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Tinyu
90 lines
3.0 KiB
Arduino
90 lines
3.0 KiB
Arduino
/*
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*******************************************************************************
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* Copyright (c) 2021 by M5Stack
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* Equipped with M5Core sample source code
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* 配套 M5Core 示例源代码
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* Visit the website for more information：https://docs.m5stack.com/en/core/gray
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* 获取更多资料请访问：https://docs.m5stack.com/zh_CN/core/gray
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*
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* describe：Hall sensor. 霍尔传感器
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* date：2021/7/26
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*******************************************************************************
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The ESP32 MCU has build in Hall sensor. ESP32 MCU内置霍尔传感器
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It is not very suscescible but if you bring a magnet close to the
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upper screen you will see the influence on the measurement.
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In this example we use some low pass filters to get rid of the noise.
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*/
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#include <M5Stack.h>
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#define M5STACKFIRE_SPEAKER_PIN 34 // speaker DAC, only 8 Bit. 扬声器的管脚
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#define HORIZONTAL_RESOLUTION 320
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#define VERTICAL_RESOLUTION 240
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#define POSITION_OFFSET_Y 20
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uint16_t oldSignal[HORIZONTAL_RESOLUTION];
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uint16_t adcBuffer[HORIZONTAL_RESOLUTION];
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float ESP32_hallRead()
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{
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float value = 0;
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int count = 400;
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// mean value filter. 数据低通滤波器
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for (int n = 0; n < count; n++) value += hallRead();
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return value / count * 10;
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}
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float HallOffset = 0;
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void setup()
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{
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dacWrite(M5STACKFIRE_SPEAKER_PIN, 0); // make sure that the speaker is quite. 必须确保扬声器处于关闭状态
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M5.begin(); //Init M5Stack. 初始化M5Stack
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M5.Power.begin(); //Init power 初始化电源模块
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M5.Lcd.setTextSize(2); //Set the font size to 2. 设置字体大小为2
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M5.Lcd.println("ESP32 Hall sensor:"); //Screen printout. 屏幕打印输出
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HallOffset = ESP32_hallRead(); // callibrate the output value to the magnetic field at start up. 在启动时将输出值校准到磁场
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}
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float LowPassFilteredValue=0;
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void showSignal()
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{
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int n;
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int oldx;
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int oldy;
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int oldSig;
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int x, y;
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for (n = 0; n < HORIZONTAL_RESOLUTION; n++) //在水平分辨率内,每个像素点根据计算得到的磁力大小绘制
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{ //Within the horizontal resolution, each pixel is drawn according to the calculated magnetic force
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x = n;
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float value = ESP32_hallRead()- HallOffset;
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LowPassFilteredValue+=(value-LowPassFilteredValue)*0.05;
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M5.Lcd.setCursor(220, 1);
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M5.Lcd.print((int)LowPassFilteredValue);M5.Lcd.print(" ");
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y = map(value , -127, 127, VERTICAL_RESOLUTION, POSITION_OFFSET_Y);
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if (n > 0)
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{
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// delete old line element. 删除上次画的线
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M5.Lcd.drawLine(oldx , oldSig, x, oldSignal[n], BLACK );
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// draw new line element. 画新的线
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if (n < HORIZONTAL_RESOLUTION - 1) // don't draw last element because it would generate artifacts. 不能绘制最后一个像素
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{
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M5.Lcd.drawLine(oldx,oldy,x,y, GREEN);
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}
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}
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oldx = x;
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oldy = y;
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oldSig = oldSignal[n];
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oldSignal[n] = y;
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}
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}
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void loop(void)
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{
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showSignal();
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}
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