Arduino UNO驱动MPR121接近电容式触摸传感器控制WS2812彩灯

简介

MPR121芯片功能强大可用作触摸,电容检测,驱动LED等等.在低速扫描下可以将功耗降低到8μA,可以处理多达12个独立的触摸板。支持I2C,几乎可以用任何微控制器连接。可以使用ADDR引脚选择4个地址中的一个,一个I2C2线总线上共有48 个电容触摸板。使用该芯片比使用模拟输入进行电容式感应要容易得多,并且可以配置灵敏度。

参数特性

工作电压:2.5V-3.6VDC
采样频率:采样间隔时间为16ms时,电源电流为29μA,停止模式电流3μA
输出接口:12个电容传感输入
输入接口:8个输入为LED驱动器和GPIO多功能
完整的触摸检测:每个传感输入的自动配置自动校准
触摸/释放阈值和去抖动以进行触摸检测
I2C接口,带中断输出
工作温度范围:-40℃至+85℃
尺寸:30.5*20.6mm

引脚定义

名称	描述
IRQ	开路集电极中断输出引脚，低电平激活
SCL	I 2C时钟
SDA	I2C数据
ADDR	I 2C地址选择输入引脚。将ADDR引脚连接到VSS、VDD、SDA或SCL线，得到I2C地址分别为0x5A、0x5B、0x5C和0x5D
VREG	内部调节器节点
VSS	地
REXT	外部电阻器-将一个75 kΩ1%的电阻器连接到VSS，以设置内部参考电流
ELE0 - 11	电极0 - 11
VDD	电源输入

典型应用实例及电极图案

硬件准备

Arduino UNO板、MPR121电容触摸模块、WS2812模块。

引脚接线

MPR121 / WS2812	Arduino UNO
MPR121-SCL	A5
MPR121-SDA	A4
WS2812-IO	IO8
MPR121-3.3V	3.3V
WS2812-5V	5V
GND	GND

示例代码

#include <Wire.h>
#include "Adafruit_MPR121.h"
#include "FastLED.h"
#ifndef _BV
#define _BV(bit) (1 << (bit))
#endif

#define NUM_LEDS 9 
#define LED_DT 8 
#define LED_TYPE WS2812 
#define COLOR_ORDER RGB

CRGB leds[NUM_LEDS]; 
CHSV myHSVcolor(45, 255, 200);

// You can have up to 4 on one i2c bus but one is enough for testing!
Adafruit_MPR121 cap = Adafruit_MPR121();

// Keeps track of the last pins touched
// so we know when buttons are 'released'
uint8_t parseNum = 0;
uint8_t paletteNum = 0;
uint8_t startIndex = 0;
uint8_t chromatism = 50;
uint16_t lasttouched = 0;
uint16_t currtouched = 0;

void setup() {
  LEDS.addLeds<LED_TYPE, LED_DT, COLOR_ORDER>(leds, NUM_LEDS);
  FastLED.setBrightness(128);

  Serial.begin(9600);

  while (!Serial) { // needed to keep leonardo/micro from starting too fast!
    delay(10);
  }

  Serial.println("Adafruit MPR121 Capacitive Touch sensor test");

  // Default address is 0x5A, if tied to 3.3V its 0x5B
  // If tied to SDA its 0x5C and if SCL then 0x5D
  if (!cap.begin(0x5A)) {
    Serial.println("MPR121 not found, check wiring?");
    while (1);
  }
  Serial.println("MPR121 found!");
}

void loop() {
  // Get the currently touched pads
  currtouched = cap.touched();

  for (uint8_t i = 0; i < 12; i++) {
    // it if *is* touched and *wasnt* touched before, alert!
    if ((currtouched & _BV(i)) && !(lasttouched & _BV(i)) ) {
      switch (i) {
        case 0:
          stateLed_ON(parseNum++);
          if (parseNum > 10) {
            parseNum = 0;
          }
          break;
        case 1: stateLed_OFF(); break;
        case 2:
          dynamicLED(paletteNum, startIndex);
          paletteNum++;
          if (paletteNum > 1) {
            paletteNum = 0;
          }
          break;
      }
    }
  }

  // reset our state
  lasttouched = currtouched;

  // comment out this line for detailed data from the sensor!
  return;

  // debugging info, what
  Serial.print("\t\t\t\t\t\t\t\t\t\t\t\t\t 0x"); Serial.println(cap.touched(), HEX);
  Serial.print("Filt: ");
  for (uint8_t i = 0; i < 12; i++) {
    Serial.print(cap.filteredData(i)); Serial.print("\t");
  }
  Serial.println();
  Serial.print("Base: ");
  for (uint8_t i = 0; i < 12; i++) {
    Serial.print(cap.baselineData(i)); Serial.print("\t");
  }
  Serial.println();

  // put a delay so it isn't overwhelming
  delay(100);
}

void stateLed_ON(uint8_t parseNum) {   //点亮单色调颜色
  switch (parseNum) {
    case 0: fill_solid(leds, NUM_LEDS, CRGB::Crimson);              FastLED.show(); break;
    case 1: fill_solid(leds, NUM_LEDS, CRGB::Aqua);                 FastLED.show(); break;
    case 2: fill_solid(leds, NUM_LEDS, CRGB::Amethyst);             FastLED.show(); break;
    case 3: fill_solid(leds, NUM_LEDS, CRGB::Blue);                 FastLED.show(); break;
    case 4: fill_solid(leds, NUM_LEDS, CRGB::Chartreuse);           FastLED.show(); break;
    case 5: fill_solid(leds, NUM_LEDS, CRGB::DarkOrange);           FastLED.show(); break;
    case 6: fill_solid(leds, NUM_LEDS, CRGB::DeepPink);             FastLED.show(); break;
    case 7: fill_solid(leds, NUM_LEDS, CRGB::GhostWhite);           FastLED.show(); break;
    case 8: fill_solid(leds, NUM_LEDS, CRGB::Gold);                 FastLED.show(); break;
    case 9: fill_solid(leds, NUM_LEDS, CRGB::GreenYellow);          FastLED.show(); break;
    case 10: fill_solid(leds, NUM_LEDS, CRGB::MediumSpringGreen);   FastLED.show(); break;
  }
  FastLED.show();
}

void stateLed_OFF() {
  fill_solid(leds, NUM_LEDS, CRGB::Black);
  FastLED.show();
}

void dynamicLED(uint8_t paletteNum, uint8_t colorIndex) {
  switch (paletteNum) {
    case 0: gradientflowingLED(); break;
    case 1: FillLEDsFromPaletteColors(colorIndex); break;
  }
}

void gradientflowingLED() {
  for (int i = 0; i < NUM_LEDS; i++) {
    fill_solid(leds + i, 1, myHSVcolor);
    FastLED.show();
    myHSVcolor.h += 10;
    delay(50);

    fill_solid(leds + i, 1, CRGB::Black);
    FastLED.show();
    delay(50);
  }

  for (int i = NUM_LEDS; i > 0; i--) {
    fill_solid(leds + i, 1, myHSVcolor);
    FastLED.show();
    myHSVcolor.h += 10;
    delay(50);

    fill_solid(leds + i, 1, CRGB::Black);
    FastLED.show();
    delay(50);
  }
}

void FillLEDsFromPaletteColors(uint8_t colorIndex)
{
  for (int i = 0; i < chromatism; i++) {
    colorIndex++;
    for ( int j = 0; j < NUM_LEDS; ++j) {
      leds[j] = ColorFromPalette(RainbowColors_p, colorIndex, 255, LINEARBLEND);
      colorIndex += 3;
      FastLED.show();
      FastLED.delay(10);
    }
  }
  fill_solid(leds, NUM_LEDS, CRGB::Black);
  FastLED.show();
}