start of data logging to sd card

3 files changed, 69 insertions, 2 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;
+    }
+  }
+};
diff --git a/display.h b/display.h
index 8e9616f..b6dd433 100644
--- a/display.h
+++ b/display.h
@@ -42,6 +42,10 @@ public:
   }
 };
 
+/*
+  most of this comes from
+  https://github.com/Xinyuan-LilyGO/LilyGo-T5-Epaper-Series/blob/master/examples/GxEPD_Partial_Update_Example/GxEPD_Partial_Update_Example.ino
+ */
 class Display {
 private:
   GxIO_Class io;
diff --git a/main.ino b/main.ino
index 180f5cd..9fcabbe 100644
--- a/main.ino
+++ b/main.ino
@@ -4,6 +4,7 @@
 #include "data.h"
 #include "battery.h"
 #include "display.h"
+#include "datalog.h"
 #include "co2.h"
 #include "pm.h"
 
@@ -14,6 +15,7 @@ CO2 co2;
 SensorData data;
 
 Display display;
+DataLog datalog;
 
 void setup() {
   Serial.begin(115200);
@@ -27,6 +29,10 @@ void setup() {
   display.start();
   display.show(&data);
 
+  // I think this has to come after the display.start(), they may both
+  // use the same SPI thing
+  datalog.start();
+
   battery.start();
   co2.start();
   pm.start();
@@ -42,7 +48,10 @@ void loop() {
   if (pm.dataReady()) { changed = true; pm.read(&data); }
   if (co2.dataReady()) { changed = true; co2.read(&data); }
 
-  if (changed) display.show(&data);
-  
+  if (changed) {
+    display.show(&data);
+    datalog.show(&data);
+  }
+
   delay(5000);
 }