Although moving the open-source drivers from the original Arduino libraries/sketches over to the Energia dev environment was not as easy as we anticipated, the extra effort paid off “glowingly” as we learned to program the strip’s LPD8806 processor to use its on-board 7-bit PWM channels to create colors by mixing the RGB LEDs and create some rather flashy lighting sequences.
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