YW51 module library for calculating PM2.5

Dependencies:   SoftSerial

Revision:
0:1abc1344f5eb
Child:
1:9b8788ea7c85
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/YW51.cpp	Tue Feb 19 14:24:36 2019 +0000
@@ -0,0 +1,104 @@
+/* YW51 module Library
+ *
+ * Copyright (c) 2019, 黃博鈞, National Taiwan University
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+#include "YW51.h"
+
+YW51::YW51(PinName tx, PinName rx, int Baud) : _YW51(tx, rx)
+{
+    _YW51.baud(Baud);
+}
+
+int YW51::readData()
+{
+    double vo;
+
+    getline();
+    if(msg[0]+ msg[1]+ msg[2]+ msg[3] == msg[4]) {
+        vo = (msg[0] * 256.0 + msg[1])* 2.5 / 1024.0;
+        pm = findK(vo) * vo;
+        return 1;
+    } else {
+        return 0;
+    }
+}
+
+double YW51::ShowPM()
+{
+    return pm;
+
+}
+int YW51::findK(double vo)
+{
+    if(vo <= 0.045) {
+        return 200;
+    } else if(vo > 0.046 && vo < 0.048) {
+        return 400;
+    } else if(vo > 0.049 && vo < 0.051) {
+        return 600;
+    } else if(vo > 0.052 && vo < 0.054) {
+        return 750;
+    } else if(vo > 0.055 && vo < 0.058) {
+        return 900;
+    } else if(vo > 0.059 && vo < 0.064) {
+        return 1000;
+    } else if(vo > 0.065 && vo < 0.070) {
+        return 1250;
+    } else if(vo > 0.071 && vo < 0.075) {
+        return 1400;
+    } else if(vo > 0.076 && vo < 0.080) {
+        return 1700;
+    } else if(vo > 0.081 && vo < 0.085) {
+        return 1800;
+    } else if(vo > 0.086 && vo < 0.090) {
+        return 1900;
+    } else if(vo > 0.091 && vo < 0.100) {
+        return 2000;
+    } else if(vo > 0.101 && vo < 0.110) {
+        return 2200;
+    } else if(vo >= 0.111) {
+        return 3000;
+    }
+}
+int YW51::PMStage(double pm)
+{
+    if(pm <= 35) {
+        return 1;//good
+    } else if(pm > 35 && pm <= 53 ) {
+        return 2; //medium
+    } else if(pm > 53 && pm <= 70 ) {
+        return 3;//bad
+    } else {
+        return 4;//very bad
+    }
+}
+void YW51::getline()
+{
+    while(_YW51.getc() != 170);    // wait for the start of a line
+    for(int i = 0; i < 6; i++) {
+        msg[i] = _YW51.getc();
+        if(msg[i] == 255) {
+            return;
+        }
+    }
+    error("Overflowed message limit");
+}
+