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https://github.com/m5stack/M5AtomU.git
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sean
64 lines
2.3 KiB
Arduino
64 lines
2.3 KiB
Arduino
/*
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*******************************************************************************
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* Copyright (c) 2021 by M5Stack
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* Equipped with Atom-Lite/Matrix sample source code
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* 配套 Atom-Lite/Matrix 示例源代码
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* Visit the website for more information：https://docs.m5stack.com/en/products
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* 获取更多资料请访问：https://docs.m5stack.com/zh_CN/products
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*
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* describe：Hall sensor. 霍尔传感器
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* date：2021/7/28
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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 <M5Atom.h>
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#define RANGE 320
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float HallOffset =
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0; // Store the initial value of magnetic force. 存储磁力的初值
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float LowPassFilteredValue = 0;
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float ESP32_hallRead() // ESP32 hall value read. ESP32霍尔值读取
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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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void setup() {
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M5.begin(); // Init M5Atom. 初始化M5Atom
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Serial.println("ESP32 Hall sensor:"); // Serial printout. 串口打印输出
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HallOffset =
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ESP32_hallRead(); // callibrate the output value to the magnetic field
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// at start up. 在启动时将输出值校准到磁场
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}
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void showSignal() {
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int n;
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for (n = 0; n < RANGE;
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n++) // Within the horizontal resolution, each pixel is drawn
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// according to the calculated magnetic force
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{ // 在此范围内,根据计算得到的磁力大小
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float value =
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ESP32_hallRead() - HallOffset; // Reduce the influence of own
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// magnetism. 减少自身磁力的影响
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LowPassFilteredValue += (value - LowPassFilteredValue) * 0.05;
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Serial.printf("Low Pass Filtered Value:%d\n",
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(int)LowPassFilteredValue);
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if (n > 0) {
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Serial.printf("Magnetic value:%.2f\n\n", value);
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}
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}
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}
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void loop(void) {
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showSignal();
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delay(200);
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}
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