Teensy 2.0 ++ or 3.0

Hello, I am devising a solar-powered LED project for illuminating signage at music festivals.

I asked earlier if I should use the 2.0 or 3.0 to run my LPD8806 strips. The consensus was 2.0 ++ was better for those strips.

Now I am seeing the WS2811 running on 3.0 and its exciting, GREAT WORK!

Its my understanding that these strips are diff. from the LPD8806 and have no clock pin.

If I did upgrade to this format (3.0 and WS2811) how easy will it be to do basic code manipulations for fading colors and using analog sensor inputs?

thanks

I think the basic code manipulating RGB values would be about the same, the differences between actually using 8906 vs 2811's would likely be the underlying interface functions/libraries, and addressing. And also, the primary difference between the actual usability of teensy2 vs teensy3 is the TTL levels. teensy 2 is 5v where teensy3 is 3.3v.. Which means you'd need to use level converters for the teensy3 to interface with the LED strips looking for a 5v TTL input.

Though one thing I have to question about your project that you might want to watch out for, is power requirements. You mentioned wanting it to be solar powered. However ws2811 LED's and strips are pretty power hungry. A string of 60 is going to draw around 3A running full brightness white. It's workable for small displays, but i'm not sure how practical large solar/battery powered displays involving hundreds or thousands of LED's would be. It would require quite a large amount of solar panel area/quite large battery packs to get any kind of real usable life out of.

thanks.

Seems I will stick with teensy 2.0 for now, because I want to maintain 5 V when possible. Im planning on using an ADAFRUIT solar charger, 6 W panel and 3.7V 6600 mAh battery. I am planning on running 18 -30 LEDs off of this and tweaking the code so that its NEVER all white. I dont know if it will work as far as solar gain, battery life, etc....but it needs to run ALL NIGHT LONG. any advice appreciated

Power consumption should be pretty similar, unless you leave all the LEDs off for long periods of time. The WS2811 draws about 0.9 mA when the LED is off. I do not know what the LPD8806 draws, but I'd guess it's less.

However, when the LED is on, it's about 15 to 18 mA per segment, or about 50 mA for full white, probably an average of 25 to 30 mA for most colors. If most of the LEDs are on most of the time, the current consumed by the LEDs is far more than that used for the controller chips.

Teensy 3.0 uses less current than Teensy++ 2.0, and at lower voltage (you could run it from the 3.7V battery to VIN, rather than on the output of whatever 3.7-to-5V step-up converter you have), so using Teensy 3.0 should save some power. It's not a huge savings compared to the 18-30 LEDs, which are obviously the lion's share of all the power usage.

Every WS2811 that's been tested so far is able to use the 3.3 volt signal from Teensy 3.0, if connected through a series resistor to control the ringing and cross-coupling. It's also pretty simple to use a 74HCT245 to convert from 3.3 to 5 volts. The OctoWS2811 page has a section about this signal quality stuff.

In terms of battery life, if you run 20 LEDs at an average 30 mA each, that's 600 mA needed at 5 volts. If you convert 3.7 to 5 volts with 85% efficiency, that's 954 mA from your battery to get 600 mA into the LEDs. If you add 50 mA for everything else, a 6600 mAH battery ought to last about 10 hours. Draining a battery below some threshold (not sure exactly what it is for your battery type) can really shorten its lifespan, so you might want to do some sort of battery monitoring or a timer to prevent deep discharge.