Review Led Options

 
#31

The Arduino code I hacked together ages and updated not too long ago can address from 1 to 24 neopixel as is. You can use a serial interface to set individual pixels to RGB color values or use the preprogrammed patterns and color fades. The color fades may be useful to you. They do make a new addressable LED that is generally known as dot star which the ez-b should be able to control directly, it has both a clock line and a data line so it is not timing dependent. I have only seen them in strings or boards so far. Programming for dotstars would take a bit of work but should not require an Arduino.

#32

I actually have a meter of Dot stars, but have no idea how to write code for them.

I may have a few questions for you as I progress. You mind if I bug you ?

#33

Don't know how much I can help. I don't have any myself. I have just be reading up on them a little. As they are interesting for Persistence of Vision projects and I have always wanted to make a persistence of vision device.

Links for reference on the Dotstars are:

https://cdn-shop.adafruit.com/product-files/2343/APA102C.pdf

I ran across a blog that addressed programing them a little at:

https://cpldcpu.com/2014/11/30/understanding-the-apa102-superled/

There is an arduino library to use them available thru adafruit. Or an LED driver library called FASTLED. Just post here and I will reply with whatever help I can give.

#34

....sorry i wasn't clear...i meant if i choose the neopixel route and use the code your wrote.

#35

Either myself or CochranRobotics can help with the neopixels. I was thinking that my code for the neopixel ring could be modified to function with the dotstar light strips using the same commands as it uses for neopixels.

#36

That would be cool. I looked into the links you sent and would be nice to do away with an “inbetween” board and be able to go straight to the EZB.

#37

The issue with using the EZ-B to drive a dostar string directly might be speed. I don’t know how many dotstar leds you could drive with a reasonable amount of speed. You would need to use two pins to control the dotstar leds. One pin would be the clock pin. The other pin is the data pin. To start a transaction with the dotstars you need to set the data pin low then pulse the clock pin from low to high and back to low 32 times. This is the start frame. The next comes what the documentation calls an LED frames. One frame for each led in the string. Once all of the dotstar led have each received a frame an ending frame needs to be sent. This means setting the data pin to high and pulsing the clock pin from low to high and back to low 32 times. Have to look up the data pattern for the LED frames but each LED frame is 32 bits. So send 32 bits for each LED frame. From what I gather there are some variation in dotstar LEDs. They do not all you the same color order. The first 8 bits of the LED frames address a global register that affects all three colors. The next 24 bits may vary but it is 8 bits for each color. The color order varies. For example some are RED, GREEN, BLUE; Some are BLUE, GREEN, RED, etc. So it will take some tinkering to figure out what the color pattern is. Lots of bit bashing as it called to make it work. But definitely doable. For each of the 32 bits in an LED frame the clock pin must be pulsed from high to low then back to high.

I wish I knew how to make plugins. Seems to me that a plug-in could do most of the work.

#38

Yes I agree a plug in would be great.

In the mean time I’m back to the neopixels. I’m going to load up the code from tutorials page onto a Adafruit Gemma (ardurino mini) I have and test to see if I can do what I want ( color fade, almost like a 2 color rainbow) with sliders.

#39

The Adafruit Gemma is not the same as arduino mini. There is actual a product called the arduino mini.

The Adafruit Gemma does not have a standard serial port available. The fix is to use the arduino "SoftwareSerial Library". Be sure to assign the Serial Port pin in the code with the SoftwareSerial Library on the original Gemma.

The Adafruit Gemma M0 does have standard serial ports available. Not sure how the serial interface works on the Gemma M0. I don't have one. There should be documentation on it somewhere on the Adafruit site.

I have not tinkered with the arduino mini serial port setup so I can't give you any hints on it. should be documentation on using serial ports with it as well.

Just be sure you modify the pins correctly in the code for what you need.

#40

Glad i didnt get to it today. I had not looked closer at the Gemma. I just ordered the Pro Trinket. Its about as big as i can go in the space I have. Seems full featured, has the same ATmega as the uno. But you are limited to about 28k in code size.


https://www.adafruit.com/product/2000