Ok... I must be doing something wrong.

Archive FastLED Archive
,
1

Ok… I must be doing something wrong. I just wired up my Teensy 3.6 and still can’t get any FastLED code to work.

The Adafruit Dotstar library works great which means my wring is correct.

Here is the Gist of what does work.

and here is Gist of something that won’t.

If I upload the Dotstar Lbrary code it works great, the FastLED code just doesn’t do anything.

I have tried using a Teesny and an Adafruit Feather, both give me the same issue.

I had the same issue a few months ago on my Uno and thought it was an issue with that.

Any thoughts?

Thanks

Phil

2

Ok… the plot thickens…

I tried some WS2811 pixels in case it was something to do with APA102. I ran the blink sketch and it worked. I then tried my APA102 and the blink worked on those too. But then it stopped working and I couldn’t get it to work again. The Adafruit sketch ran perfectly every time.

I stripped down my wires and circuits so there was no external power and minimal breadboard jumpers. As I was only trying to blink one LED, power wasn’t an issue.

Once I did that, I got a different result. The Adafruit library still works great but when I try the simple blink (link below)

It seems like it was illuminating every 4th pixel every second.

You can see the result in this video.

Now… If I change the delay from 500ms to 10ms the lights illuminate much quicker.

But what should be happening is just LED #5 blinking.

It is so odd that using the same circuit and microcontroller will work with one library but not another.

I cannot getting working again with FastLED even though I did have it blinking for a few moments…

3

Try different values of DATA_RATE_MHZ see https://github.com/FastLED/FastLED/wiki/Basic-usage for the syntax

4
5

@Phil_Spitler - Are you using the latest version of FastLED? Are you using a level shifter? Can you post a picture of your setup?

I have been running the current version FastLED on a Teensy 3.6 using the Arduino IDE 1.8.3 along with the Teensyduino 1.37 on Windows 7 using a 74AHCT125 level shifter without any problems since August. Try this running this sketch on your WS2811 pixels:

Be sure to change the led type to WS2811 and the number of leds to what you are using. Also change line 19 to what millamp max you want. I have run this sketch on up to 100 WS2811 pixels on a Teensy 3.6 using a 74AHCT125 level shifter without any problems.

6

@Ken_White I am not using a level shifter at all could that be the issue?

7

@Phil_Spitler - Yes, you do need it. I have always used a level shifter with my Teensy 3.1, 3.2 and 3.6 since it was posted here many times that you need it.

I just ran my code listed above on my Teensy 3.6 with the 74AHCT125 level shifter and it worked fine on my WS2811 pixels. When I connected the Teensy 3.6 directly to the WS2811 pixels without a level shifter , not one turned on. Definite proof that you do need the level shifter between the Teensy 3.6 and the pixels you are using if your pixels are expecting a 5 volt data input signal.

8

So weird that when I use that Adfruit library with the same hardware it works great without a level shifter.

9

Would something like this work?

10

Like @Will_Tatam said, try lowering the DATA_RATE_MHZ, before trying anything else. The Adafruit DotStar library likely doesn’t try to run the LEDs as fast as FastLED.

If that doesn’t work, everyone here recommends the 74HCT245 level shifter. Others might work, but that is the only one that has always worked. You need a very fast level shifter, and most don’t cut it. I have been able to use the slightly smaller 4 channel 74HCT125.

11

@Jason_Coon what is a good value to lower the data rate too? I’ll try that first.

Thanks

12

@Phil_Spitler try 1, see if it works. If so, try 2, etc, until it stops working.

13

Here’s the wiring setup for the 74HCT245 if you go that route.

14

I finally got to trying to lower the rate and it seems to have worked. Anything above 4 has issues but it seems to be working great at 4 (so far). Thanks for all the help… much appreciated