PicoC Project: RGB LEDs

Hardware

We need ATTiny45 or ATTiny85 and WS2812 LED scripts
Save this code to your device:

/**
 *****************************************************************************
 * @file       NeoPixel_Transceiver.ino
 * @author     ernieift, main code, Copyright (C) 2014
 +             cGiesen, selftest
 * @brief      protocol converter to use rgb led stripes at async serial ports
 * @see        The GNU Public License (GPL) Version 3
 *
 *****************************************************************************/
/*
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU 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 General Public License
 * for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

/* pinout used on ATtiny85
 * pin 1 -
 * pin 2 RX comes from host
 * pin 3 TX (not used at yet)
 * pin 4 GND
 * pin 5 DOUT goes to LED stripe
 * pin 6 -
 * pin 7 -
 * pin 8 VCC
 */

#include <SoftwareSerial.h>
#include <Adafruit_NeoPixel.h>

/* global definition */
#define TIMEMAX 3

/* Serial definition */
#define RXPIN 3
#define TXPIN 4
#define BAUDRATE 9600
SoftwareSerial softSerial(RXPIN, TXPIN);

/* LED definition */
// Parameter 1 = number of pixels in strip
// Parameter 2 = Arduino pin number (most are valid)
// Parameter 3 = pixel type flags, add together as needed:
//   NEO_KHZ800  800 KHz bitstream (most NeoPixel products w/WS2812 LEDs)
//   NEO_KHZ400  400 KHz (classic 'v1' (not v2) FLORA pixels, WS2811 drivers)
//   NEO_GRB     Pixels are wired for GRB bitstream (most NeoPixel products)
//   NEO_RGB     Pixels are wired for RGB bitstream (v1 FLORA pixels, not v2)
#define LEDPIN 0
#define LEDMAX 100
Adafruit_NeoPixel strip = Adafruit_NeoPixel(LEDMAX, LEDPIN, NEO_GRB + NEO_KHZ800);

void setup() {
  strip.begin();
  strip.show(); // Initialize all pixels to 'off'
  softSerial.begin(BAUDRATE);
}

void loop() {
  enum machinestates {
    STATE_IDLE=0,
    STATE_RECEIVE_R=1,
    STATE_RECEIVE_G=2,
    STATE_RECEIVE_B=3,
    STATE_SEND=4
  };

  uint8_t oldState, newState;
  uint8_t timeout;
  uint16_t n;
  uint8_t r,g,b;
  
  /* Selfttst */
  r=0;
  g=128;
  b=250;
  
  while (softSerial.available() == 0) {
    r++;
    g++;
    b++;
    strip.setPixelColor(0, r, g, b);
    if (r > 254) r=0;
    if (g > 254) g=0;
    if (b > 254) b=0;
    strip.show();
    delay(10);
  }

/* Main loop */

  oldState = STATE_IDLE;
  newState = STATE_IDLE;
  timeout = 0;

  while (1) {
    switch (oldState) {
      case STATE_IDLE:
        if (softSerial.available()) {
          n = 0;
          newState = STATE_RECEIVE_R;
        }
        break;
      case STATE_RECEIVE_R:
        if (softSerial.available()) {
          r = softSerial.read();
          newState = STATE_RECEIVE_G;
        }
        break;
      case STATE_RECEIVE_G:
        if (softSerial.available()) {
          g = softSerial.read();
          newState = STATE_RECEIVE_B;
        }
        break;
      case STATE_RECEIVE_B:
        if (softSerial.available()) {
          b = softSerial.read();
          strip.setPixelColor(n, r, g, b);
          newState = (++n < LEDMAX) ? STATE_RECEIVE_R : STATE_SEND;
        }
        break;
      case STATE_SEND:
        strip.show();
        delay(1);
        newState = STATE_IDLE;
        break;
      default:
        newState = STATE_IDLE;
    }

    if ((newState != oldState) || (oldState == STATE_IDLE)) {
      timeout = 0;
    }
    else if (timeout >= TIMEMAX) {
      newState = STATE_SEND;
    }
    else {
      delay(1);
      timeout++;
    }

    oldState = newState;
  }
}

Soldering

Selftest
The first LED of you strip change the color until the first serial signal is received.

PicoC
You can start with this example.
I use 3 LEDs

When you start this script, the outer LEDs become red and the middle one red, until you’r disarmed.
When the copter is armed, the outer LEDs become green to.
This is only an startup example to test the hardware. I like to enhance this code to show GPS and Battery status.
And perhaps warning for FAILSAFE, LOWBAT, LOST_GPS e.t.c.

#include "system.h"

#define nLED 3
unsigned char bufLED[nLED*3];

void setLED(unsigned short n, unsigned char r, unsigned char g, unsigned char b) {
	if (n < nLED) {
		unsigned short offset = 3*n;
		bufLED[offset++] = r;
		bufLED[offset++] = g;
		bufLED[offset++] = b;
	}
}

void sendLED() {
	ChangeBaud(9600);
	SendBuffer(bufLED, sizeof(bufLED));
}	

/* end of RGB-LED library */

short LEDupdate=1;
short TMParmed=2;
short r=0,g=0,b=0;

TestValSet(1);
while(TestValGet() > 0)
{
	if (armed() && (TMParmed != 1))
	{	
		setLED(0,170,0,0);
		setLED(2,170,0,0);
		TMParmed = 1;
		LEDupdate=1;
 	} 
	else if (!armed() && (TMParmed != 0))
	{
		setLED(0,0,170,0);
		setLED(2,0,170,0);
		TMParmed = 0;
		LEDupdate=1;
	}

	setLED(1,170,0,0);
	if (LEDupdate == 1) {
		sendLED();
		LEDupdate = 0;
	}

	delay(500);
}
TestValSet(2);