Output Devices

Week11 - Apr 15 Output devices

WS2812B Technology

For This week we had to create a board and managing any kind of output. I decided to focus on my project "interactive climbing holds" . to light up my holds I will need 1,2 or 3 RGB leds by hold depending of the size of it. If we talk about 50 holds, I will have to manage more than 100 Leds, so for managing them without huge cabling and limiting the number of pin, I decided to use a led strip with WS2812B which is an intelligent control LED light source that the control circuit and RGB chip are integrated in a package. It's a 4 Pin componant (GND VCC Din Dout). you can cascade them :data outputs from each chip when the previous data overflows the chip buffer. The Chip/LED position in the chain determine the LED Address.Before the technology (WS2801) use SPI which require a clock line) now they using NZR which don’t require a clock line but relay on more strict timings of the data.the Data Transmission rate is about 400Kbps with an operation frequecy about 800KHz. It uses 24bits data frame:
G7 G6 G5 G4 G3 G2 G1 G0 R7 R6 R5 R4 R3 R2 R1 R0 B7 B6 B5 B$ B3 B2 B1 B0
You can find more information by reading the datasheet : .
It could be interesting to create the framing code by myself but unfortunatly the Fablab doesn't have an oscilloscope so I will be impossible to tune and debug. And honestly I running out of time.
But as it exist many open source softare library for Arduino and Teensy I will use Adafruit_NeoPixel library or FastLED library.

WS2812B Breakout

I first create a breakout for only one Led but keeping in mind to developpe the BRD file to be able to cascade the easilly.
note: the ws2812b is part of the Adafruit library for Eagle.



Then As the board is cascadable I just use Photoshop to create a bigger one (5 LEDs)


ADD pict and code sample

New Breakout for ClimbingHolds .. Project

I create another Breakout to be include directly under the hold at casting time:

Milling PCB adventures

bootloader and Test program

As it's fully compatible with Arduino UNO Burning the bootloader was very simple:

-Put the shield.
-Connect FTDI for the power
-Connect the ISP.
-Start Arduino IDE. select Arduino Uno and the programer Then Burn the bootloder.
That's it!!!

To program it you just have to plug the FTDI cable and its port then program it as an Arduino UNO.
I decided to test My JMDuino as well as the 2 Breakouts at the same time. So i have to download FastLED library and install it under Arduino IDE.

      
#include "FastLED.h"

// How many leds in the strip 
#define NUM_LEDS 9    /*4 in the 1st breakout + 5 in the second*/

// For led chips like Neopixels, which have a data line, ground, and power, you just
// need to define DATA_PIN.  
#define DATA_PIN 6


// Define the array of leds
CRGB leds[NUM_LEDS];

void setup() { 
	FastLED.addLeds(leds, NUM_LEDS);
}

void loop() { 
	// First slide the led in one direction
	for(int i = 0; i < NUM_LEDS; i++) {
		// Set the i'th led to red 
		leds[i] = CRGB::Red;
		// Show the leds
		FastLED.show();
		// now that we've shown the leds, reset the i'th led to black
		leds[i] = CRGB::Black;
		// Wait a little bit before we loop around and do it again
		delay(300);
	}

	// Now go in the other direction.  
	for(int i = NUM_LEDS-1; i >= 0; i--) {
		// Set the i'th led to red 
		leds[i] = CRGB::Red;
		// Show the leds
		FastLED.show();
		// now that we've shown the leds, reset the i'th led to black
		leds[i] = CRGB::Black;
		// Wait a little bit before we loop around and do it again
		delay(300);
	}
}

Uploading the software using Arduino IDE:


Victory It's working fine:

you can find all the eagle files and png file and progam files on my github repository :