I have combined the Neopixel library with the Tinker app and am changing the color of the LEDs with input on the app! There’s some pretty strange behaviour though - I would appreciate having a fellow WS2812 enthusiast check this out.
This requires a bit of setup - on the board, pins A0, A1, A2 are jumpered up to A3, A4, A5 respectively. Then on the app, A0-A2 are set to analogWrite while A3-A5 are set to analogRead… this allows values to be adjusted on the analogWrite pins for input and use in the core program.
Code is as follows:
/**
******************************************************************************
* @file application.cpp
* @authors Satish Nair, Zachary Crockett and Mohit Bhoite
* @version V1.0.0
* @date 05-November-2013
* @brief Tinker application
******************************************************************************
Copyright (c) 2013 Spark Labs, Inc. All rights reserved.
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation, either
version 3 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this program; if not, see <http://www.gnu.org/licenses/>.
******************************************************************************
*/
/* Includes ------------------------------------------------------------------*/
#include "application.h"
/* Function prototypes -------------------------------------------------------*/
int tinkerDigitalRead(String pin);
int tinkerDigitalWrite(String command);
int tinkerAnalogRead(String pin);
int tinkerAnalogWrite(String command);
/*-------------------------------------------------------------------------
Spark Core library to control WS2812 based RGB
LED devices such as Adafruit NeoPixel strips.
Currently handles 800 KHz bitstream on Spark Core,
with LEDs wired for GRB color order.
Written by Phil Burgess / Paint Your Dragon for Adafruit Industries.
Modified to work with Spark Core by Technobly.
Contributions by PJRC and other members of the open source community.
Adafruit invests time and resources providing this open source code,
please support Adafruit and open-source hardware by purchasing products
from Adafruit!
--------------------------------------------------------------------*/
/* ======================= Adafruit_NeoPixel.h ======================= */
/*--------------------------------------------------------------------
This file is part of the Adafruit NeoPixel library.
NeoPixel is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as
published by the Free Software Foundation, either version 3 of
the License, or (at your option) any later version.
NeoPixel is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with NeoPixel. If not, see
<http://www.gnu.org/licenses/>.
--------------------------------------------------------------------*/
class Adafruit_NeoPixel {
public:
// Constructor: number of LEDs, pin number, LED type
Adafruit_NeoPixel(uint16_t n, uint8_t p=6);
~Adafruit_NeoPixel();
void
begin(void),
show(void),
setPin(uint8_t p),
setPixelColor(uint16_t n, uint8_t r, uint8_t g, uint8_t b),
setPixelColor(uint16_t n, uint32_t c),
setBrightness(uint8_t);
uint8_t
*getPixels() const;
uint16_t
numPixels(void) const;
static uint32_t
Color(uint8_t r, uint8_t g, uint8_t b);
uint32_t
getPixelColor(uint16_t n) const;
private:
const uint16_t
numLEDs, // Number of RGB LEDs in strip
numBytes; // Size of 'pixels' buffer below
uint8_t
pin, // Output pin number
brightness,
*pixels; // Holds LED color values (3 bytes each)
uint32_t
endTime; // Latch timing reference
};
/* ======================= Adafruit_NeoPixel.cpp ======================= */
/*-------------------------------------------------------------------------
This file is part of the Adafruit NeoPixel library.
NeoPixel is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as
published by the Free Software Foundation, either version 3 of
the License, or (at your option) any later version.
NeoPixel is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with NeoPixel. If not, see
<http://www.gnu.org/licenses/>.
-------------------------------------------------------------------------*/
Adafruit_NeoPixel::Adafruit_NeoPixel(uint16_t n, uint8_t p) : numLEDs(n), numBytes(n), pin(p), pixels(NULL)
{
if((pixels = (uint8_t *)malloc(numBytes))) {
memset(pixels, 0, numBytes);
}
}
Adafruit_NeoPixel::~Adafruit_NeoPixel() {
if(pixels) free(pixels);
pinMode(pin, INPUT);
}
void Adafruit_NeoPixel::begin(void) {
pinMode(pin, OUTPUT);
digitalWrite(pin, LOW);
}
void Adafruit_NeoPixel::show(void) {
if(!pixels) return;
// Data latch = 50+ microsecond pause in the output stream. Rather than
// put a delay at the end of the function, the ending time is noted and
// the function will simply hold off (if needed) on issuing the
// subsequent round of data until the latch time has elapsed. This
// allows the mainline code to start generating the next frame of data
// rather than stalling for the latch.
while((micros() - endTime) < 50L);
// endTime is a private member (rather than global var) so that multiple
// instances on different pins can be quickly issued in succession (each
// instance doesn't delay the next).
noInterrupts(); // Need 100% focus on instruction timing
volatile uint32_t
c, // 24-bit pixel color
mask; // 8-bit mask
volatile uint16_t i = numBytes; // Output loop counter
volatile uint8_t
j, // 8-bit inner loop counter
*ptr = pixels, // Pointer to next byte
g, // Current green byte value
r, // Current red byte value
b; // Current blue byte value
while(i) { // While bytes left...
mask = 0x1000000; // reset the mask, start 1 higher than
i--; // decrement bytes remaining
g = *ptr++; // Next green byte value
r = *ptr++; // Next red byte value
b = *ptr++; // Next blue byte value
c = ((uint32_t)g << 16) | ((uint32_t)r << 8) | b; // Pack the next 3 bytes to keep timing tight
for (j=0; j<24; j++) { // iterate through 24-bits of next pixel, MSB to LSB.
if (c & (mask >>= 1)) { // mask shifts first, then & with c
// 700ns HIGH (meas. 694ns)
PIN_MAP[pin].gpio_peripheral->BSRR = PIN_MAP[pin].gpio_pin; // HIGH
asm volatile(
"mov r0, r0" "\n\t" "nop" "\n\t" "nop" "\n\t" "nop" "\n\t" "nop" "\n\t"
"nop" "\n\t" "nop" "\n\t" "nop" "\n\t" "nop" "\n\t" "nop" "\n\t"
"nop" "\n\t" "nop" "\n\t" "nop" "\n\t" "nop" "\n\t" "nop" "\n\t"
"nop" "\n\t" "nop" "\n\t" "nop" "\n\t" "nop" "\n\t" "nop" "\n\t"
"nop" "\n\t" "nop" "\n\t" "nop" "\n\t" "nop" "\n\t" "nop" "\n\t"
"nop" "\n\t" "nop" "\n\t" "nop" "\n\t" "nop" "\n\t" "nop" "\n\t"
"nop" "\n\t" "nop" "\n\t" "nop" "\n\t" "nop" "\n\t" "nop" "\n\t"
"nop" "\n\t" "nop" "\n\t"
::: "r0", "cc", "memory");
// 600ns LOW (meas. 598ns)
PIN_MAP[pin].gpio_peripheral->BRR = PIN_MAP[pin].gpio_pin; // LOW
} else {
// 350ns HIGH (meas. 360ns)
PIN_MAP[pin].gpio_peripheral->BSRR = PIN_MAP[pin].gpio_pin; // HIGH
asm volatile(
"mov r0, r0" "\n\t" "nop" "\n\t" "nop" "\n\t" "nop" "\n\t" "nop" "\n\t"
"nop" "\n\t" "nop" "\n\t" "nop" "\n\t" "nop" "\n\t" "nop" "\n\t"
"nop" "\n\t" "nop" "\n\t"
::: "r0", "cc", "memory");
// 800ns LOW (meas. 792ns)
PIN_MAP[pin].gpio_peripheral->BRR = PIN_MAP[pin].gpio_pin; // LOW
asm volatile(
"mov r0, r0" "\n\t" "nop" "\n\t" "nop" "\n\t" "nop" "\n\t" "nop" "\n\t"
"nop" "\n\t" "nop" "\n\t" "nop" "\n\t" "nop" "\n\t" "nop" "\n\t"
"nop" "\n\t" "nop" "\n\t" "nop" "\n\t" "nop" "\n\t" "nop" "\n\t"
"nop" "\n\t" "nop" "\n\t" "nop" "\n\t" "nop" "\n\t"
::: "r0", "cc", "memory");
}
}
} // end while(i)
interrupts();
endTime = micros(); // Save EOD time for latch on next call
}
// Set the output pin number
void Adafruit_NeoPixel::setPin(uint8_t p) {
pinMode(pin, INPUT);
pin = p;
pinMode(p, OUTPUT);
digitalWrite(p, LOW);
}
// Set pixel color from separate R,G,B components:
void Adafruit_NeoPixel::setPixelColor(
uint16_t n, uint8_t r, uint8_t g, uint8_t b) {
if(n < numLEDs) {
if(brightness) { // See notes in setBrightness()
r = (r * brightness) >> 8;
g = (g * brightness) >> 8;
b = (b * brightness) >> 8;
}
uint8_t *p = &pixels[n * 3];
*p++ = g;
*p++ = r;
*p = b;
}
}
// Set pixel color from 'packed' 32-bit RGB color:
void Adafruit_NeoPixel::setPixelColor(uint16_t n, uint32_t c) {
if(n < numLEDs) {
uint8_t
r = (uint8_t)(c >> 16),
g = (uint8_t)(c >> 8),
b = (uint8_t)c;
if(brightness) { // See notes in setBrightness()
r = (r * brightness) >> 8;
g = (g * brightness) >> 8;
b = (b * brightness) >> 8;
}
uint8_t *p = &pixels[n * 3];
*p++ = g;
*p++ = r;
*p = b;
}
}
// Convert separate R,G,B into packed 32-bit RGB color.
// Packed format is always RGB, regardless of LED strand color order.
uint32_t Adafruit_NeoPixel::Color(uint8_t r, uint8_t g, uint8_t b) {
return ((uint32_t)r << 16) | ((uint32_t)g << 8) | b;
}
// Query color from previously-set pixel (returns packed 32-bit RGB value)
uint32_t Adafruit_NeoPixel::getPixelColor(uint16_t n) const {
if(n < numLEDs) {
uint16_t ofs = n * 3;
return (uint32_t)(pixels[ofs + 2]) |
((uint32_t)(pixels[ofs ]) << 8) |
((uint32_t)(pixels[ofs + 1]) << 16);
}
return 0; // Pixel # is out of bounds
}
uint8_t *Adafruit_NeoPixel::getPixels(void) const {
return pixels;
}
uint16_t Adafruit_NeoPixel::numPixels(void) const {
return numLEDs;
}
// Adjust output brightness; 0=darkest (off), 255=brightest. This does
// NOT immediately affect what's currently displayed on the LEDs. The
// next call to show() will refresh the LEDs at this level. However,
// this process is potentially "lossy," especially when increasing
// brightness. The tight timing in the WS2811/WS2812 code means there
// aren't enough free cycles to perform this scaling on the fly as data
// is issued. So we make a pass through the existing color data in RAM
// and scale it (subsequent graphics commands also work at this
// brightness level). If there's a significant step up in brightness,
// the limited number of steps (quantization) in the old data will be
// quite visible in the re-scaled version. For a non-destructive
// change, you'll need to re-render the full strip data. C'est la vie.
void Adafruit_NeoPixel::setBrightness(uint8_t b) {
// Stored brightness value is different than what's passed.
// This simplifies the actual scaling math later, allowing a fast
// 8x8-bit multiply and taking the MSB. 'brightness' is a uint8_t,
// adding 1 here may (intentionally) roll over...so 0 = max brightness
// (color values are interpreted literally; no scaling), 1 = min
// brightness (off), 255 = just below max brightness.
uint8_t newBrightness = b + 1;
if(newBrightness != brightness) { // Compare against prior value
// Brightness has changed -- re-scale existing data in RAM
uint8_t c,
*ptr = pixels,
oldBrightness = brightness - 1; // De-wrap old brightness value
uint16_t scale;
if(oldBrightness == 0) scale = 0; // Avoid /0
else if(b == 255) scale = 65535 / oldBrightness;
else scale = (((uint16_t)newBrightness << 8) - 1) / oldBrightness;
for(uint16_t i=0; i<numBytes; i++) {
c = *ptr;
*ptr++ = (c * scale) >> 8;
}
brightness = newBrightness;
}
}
/* ======================= SparkPixel.cpp ======================= */
// Parameter 1 = number of pixels in strip
// Parameter 2 = pin number (most are valid)
// Pixels are wired for GRB bitstream
// 800 KHz bitstream (e.g. High Density LED strip) - WS2812 (6-pin part)
#define PIN D0
Adafruit_NeoPixel strip = Adafruit_NeoPixel(20, PIN);
int cRed=0;
int cGrn=0;
int cBlu=0;
/* This function is called once at start up ----------------------------------*/
void setup()
{
//Setup the Tinker application here
//Register all the Tinker functions
Spark.function("digitalread", tinkerDigitalRead);
Spark.function("digitalwrite", tinkerDigitalWrite);
Spark.function("analogread", tinkerAnalogRead);
Spark.function("analogwrite", tinkerAnalogWrite);
strip.begin();
strip.show(); // Initialize all pixels to 'off'
pinMode(A5, INPUT);
pinMode(A4, INPUT);
pinMode(A3, INPUT);
pinMode(A2, OUTPUT);
pinMode(A1, OUTPUT);
pinMode(A0, OUTPUT);
}
/* This function loops forever --------------------------------------------*/
void loop(){
//rainbowCycle(20);
cRed = analogRead(A5);
cGrn = analogRead(A4);
cBlu = analogRead(A3);
colorWipe( strip.Color(cRed,cGrn,cBlu), 100);
delay(100);
}
/*******************************************************************************
* Function Name : tinkerDigitalRead
* Description : Reads the digital value of a given pin
* Input : Pin
* Output : None.
* Return : Value of the pin (0 or 1) in INT type
Returns a negative number on failure
*******************************************************************************/
int tinkerDigitalRead(String pin)
{
//convert ascii to integer
int pinNumber = pin.charAt(1) - '0';
//Sanity check to see if the pin numbers are within limits
if (pinNumber< 0 || pinNumber >7) return -1;
if(pin.startsWith("D"))
{
pinMode(pinNumber, INPUT_PULLDOWN);
return digitalRead(pinNumber);
}
else if (pin.startsWith("A"))
{
pinMode(pinNumber+10, INPUT_PULLDOWN);
return digitalRead(pinNumber+10);
}
return -2;
}
/*******************************************************************************
* Function Name : tinkerDigitalWrite
* Description : Sets the specified pin HIGH or LOW
* Input : Pin and value
* Output : None.
* Return : 1 on success and a negative number on failure
*******************************************************************************/
int tinkerDigitalWrite(String command)
{
bool value = 0;
//convert ascii to integer
int pinNumber = command.charAt(1) - '0';
//Sanity check to see if the pin numbers are within limits
if (pinNumber< 0 || pinNumber >7) return -1;
if(command.substring(3,7) == "HIGH") value = 1;
else if(command.substring(3,6) == "LOW") value = 0;
else return -2;
if(command.startsWith("D"))
{
pinMode(pinNumber, OUTPUT);
digitalWrite(pinNumber, value);
return 1;
}
else if(command.startsWith("A"))
{
pinMode(pinNumber+10, OUTPUT);
digitalWrite(pinNumber+10, value);
return 1;
}
else return -3;
}
/*******************************************************************************
* Function Name : tinkerAnalogRead
* Description : Reads the analog value of a pin
* Input : Pin
* Output : None.
* Return : Returns the analog value in INT type (0 to 4095)
Returns a negative number on failure
*******************************************************************************/
int tinkerAnalogRead(String pin)
{
//convert ascii to integer
int pinNumber = pin.charAt(1) - '0';
//Sanity check to see if the pin numbers are within limits
if (pinNumber< 0 || pinNumber >7) return -1;
if(pin.startsWith("D"))
{
pinMode(pinNumber, INPUT);
return analogRead(pinNumber);
}
else if (pin.startsWith("A"))
{
pinMode(pinNumber+10, INPUT);
return analogRead(pinNumber+10);
}
return -2;
}
/*******************************************************************************
* Function Name : tinkerAnalogWrite
* Description : Writes an analog value (PWM) to the specified pin
* Input : Pin and Value (0 to 255)
* Output : None.
* Return : 1 on success and a negative number on failure
*******************************************************************************/
int tinkerAnalogWrite(String command)
{
//convert ascii to integer
int pinNumber = command.charAt(1) - '0';
//Sanity check to see if the pin numbers are within limits
if (pinNumber< 0 || pinNumber >7) return -1;
String value = command.substring(3);
if(command.startsWith("D"))
{
pinMode(pinNumber, OUTPUT);
analogWrite(pinNumber, value.toInt());
return 1;
}
else if(command.startsWith("A"))
{
pinMode(pinNumber+10, OUTPUT);
analogWrite(pinNumber+10, value.toInt());
return 1;
}
else return -2;
}
/*******************************************************************************
* NEOPIXEL FUNCTIONS
*******************************************************************************/
// Fill the dots one after the other with a color
void colorWipe(uint32_t c, uint8_t wait) {
for(uint16_t i=0; i<strip.numPixels(); i++) {
strip.setPixelColor(i, c);
strip.show();
delay(wait);
}
}
void rainbow(uint8_t wait) {
uint16_t i, j;
for(j=0; j<256; j++) {
for(i=0; i<strip.numPixels(); i++) {
strip.setPixelColor(i, Wheel((i+j) & 255));
}
strip.show();
delay(wait);
}
}
// Slightly different, this makes the rainbow equally distributed throughout
void rainbowCycle(uint8_t wait) {
uint16_t i, j;
for(j=0; j<256; j++) { // 1 cycle of all colors on wheel
for(i=0; i< strip.numPixels(); i++) {
strip.setPixelColor(i, Wheel(((i * 256 / strip.numPixels()) + j) & 255));
}
strip.show();
delay(wait);
}
}
// Input a value 0 to 255 to get a color value.
// The colours are a transition r - g - b - back to r.
uint32_t Wheel(byte WheelPos) {
if(WheelPos < 85) {
return strip.Color(WheelPos * 3, 255 - WheelPos * 3, 0);
} else if(WheelPos < 170) {
WheelPos -= 85;
return strip.Color(255 - WheelPos * 3, 0, WheelPos * 3);
} else {
WheelPos -= 170;
return strip.Color(0, WheelPos * 3, 255 - WheelPos * 3);
}
}
The program seems to behave strangely however - the colorWipe() works fine enough with its 100ms delay, but the lights flicker at random times and the Tinker inputs don’t always respond nicely - in fact, I can’t even get a steady reading out of A5. I am running a set of 20 LEDs with this, Neopixel init settings can be found on lines 332 and 333 of this code.
I would love to hear the results if anyone else tries this out!
On a side note, is there a way to drop this huge code block into a vertical scroll container?
I recommended stuff like this before and it completely slipped my mind this time around. You are basically just intercepting the values for analogWrite() if they are for A0, A1 or A2, and redirecting the PWM values to your 0xFFFFFF RGB 24bit value. Simple, and glitch free.