From f38e6fe6aee6ec45dc75475007c90ef70c66446e Mon Sep 17 00:00:00 2001
From: Thomas Kolb <cfr34k-git@tkolb.de>
Date: Fri, 3 Jan 2025 22:45:10 +0100
Subject: [PATCH] Add support for the BME680 sensor

---
 data/htdocs/index.html |  43 ++++++++++---
 include/WebServer.h    |   4 +-
 platformio.ini         |   1 +
 src/WebServer.cpp      |  12 +++-
 src/main.cpp           | 135 +++++++++++++++++++++++++++++++++++------
 5 files changed, 165 insertions(+), 30 deletions(-)

diff --git a/data/htdocs/index.html b/data/htdocs/index.html
index e168391..f20c951 100644
--- a/data/htdocs/index.html
+++ b/data/htdocs/index.html
@@ -7,20 +7,27 @@
 	<script type="text/javascript">
 		function updateSensorTable(sensordata)
 		{
-			elements = ['temperature', 'humidity', 'co2'];
+			scd30_elements = ['temperature', 'humidity', 'co2'];
 
-
-			elements.forEach(function(item, index) {
+			scd30_elements.forEach(function(item, index) {
 				elem = document.getElementById('scd30_' + item);
 				val = sensordata['scd30'][item];
 				elem.textContent = val.toFixed(2);
 			});
+
+			bme680_elements = ['temperature', 'humidity', 'pressure', 'gas_resistance'];
+
+			bme680_elements.forEach(function(item, index) {
+				elem = document.getElementById('bme680_' + item);
+				val = sensordata['bme680'][item];
+				elem.textContent = val.toFixed(2);
+			});
 		}
 
 		function setup()
 		{
 			getSensorData(updateSensorTable);
-			setInterval(function() { getSensorData(updateSensorTable) }, 60000);
+			setInterval(function() { getSensorData(updateSensorTable) }, 30000);
 		}
 	</script>
 	<style>
@@ -43,24 +50,40 @@
 	<table>
 		<tr>
 			<th>Sensor</th>
-			<th>Messwert</th>
+			<th>SCD30</th>
+			<th>BME680</th>
 			<th>Einheit</th>
 		</tr>
 		<tr>
-			<td>SCD30 CO₂</td>
-			<td class="value" id="scd30_co2">----,--</td>
+			<td>CO₂</td>
+			<td class="value" id="scd30_co2">---,--</td>
+			<td class="value" id="bme680_co2">---,--</td>
 			<td>ppm</td>
 		</tr>
 		<tr>
-			<td>SCD30 Temperatur</td>
+			<td>Temperatur</td>
 			<td class="value" id="scd30_temperature">-,--</td>
+			<td class="value" id="bme680_temperature">-,--</td>
 			<td>°C</td>
 		</tr>
 		<tr>
-			<td>SCD30 Luftfeuchtigkeit</td>
-			<td class="value" id="scd30_humidity">-,--</td>
+			<td>Luftfeuchtigkeit</td>
+			<td class="value" id="scd30_humidity">--,--</td>
+			<td class="value" id="bme680_humidity">--,--</td>
 			<td>%rH</td>
 		</tr>
+		<tr>
+			<td>Luftdruck</td>
+			<td class="value" id="scd30_pressure">---,--</td>
+			<td class="value" id="bme680_pressure">---,--</td>
+			<td>hPa</td>
+		</tr>
+		<tr>
+			<td>Gaswiderstand</td>
+			<td class="value" id="scd30_gas_resistance">---,--</td>
+			<td class="value" id="bme680_gas_resistance">---,--</td>
+			<td>kΩ</td>
+		</tr>
 	</table>
 </body>
 </html>
diff --git a/include/WebServer.h b/include/WebServer.h
index d4256a7..3c728d4 100644
--- a/include/WebServer.h
+++ b/include/WebServer.h
@@ -1,6 +1,7 @@
 #pragma once
 
 #include <Adafruit_SCD30.h>
+#include <Adafruit_BME680.h>
 
 #include <HTTPRequest.hpp>
 #include <HTTPResponse.hpp>
@@ -12,7 +13,7 @@
 class WebServer
 {
     public:
-        bool start(Adafruit_SCD30 *scd30);
+        bool start(Adafruit_SCD30 *scd30, Adafruit_BME680 *bme680);
 
         static WebServer &instance(void)
         {
@@ -24,6 +25,7 @@ class WebServer
         httpsserver::HTTPServer *m_server;
 
         Adafruit_SCD30  *m_scd30;
+        Adafruit_BME680 *m_bme680;
 
         WebServer(void);
 
diff --git a/platformio.ini b/platformio.ini
index dbf71cb..6085cce 100644
--- a/platformio.ini
+++ b/platformio.ini
@@ -19,6 +19,7 @@ monitor_speed = 115200
 lib_deps =
 	zinggjm/GxEPD2@^1.5.7
 	adafruit/Adafruit SCD30@^1.0.11
+	adafruit/Adafruit BME680 Library@^2.0.5
 	SPI
 	Wire
 	NTPClient
diff --git a/src/WebServer.cpp b/src/WebServer.cpp
index 8024d37..83a41f4 100644
--- a/src/WebServer.cpp
+++ b/src/WebServer.cpp
@@ -71,6 +71,15 @@ void WebServer::handleReadout(httpsserver::HTTPRequest *req, httpsserver::HTTPRe
     res->print(instance().m_scd30->relative_humidity);
     res->print(", \"temperature\": ");
     res->print(instance().m_scd30->temperature);
+    res->print("},");
+    res->print("\"bme680\": {\"pressure\": ");
+    res->print(instance().m_bme680->pressure/100.0);
+    res->print(", \"humidity\": ");
+    res->print(instance().m_bme680->humidity);
+    res->print(", \"temperature\": ");
+    res->print(instance().m_bme680->temperature);
+    res->print(", \"gas_resistance\": ");
+    res->print(instance().m_bme680->gas_resistance / 1000.0);
     res->println("}}");
 }
 
@@ -155,9 +164,10 @@ void WebServer::serverTask(void *arg)
     Serial.println("[server] Server died?! This should never happen.");
 }
 
-bool WebServer::start(Adafruit_SCD30 *scd30)
+bool WebServer::start(Adafruit_SCD30 *scd30, Adafruit_BME680 *bme680)
 {
     m_scd30 = scd30;
+    m_bme680 = bme680;
 
     xTaskCreatePinnedToCore(
         WebServer::serverTask, /* Task function. */
diff --git a/src/main.cpp b/src/main.cpp
index ebc9d96..73f1937 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -1,5 +1,6 @@
 #include <Arduino.h>
 #include <Adafruit_SCD30.h>
+#include <Adafruit_BME680.h>
 
 #include <WiFi.h>
 #include <WiFiMulti.h>
@@ -19,8 +20,10 @@
 #include <epaper.h>
 
 Adafruit_SCD30  scd30;
+Adafruit_BME680 bme680;
 
 static timeseries_t ts_scd30_co2, ts_scd30_temperature, ts_scd30_humidity;
+static timeseries_t ts_bme680_temperature, ts_bme680_humidity, ts_bme680_pressure, ts_bme680_gas_resistance;
 
 static WiFiMulti wiFiMulti;
 static bool      wiFiConnectedToStation;
@@ -94,6 +97,10 @@ void initSCD30(void)
 	timeseries_init(&ts_scd30_co2, timeClient.getEpochTime(), 15, "ppm", "%.1f");
 	timeseries_init(&ts_scd30_temperature, timeClient.getEpochTime(), 15, "°C", "%.1f");
 	timeseries_init(&ts_scd30_humidity, timeClient.getEpochTime(), 15, "%", "%.1f");
+	timeseries_init(&ts_bme680_temperature, timeClient.getEpochTime(), 15, "°C", "%.1f");
+	timeseries_init(&ts_bme680_humidity, timeClient.getEpochTime(), 15, "%", "%.1f");
+	timeseries_init(&ts_bme680_pressure, timeClient.getEpochTime(), 15, "hPa", "%.1f");
+	timeseries_init(&ts_bme680_gas_resistance, timeClient.getEpochTime(), 15, "kOhm", "%.1f");
 
 	// Try to initialize!
 	if (!scd30.begin()) {
@@ -102,8 +109,7 @@ void initSCD30(void)
 	}
 	Serial.println("scd30: SCD30 Found!");
 
-	// TODO: check what this actually resets. Maybe also the calibration?
-	scd30.reset();
+	scd30.reset(); // note: does not reset the calibration
 
 	if (!scd30.setMeasurementInterval(15)){ // seconds
 		Serial.println("scd30: Failed to set measurement interval");
@@ -145,6 +151,24 @@ void initSCD30(void)
 }
 
 
+static void initBME680(void)
+{
+	if (!bme680.begin()) {
+		Serial.println(F("Could not find a valid BME680 sensor, check wiring!"));
+		while (1) {
+			delay(10);
+		}
+	}
+
+	// Set up oversampling and filter initialization
+	bme680.setTemperatureOversampling(BME680_OS_8X);
+	bme680.setHumidityOversampling(BME680_OS_2X);
+	bme680.setPressureOversampling(BME680_OS_4X);
+	bme680.setIIRFilterSize(BME680_FILTER_SIZE_3);
+	bme680.setGasHeater(320, 150); // 320*C for 150 ms
+}
+
+
 static void draw_epaper_initial_callback(GxEPD2_DISPLAY_CLASS<GxEPD2_DRIVER_CLASS, MAX_HEIGHT(GxEPD2_DRIVER_CLASS)> *display)
 {
 	display->setRotation(1);
@@ -212,16 +236,19 @@ void setup(void)
 	wifi_setup();
 
 	initSCD30();
+	initBME680();
 	epaper_init();
 
 	epaper_draw_and_hibernate(draw_epaper_initial_callback, false);
 
-	WebServer::instance().start(&scd30);
+	WebServer::instance().start(&scd30, &bme680);
 }
 
 
 static void draw_epaper_callback(GxEPD2_DISPLAY_CLASS<GxEPD2_DRIVER_CLASS, MAX_HEIGHT(GxEPD2_DRIVER_CLASS)> *display)
 {
+	const int16_t line_height = 75;
+
 	display->setRotation(1);
 	display->setTextColor(GxEPD_BLACK);
 
@@ -248,10 +275,10 @@ static void draw_epaper_callback(GxEPD2_DISPLAY_CLASS<GxEPD2_DRIVER_CLASS, MAX_H
 	display->setFont(&FreeSans12pt7b);
 	display->print(" ppm");
 
-	epaper_plot(150, 5, 150, 65, &ts_scd30_co2, 900);
+	epaper_plot(150, 0*line_height + 5, 150, 65, &ts_scd30_co2, 900);
 
 	// second line: temperature
-	y = 75 + FreeSans12pt7b.yAdvance*3/4;
+	y = 1*line_height + FreeSans12pt7b.yAdvance*3/4;
 	display->setCursor(0, y);
 
 	display->setFont(&FreeSans12pt7b);
@@ -261,7 +288,7 @@ static void draw_epaper_callback(GxEPD2_DISPLAY_CLASS<GxEPD2_DRIVER_CLASS, MAX_H
 	display->setCursor(0, y);
 
 	display->setFont(&FreeSansBold12pt7b);
-	display->print(scd30.temperature, 2);
+	display->print(bme680.temperature, 2);
 
 	display->setFont(&FreeSans12pt7b);
 	display->print(" ");
@@ -277,10 +304,10 @@ static void draw_epaper_callback(GxEPD2_DISPLAY_CLASS<GxEPD2_DRIVER_CLASS, MAX_H
 	display->setCursor(cursor_x, stored_baseline_y);
 	display->print("C");
 
-	epaper_plot(150, 80, 150, 65, &ts_scd30_temperature, 900);
+	epaper_plot(150, 1*line_height + 5, 150, 65, &ts_bme680_temperature, 900);
 
-	// second line: Humidity
-	y = 150 + FreeSans12pt7b.yAdvance*3/4;
+	// third line: Humidity
+	y = 2*line_height + FreeSans12pt7b.yAdvance*3/4;
 	display->setCursor(0, y);
 
 	display->setFont(&FreeSans12pt7b);
@@ -290,21 +317,57 @@ static void draw_epaper_callback(GxEPD2_DISPLAY_CLASS<GxEPD2_DRIVER_CLASS, MAX_H
 	display->setCursor(0, y);
 
 	display->setFont(&FreeSansBold12pt7b);
-	display->print(scd30.relative_humidity, 1);
+	display->print(bme680.humidity, 1);
 
 	display->setFont(&FreeSans12pt7b);
 	display->print(" %rH");
 
-	epaper_plot(150, 155, 150, 65, &ts_scd30_humidity, 900);
+	epaper_plot(150, 2*line_height + 5, 150, 65, &ts_bme680_humidity, 900);
 
-	y = 225 + FreeSans12pt7b.yAdvance*3/4;
+	// fourth line: Pressure
+	y = 3*line_height + FreeSans12pt7b.yAdvance*3/4;
+	display->setCursor(0, y);
+
+	display->setFont(&FreeSans12pt7b);
+	display->print("Druck: ");
+
+	y += FreeSans12pt7b.yAdvance;
+	display->setCursor(0, y);
+
+	display->setFont(&FreeSansBold12pt7b);
+	display->print(bme680.pressure / 100.0, 1);
+
+	display->setFont(&FreeSans12pt7b);
+	display->print(" hPa");
+
+	epaper_plot(150, 3*line_height + 5, 150, 65, &ts_bme680_pressure, 900);
+
+	// fifth line: Gas resistance
+	y = 4*line_height + FreeSans12pt7b.yAdvance*3/4;
+	display->setCursor(0, y);
+
+	display->setFont(&FreeSans12pt7b);
+	display->print("Gas: ");
+
+	y += FreeSans12pt7b.yAdvance;
+	display->setCursor(0, y);
+
+	display->setFont(&FreeSansBold12pt7b);
+	display->print(bme680.gas_resistance * 1e-3, 2);
+
+	display->setFont(&FreeSans12pt7b);
+	display->print(" kOhm");
+
+	epaper_plot(150, 4*line_height + 5, 150, 65, &ts_bme680_gas_resistance, 900);
+
+	y = 5*line_height + FreeSans12pt7b.yAdvance*3/4;
 	display->setCursor(0, y);
 
 	display->setFont(&FreeSans12pt7b);
 	display->print("Aktualisiert: ");
 
-	y += FreeSans12pt7b.yAdvance;
-	display->setCursor(0, y);
+	//y += FreeSans12pt7b.yAdvance;
+	//display->setCursor(0, y);
 
 	display->setFont(&FreeSansBold12pt7b);
 	display->print(timeClient.getFormattedTime());
@@ -318,7 +381,12 @@ static void upload_data(void)
 	String json_string = String("{"
 			"\"scd30_co2\":") + scd30.CO2
 			+ ", \"scd30_temperature\":" + scd30.temperature
-			+ ", \"scd30_humidity\":" + scd30.relative_humidity + "}";
+			+ ", \"scd30_humidity\":" + scd30.relative_humidity
+			+ ", \"bme680_temperature\":" + bme680.temperature
+			+ ", \"bme680_humidity\":" + bme680.humidity
+			+ ", \"bme680_pressure\":" + bme680.pressure
+			+ ", \"bme680_gas_resistance\":" + bme680.gas_resistance
+			+ "}";
 
 	// send the data to graphite
 	HTTPClient client;
@@ -364,6 +432,32 @@ void loop(void)
 			first_scd30_readout = false;
 		}
 
+		// read synchronously from the bme680. This takes some time (100s of
+		// milliseconds), but the SCD30 is running autonomously, so this does not
+		// disturb that measurement.
+		if(bme680.performReading()) {
+			timeseries_append(&ts_bme680_temperature, bme680.temperature);
+			timeseries_append(&ts_bme680_humidity, bme680.humidity);
+			timeseries_append(&ts_bme680_pressure, bme680.pressure / 100.0);
+			timeseries_append(&ts_bme680_gas_resistance, bme680.gas_resistance / 1000.0);
+
+			Serial.println("BME680:");
+			Serial.print("Temperature: ");
+			Serial.print(bme680.temperature, 3);
+			Serial.println(" °C");
+			Serial.print("Rel. humidity: ");
+			Serial.print(bme680.humidity, 2);
+			Serial.println(" %");
+			Serial.print("Pressure: ");
+			Serial.print(bme680.pressure / 100.0, 2);
+			Serial.println(" hPa");
+			Serial.print("Gas resistance: ");
+			Serial.print(bme680.gas_resistance);
+			Serial.println(" Ohm");
+			Serial.println("");
+		}
+
+		Serial.println("SCD30:");
 		Serial.print("CO2: ");
 		Serial.print(scd30.CO2, 3);
 		Serial.println(" ppm");
@@ -403,9 +497,14 @@ void loop(void)
 		epaper_draw_and_hibernate(draw_epaper_callback, false);
 		Serial.println("Display updated.");
 
-		timeseries_prune(&ts_scd30_humidity, 3600); // keep the last hour
-		timeseries_prune(&ts_scd30_temperature, 3600); // keep the last hour
-		timeseries_prune(&ts_scd30_co2, 3600); // keep the last hour
+		// keep the last hour
+		timeseries_prune(&ts_scd30_humidity, 3600);
+		timeseries_prune(&ts_scd30_temperature, 3600);
+		timeseries_prune(&ts_scd30_co2, 3600);
+		timeseries_prune(&ts_bme680_temperature, 3600);
+		timeseries_prune(&ts_bme680_humidity, 3600);
+		timeseries_prune(&ts_bme680_pressure, 3600);
+		timeseries_prune(&ts_bme680_gas_resistance, 3600);
 	}
 
 	delay(1000);