[ILAMtitan]

Originally Posted by feverittm

I have been noting that some teams are thinking of connecting 'smart' led strings to their launchpad that is on their driver's station.

I thought that the current requirements of the WSxxxx type of addressable LED strings was much too high to connect to the regulator output from the launchpad (is the serial input on the leds 3.3V compatible?) or even USB power connections.

What are people thinking of using to provide power to these devices? Are you considering a second power plug (like a wall wart) to supply the additional current?

Thanks

Floyd Moore

Floyd, you're sort of right about the current limitation. The 3.3V rail of the LaunchPad is limited to what the DC/DC converter is capable of putting out. However, the 5V rail is directly connected to the USB output, and able to source 500mA. The SmartLEDs, like the WS2811 and WS2812, actually work better with a 5V source, and still run fine with the 3.3V digital serial output of the MSP430. The 500mA limit is problematic however, and running the LEDs off it can cause the host port to crash and resets of the MCU. It "works". Using a wall wart or other DC power supply is just fine if you connect the ground to the LaunchPad, and will enable you to source more current.

However, the LaunchPad is only capiable of running the SmartLEDs or the USB HID application, not both since they are both so timing critical dependent (I'm working on it though). If you're interested in just running LEDs, I've already made an Energia (http://energia.nu/) library for the LaunchPad to run the SmartLED strips. It emulates the AdaFruit NeoPixel library, and any Arduino code you already have for it should be 90% compatible with the LaunchPad via Energia. You can pick it up off my GITHub if you want to try it: https://github.com/ILAMtitan/WS2811Driver I'll be the first to admit it needs a readme, but it works just like the Arduino ones out there. If you need any support getting it running, just let me know.

Originally Posted by billbo911

So, the current plan is to actually control an addressable string of LEDs with an Arduino. The Arduino will be interfaced to a couple of the Digital outputs on the LaunchPad to know what pattern to display. The Arduino and the LEDs will get their power from a LiPo battery through a UBEC. That way, if the LiPo is not there, or too low, the LEDs just won't work, but the rest of the DS will function normally.

Since I want to do the same thing, I've kinda cobbled together a solution that I think works pretty well. I used a second LaunchPad to run the LED co-processor, which works well since they stack perfectly.



The middle board in the shot is the GamePad HID device using Option 1 from the utility. The top LaunchPad runs some code I wrote in Energia to read indicator pins 1-4 from the GamePad as a parallel input, and trigger prewritten animations based on the input code. All of the pins are set to HighZ otherwise, so they don't interfere with any of the GamePad functions. I ran some basic tests using an interface we wrote for the HID device testing, and the idea seems to work so far: https://www.youtube.com/watch?v=aLWZ5FOrozE

I also picked up the Fuel Tank Boosterpack I mentioned earlier to supply additional power, and enable the LEDs when it's unplugged: http://www.ti.com/tool/boostxl-battpack

There are a few caveats that I'm still working out (ie, it's super buggy still and very proof of concept), but I can post more info if you guys are interested.