teensy 3.1 and NeoPixel not working

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briandw
 
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Re: teensy 3.1 and NeoPixel not working

Post by briandw »

Just for the record, I did get it all working with the level shifter. It worked horribly with the older loader but was great with 1.18-rc3. Then my Teensy stopped taking updates right before the party for that I was making this for :(

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happyinmotion
 
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Re: teensy 3.1 and NeoPixel not working

Post by happyinmotion »

Sorry to hear you've had this problem. Different versions of the NeoPixel strips are more or less sensitive to the Voltage levels (and the data timing).

I've just tested a bunch of level shifters (write-up at happyinmotion.com). The 74HCT245 seems to be the only one that does a solid job.

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michaelmeissner
 
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Re: teensy 3.1 and NeoPixel not working

Post by michaelmeissner »

I wish there were lipo like batteries that gave out 5v directly (on the order of the 500maH or 1200maH batteries). Sure there are cell phone charger batteries, but they tend to be bigger, and you can use step-up converters, but those often times have problems with excess heat generation which are problematical on a costume.

Either that, or it would be nice if there were a 3.7v analog to the WS2812 lights.

As I mentioned previously, the 24 led ring is the first neopixel product that I bought that needs 5v (I have individual neopixels, a neopixel strip, and 12/16 led rings), but I suspect any future purchases will probably also need boost circuits when I'm using my lipo batteries for costumes.

1chicagodave
 
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Re: teensy 3.1 and NeoPixel not working

Post by 1chicagodave »

MichaelMeissner wrote:I wish there were lipo like batteries that gave out 5v directly (on the order of the 500maH or 1200maH batteries). Sure there are cell phone charger batteries, but they tend to be bigger...
I (almost exclusively) use the Duracell USB batteries to run my projects...including NeoPixel projects. They're 1150mAh and only 1.5" x 3.5" x 0.5", compared to this 1200 mAh LiPo which is 1.35" x 2.55" x 0.23".

and you can use step-up converters, but those often times have problems with excess heat generation which are problematical on a costume.
Seems like a good solution for this might be a combination of Adafruit's MintyBoost and USB LiPo charger boards. I'd like to throw that in to the Adafruit suggestion box! :)

Someone else just had a recent post where that would've been a great solution too.

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michaelmeissner
 
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Re: teensy 3.1 and NeoPixel not working

Post by michaelmeissner »

Yep, and I have a Duracell battery like that. I may need to get more (my battery is 2-3 years old, and probably time to upgrade it). My main USB charger battery though is about the size of an Arduino shield, and is harder to disguise (but it is also 5000maH and has 2 power ports).

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briandw
 
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Re: teensy 3.1 and NeoPixel not working

Post by briandw »

The LiPo option looks attractive, does anyone have experience with a voltage regulator that will do the job of 3.7 -> 5v?

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michaelmeissner
 
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Re: teensy 3.1 and NeoPixel not working

Post by michaelmeissner »

I've ordered voltage regulators from Pololu.com, which is primarily focused on robots, but their voltage regulators have good reps on other boards, since they are switching regulators and not linear regulators. Note, I haven't yet used these regulators for anything but just testing, so I don't know if they will get too hot. http://www.pololu.com/category/84/regul ... r-supplies

There are 3 types of regulators you can buy:
  • Step-up regulators that take power at a lower voltage and convert it to a higher voltage (such as you would get going from a 3.7v lipo to 5v);
  • Step-down regulators that take power at a higher voltage and convert it to a lower voltage (such as you would get going from a 9v non-rechargeable battery to 5v);
  • Step-up/step-down regulators that will take power below, at, or above the target voltage, and convert it to a given voltage (note, a step-up/step-down regulator is not as efficient as a regulator where you know if the input voltage is less than or greater than you want, but it allows you to connect to multiple power sources, and also to deal with batteries that give out different voltages depending on the charge level).
Any regulator can potentially emit heat, so be sure to try out the regulators in a safe place first, and don't touch the regulator with your fingers.

In terms of neopixels, you need to figure out how much amps you will need as well as the voltage in order to size the regulator, and possibly the number of batteries. This comes down to how bright you will be lighting each LED and how many LEDS you will have on at the same time. That's why I said, it would be nice if Adafruit provided a more turnkey solution for people that want blinky lights, but aren't to the stage of making their own power supply.

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briandw
 
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Re: teensy 3.1 and NeoPixel not working

Post by briandw »

Thanks for the link Michael. The Lipos from Adafruit worked just great as it with the Neopixels. I got a new Teensy since the previous one stopped taking updates. It's only a week late for the party the finally result was pretty good. Thanks for the help to everyone here.

https://vimeo.com/86803967

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charly86
 
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Re: teensy 3.1 and NeoPixel not working

Post by charly86 »

Hi Guys,

Very interesting post, I'm currently using a ATMEGA328 to drive 6 start of LPD8806 led strip powered by huge Lipo (6600mAH). As my board is using RFM12B module and SD Card, all logic and core are regulated to 3V3 and the power of strip directly powered from Lipo. this mean that the STRIP is powered from 4.2V to 3.3V (depending on lipo charge) and clock/data signals are issued from Atmel at 3.3V
Everything is working fine (description and schematics of the board are here http://hallard.me/arduiled/

I saw Paul article after conception, but will improove this on new version that will use a Teensy 3.1 (Arduino with 500+ LED, + RF module, + SD Card + Oled display is hard to fit, but works with RAM shared buffer between devices !!!). I want to also use WS2812B, got some strip at home (WS2812 and WS2812B) and I will test from which power it can work, because if it does not work at 3.3V but works at 3.8V (lipo) it could be fine, I really need to test this point.
If it is 5V only, it's not a good news until we can find 5V Lipo battery (because step up converter will be too short to drive 500+ LED, consumption will be too high).

I will post my result soon, I have no board left, they currently are ready to a show, I will get them back after the show and do some tests

Stay tuned ;-)

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charly86
 
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Re: teensy 3.1 and NeoPixel not working

Post by charly86 »

Hi Guys,

Just tested the Adafruit NeoPixel library with custom Arduino board powered by Lipo, direct from the lipo I have a 3.3V regulator to power the Arduino Side (because I drive 3.3V devices) and then, the strip is powered directly from the lipo power (so say from 4.2V to 3.0V depending on battery charge). With WS2812B it works fine !!!!
Even if it is not the 5V needed, it's working and looks good. So may be we need a 74HC245 only if there is a too much difference between voltage control and strip power voltage.
If strip is powered with 5V and MCU with 3.3V this provide 1.7V difference. But with lipo 4.2V difference is only 0.9V (4.2V-3.3V).

Just for information, I'm happy because I do not need to change anything to migrate my LBP8806 to WS2812B on my project and boards, fine ;-)

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michaelmeissner
 
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Re: teensy 3.1 and NeoPixel not working

Post by michaelmeissner »

Just a note, PJRC started selling their OctWS2811 teensy 3.x carrier (http://www.pjrc.com/store/octo28_adaptor.html) to simplify hookups for the bigger WS2811 setups, complete with the 74HC245, etc. and using a pair of Cat6 cables to distribute the 8 strands of lights. I thought I remembered somewhere that Paul mentioned Adafruit might be selling this in the future, so be sure to check back on new products here.

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tcl987
 
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Re: teensy 3.1 and NeoPixel not working

Post by tcl987 »

Even if it is not the 5V needed, it's working and looks good. So may be we need a 74HC245 only if there is a too much difference between voltage control and strip power voltage.
The datasheet for the WS2812 leds lists a supply voltage range of 3.5V-5.3V and that an input high should be greater than 0.7*VDD so you should be fine with only 3.3V data signals for a supply voltage of 3.5V-4.2V.

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michaelmeissner
 
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Re: teensy 3.1 and NeoPixel not working

Post by michaelmeissner »

Be sure to check the datasheet for the WS2812B, which is replacing the WS2812: http://www.mikrocontroller.net/attachme ... minary.pdf. While it says the power supply voltage should be in the range 3.5-5.3v, the data voltage must be in the 4.5-5.5v range. It may be that some WS2812B's will tolerate 3.3v, it is not guaranteed. So, it means Gemma and Flora wearable projects may not work over time as you get newer neopixels.

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jonnymac
 
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Re: teensy 3.1 and NeoPixel not working

Post by jonnymac »

The TC4427 makes a nice little level-shifter for 3.3V devices -- I use it with the Propeller for controlling WS2812/B strings, especially when the connection between the Propeller and the WS2812/B is more than a couple inches.

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