start of data logging to sd card

1 files changed, 54 insertions, 0 deletions

diff --git a/datalog.h b/datalog.h
new file mode 100644
index 0000000..39473e3
--- /dev/null
+++ b/datalog.h
@@ -0,0 +1,54 @@
+#pragma once
+
+#include <SD.h>
+#include <FS.h>
+
+#include "data.h"
+
+/*
+  most of this comes from
+  https://github.com/Xinyuan-LilyGO/LilyGo-T5-Epaper-Series/blob/master/examples/GxEPD_SD_1.02_Example/SD_Example.ino
+ */
+class DataLog {
+private:
+  SPIClass SDSPI;
+  File logfile;
+  char line[100];
+  uint8_t linesSinceLastFlush;
+  uint8_t flushThreshold;
+public:
+  DataLog(uint8_t ft=4) : SDSPI(VSPI), flushThreshold(ft) {}
+
+  void start() {
+    SDSPI.begin(SDCARD_SCLK, SDCARD_MISO, SDCARD_MOSI);
+    SD.begin(SDCARD_CS, SDSPI);
+    logfile = SD.open("air-quality.csv",FILE_APPEND,true);
+    linesSinceLastFlush=0;
+  }
+
+  void show(const SensorData *data) {
+    sprintf(
+            line,
+            //milli  co2   temp    humid   pm1     pm2.5   pm4     pm10   battery
+            "% 5lu, % 5u, % 5.1f, % 5.1f, % 6.1f, % 6.1f, % 6.1f, % 6.1f, % 5.2f\n",
+            millis()/1000,
+
+            data->co2,
+            data->temperature,
+            data->humidity,
+
+            data->pm.mc_1p0,
+            max(0.0f,data->pm.mc_2p5 - data->pm.mc_1p0),
+            max(0.0f,data->pm.mc_4p0 - data->pm.mc_2p5),
+            max(0.0f,data->pm.mc_10p0 - data->pm.mc_4p0),
+
+            data->batteryVoltage
+            );
+    logfile.write((uint8_t *)line,65);
+    Serial.write(line);
+    if (++linesSinceLastFlush > flushThreshold) {
+      logfile.flush();
+      linesSinceLastFlush=0;
+    }
+  }
+};