Android通过串口读取DS18B20温度传感器板子

心已赠人 2023-06-06 12:09 21阅读 0赞

最新在做安卓新零售终端，需要通过串口读取DS18B20温度传感器温度，我们是使用第三方温度传感器板子，我们安装厂家定义的协议发送查询数据命令，就会返回温度数组的串口命令，对串口的温度值进行解析即可得到温度，我写了一个Demo进行串口读温度测试，以下为测试的源码：

（1）MainActivity.java

package kyle.me.testz;
    
    import androidx.annotation.Nullable;
    import androidx.appcompat.app.AppCompatActivity;
    
    import android.os.Bundle;
    import android.util.Log;
    
    import com.aill.androidserialport.SerialPort;
    
    import java.io.File;
    import java.io.IOException;
    import java.io.InputStream;
    import java.io.OutputStream;
    
    public class MainActivity extends AppCompatActivity {
        private final String TAG = MainActivity.class.getSimpleName();
    
        private SerialPort serialPort;
    
        private InputStream mInputStream;
        private OutputStream mOutputStream;
    
        private final int BAUDRATE = 9600;                          // 波特率
        private final String SERIALPORT_NO3 = "/dev/ttyS4";         // 串口号4
        private final String QUERY_TEMP_CMD = "010300000001840a";   // 查询温度命令
    
        @Override
        protected void onCreate(@Nullable Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
    
            initSerialPort();
            new Thread(new ReadSerialPortTempThread()).start();
        }
    
        private class ReadSerialPortTempThread implements Runnable {
            @Override
            public void run() {
                while (true) {
                    try {
                        final String getTemp = ReadSerialPortTemp();
                        Log.d(TAG, "getTemp =" + getTemp);
                        Thread.sleep(1000);
                        Log.d(TAG, "sleep 1000!");
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            }
        }
    
        public String ReadSerialPortTemp() {
            final String readTemp = ReadSerialPortTempCmd();
            if (readTemp.equals("")) {
                Log.d(TAG, "read temp error!");
                return "";
            } else {
                final String parserReadTemp = parserSerialPortHexTemp(readTemp);
                return parserReadTemp;
            }
        }
    
        private String ReadSerialPortTempCmd() {
            final String tempSendCmd = QUERY_TEMP_CMD;
            if (tempSendCmd != null && !tempSendCmd.equals("")) {
                int size;
                byte[] sendBuff = fromHexString(tempSendCmd);
                byte revBuff[] = new byte[1024];
                String tempRevCmd = "";
                try {
                    mOutputStream.write(sendBuff, 0, sendBuff.length);
                    try {
                        Thread.sleep(10);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                    try {
                        if (mInputStream == null) {
                            return "";
                        }
                        size = mInputStream.read(revBuff);
                        Log.d(TAG, "size =" + size);
                        if (size > 0) {
                            for (int i = 0; i < size; i++) {
                                tempRevCmd += hexToDecimal(revBuff[i]);
                            }
                        }
                        Log.d(TAG, "resultString =" + tempRevCmd);
    
                        if (tempRevCmd.length() == 14) {
                            Log.d(TAG, "return tempRevCmd!");
                            return tempRevCmd;
                        } else {
                            Log.d(TAG, "no return tempRevCmd!");
                            return "";
                        }
                    } catch (Exception e) {
                        e.printStackTrace();
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                } finally {
    
                }
            }
            return "";
        }
    
        private String parserSerialPortHexTemp(String hexTempCmd) {
            if ((!hexTempCmd.equals("")) || (!hexTempCmd.equals("8000"))) {
                final String hexTemp = hexTempCmd.substring(6, 10);
                Log.d(TAG, "newResultString = " + hexTemp);
                double temp = parseHex4(hexTemp) / 10;
                Log.d(TAG, "temp =" + temp);
                return String.valueOf(temp);
            } else {
                return "";
            }
        }
    
        public void initSerialPort() {
            try {
                serialPort = new SerialPort(new File(SERIALPORT_NO3), BAUDRATE, 0);
                mInputStream = serialPort.getInputStream();
                mOutputStream = serialPort.getOutputStream();
            } catch (Exception e) {
                e.printStackTrace();
                Log.d(TAG, "打开串口失败!");
            }
        }
    
        public void deInitSerialPort() {
            try {
                try {
                    mOutputStream.close();
                    mInputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
                serialPort.close();
            } catch (Exception e) {
                e.printStackTrace();
                Log.d(TAG, "关闭串口失败!");
            }
        }
    
        private static double parseHex4(String num) {
            if (num.length() != 4) {
                throw new NumberFormatException("Wrong length: " + num.length() + ", must be 4.");
            }
            int ret = Integer.parseInt(num, 16);
            ret = ((ret & 0x8000) > 0) ? (ret - 0x10000) : (ret);
            return (double) ret;
        }
    
        private String hexToDecimal(byte oneByte) {
            String str = "";
            int h = (oneByte >>> 4) & 0xF;
            int l = oneByte & 0xF;
            char ch = (char) ((h < 10) ? ('0' + h) : ('A' + h - 10));
            char cl = (char) ((l < 10) ? ('0' + l) : ('A' + l - 10));
            str = "";
            str += ch;
            str += cl;
            return str;
        }
    
        private static byte[] fromHexString(String hexString) {
            if (null == hexString || "".equals(hexString.trim())) {
                return new byte[0];
            }
            byte[] bytes = new byte[hexString.length() / 2];
            String hex;
            for (int i = 0; i < hexString.length() / 2; i++) {
                hex = hexString.substring(i * 2, i * 2 + 2);
                bytes[i] = (byte) Integer.parseInt(hex, 16);
            }
            return bytes;
        }
    }

（2）app/build.gradle

apply plugin: 'com.android.application'
    
    android {
        compileSdkVersion 29
        buildToolsVersion "29.0.0"
        defaultConfig {
            applicationId "kyle.me.testz"
            minSdkVersion 19
            targetSdkVersion 29
            versionCode 1
            versionName "1.0"
            testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
        }
        buildTypes {
            release {
                minifyEnabled false
                proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
            }
        }
    }
    
    dependencies {
        implementation fileTree(dir: 'libs', include: ['*.jar'])
        implementation 'androidx.appcompat:appcompat:1.1.0'
        implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
        testImplementation 'junit:junit:4.12'
        androidTestImplementation 'androidx.test:runner:1.2.0'
        androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'
    
        implementation 'com.aill:AndroidSerialPort:1.0.8'
    }

（3）运行结果

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzE5MDA0NjI3_size_16_color_FFFFFF_t_70][]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzE5MDA0NjI3_size_16_color_FFFFFF_t_70]: /images/20230601/c0d9507911684a4db59ea1beffd80445.png