From 9205ef1ef53676882cf95b83c588bda60bb9931e Mon Sep 17 00:00:00 2001
From: Will Bradley <will@zyphon.com>
Date: Thu, 13 Feb 2025 11:41:05 -0800
Subject: [PATCH] Use deep sleep to save battery

---
 MultiSoilMoistureSensor.ino | 34 ++++++++++++++++++++++++++--------
 1 file changed, 26 insertions(+), 8 deletions(-)

diff --git a/MultiSoilMoistureSensor.ino b/MultiSoilMoistureSensor.ino
index 3d5b531..861fee4 100644
--- a/MultiSoilMoistureSensor.ino
+++ b/MultiSoilMoistureSensor.ino
@@ -12,7 +12,8 @@ EspMQTTClient client(
   "espmqtt"      // Client name that uniquely identify your device
 );
 
-#define reportingInterval 10000 // how often to sample/publish, in milliseconds
+#define maxUptime 60*1000 // how long to stay awake to measure and report before sleeping
+#define reportingInterval 10*60*1000 // how often to sample/publish, in milliseconds
 #define PIN_RESET 4
 #define LED_BUILTIN 0 // ESP32
 //#define LED_BUILTIN 13 // Teensy
@@ -28,6 +29,7 @@ int pin_SDA = 15;
 int pin_SCL = 5;
 
 unsigned long last_run = 0;
+bool useOled = true;
 
 void onConnectionEstablished() {
   client.publish("esp/status", "{\"status\": \"connected\"}");
@@ -51,9 +53,12 @@ void setup() {
   Wire.begin(pin_SDA, pin_SCL); //Qwiic Pro Mini
   if (!oled.begin()){
     Serial.println("Failed to initialize OLED");
+    useOled = false;
   }
 
   delay(1000); // Delay 1000 ms
+
+  esp_sleep_enable_timer_wakeup(10*60*1000*1000); // 10 minutes
 }
 
 // 0-based index read
@@ -78,9 +83,9 @@ bool readAndPublishSensor(int i) {
   Serial.print(" - ");
   Serial.println(sensorText);
 
-  // show on LED with 1-based plant number and 0-100%
+  // show on OLED with 1-based plant number and 0-100%
   snprintf(sensorText, 31, "%d: %d%%", n, sensorPercent);
-  oled.text(0, n*8, sensorText);
+  if (useOled) oled.text(0, n*8, sensorText);
   
   return sensorPercent > 50; // over 50% is true/good, under 50% is false/bad
 }
@@ -88,9 +93,12 @@ bool readAndPublishSensor(int i) {
 // the loop function runs over and over again forever
 void loop() {
   unsigned long time_trigger = millis();
-  if (last_run == 0 || time_trigger-last_run > reportingInterval) {
-    oled.erase();
-    oled.text(0, 0, "Water:");
+  // report on first run
+  if (last_run == 0) {
+    if (useOled) {
+      oled.erase();
+      oled.text(0, 0, "Water:");
+    }
     bool showLed = false;
     // read + output plant sensors
     for(int i=0;i<(sizeof(plantPin)/sizeof(plantPin[0]));i++){
@@ -105,9 +113,19 @@ void loop() {
       digitalWrite(LED_BUILTIN, LOW);
     }
 
-    oled.display();
+    if (useOled) oled.display();
     last_run = time_trigger;
   }
-  client.loop();
+  if (time_trigger > maxUptime) {
+    Serial.print("Sleeping now.");
+    delay(1000);
+    Serial.flush();
+    esp_deep_sleep_start();
+    Serial.print("You can't see this because I'm asleep.");
+  }
+  if (time_trigger-last_run > reportingInterval) {
+    Serial.print("Stayed online for a full reporting interval without sleeping or resetting, something is wrong");
+  }
+  client.loop(); // Do MQTT work
   sleep(1);
 }