episode 38: LEDstrip fun, rand, and voltage drops

CBA Podcast

Hi there! Thanks for tuning in (or reading this text and then deciding not to tune in at all). Another episode with a mixed bag of semi-interesting topics.

Thanks for the feedback - the inter-segment jingle will be a bit less loud from now on. Poor ears.

We start off by counting pass & fail on this year's new year's resolutions, followed by mentioning a small inline PCB for driving LED-strips and so on. The PCB was used for 2 light effects so far - links to videos of both are given below.

Ran into a "gotcha" when dealing with LED-effects: intelligent LEDs stuck in "full brightness" mode, causing the supply to shit itself and the system to become unresponsive. (Quickfix: small delay between boot and start-of-effect at power-on.)

For the LED-effects, I measured rand() execution times (avr-gcc, avr-libc, ATmega168 @ 8 MHz) and was pleasantly surprised by its speed and predictability. Will use again.

Finally, some fuzzy guesstimates / measurements about what kind of voltage drop to expect when running current through long cables.

Relevant links:

• video of wallclock with WS2812 strip at home
• ...and one of a coffee table at Hackalot (Eindhoven, NL)
• Maker Faire Eindhoven on 28 & 29 September. Applications run (for now) until 31 July.

Snapshot of my inline PCB: