From 30b2902775ca0d360b4f3f86685f7a861e7df8fd Mon Sep 17 00:00:00 2001
From: Hendrik Langer <hendrik+dev@xd0.de>
Date: Thu, 8 Mar 2018 15:55:44 +0100
Subject: [PATCH] add powerbank stay awake code

---
 src/main.cpp | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 52 insertions(+), 1 deletion(-)

diff --git a/src/main.cpp b/src/main.cpp
index 3377f59..3f03ef6 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -7,6 +7,9 @@
 #include <Arduino.h>
 #include <ESP8266WiFi.h>
 #include <ESP8266WiFiMulti.h>
+extern "C" {
+#include <espnow.h>
+}
 
 #include <ESP8266HTTPClient.h>
 #include <ArduinoJson.h>
@@ -24,6 +27,7 @@ const char* server = "ingress.opensensemap.org";
 //const char* password = "";
 
 constexpr unsigned int postingInterval = 60000; //Uploadintervall in Millisekunden
+constexpr unsigned int powerbankInterval = 10000;
 
 //senseBox ID
 #define SENSEBOX_ID "5a9e9e38f55bff001a494877"
@@ -71,6 +75,18 @@ SDS011 sds;
 volatile unsigned long geiger_counts = 0;
 unsigned long geiger_previousMillis;
 
+struct __attribute__((packed)) SENSOR_DATA {
+  float temperature;
+  float humidity;
+  float pressure;
+  float temp2;
+  float p10;
+  float p25;
+  float radioactivity;
+  float voltage;
+  float rssi;
+} sd;
+
 void ICACHE_FLASH_ATTR sendValues() {
   float temperature = dht.readTemperature();
   float humidity = dht.readHumidity();
@@ -210,6 +226,36 @@ void ICACHE_FLASH_ATTR sendValues() {
 
 }
 
+void sendESPNOW() {
+  unsigned long espnowmillis = millis();
+  uint8_t remoteMac[] = {0x5C, 0xCF, 0x7F, 0x5, 0xFD, 0xF0};
+  #define WIFI_CHANNEL 1
+
+  WiFi.forceSleepWake();
+  delay(1);  // yield();
+  WiFi.persistent(false); // don't load and save credentials to flash
+  WiFi.mode(WIFI_STA);
+  if (esp_now_init()==0) {
+    if(esp_now_set_self_role(ESP_NOW_ROLE_CONTROLLER)==0){
+
+      esp_now_add_peer(remoteMac, ESP_NOW_ROLE_SLAVE, WIFI_CHANNEL, NULL, 0);
+      u8 bs[sizeof(sd)];
+      memcpy(bs, &sd, sizeof(sd));
+      esp_now_send(NULL, bs, sizeof(sd)); // max ESP_NOW_MAX_DATA_LEN
+
+    } else {
+      Serial.println("error configuring ESP NOW");
+    }
+  } else {
+    Serial.println("error initializing ESP NOW");
+  }
+  esp_now_deinit();
+  WiFi.mode(WIFI_OFF);
+  WiFi.forceSleepBegin();
+  delay(1); // yield();
+  Serial.printf("sendESPNOW() took %d ms\n", millis()-espnowmillis);
+}
+
 void ICACHE_RAM_ATTR ISR_geiger_impulse() {
   geiger_counts++;
 }
@@ -234,5 +280,10 @@ void setup() {
 
 void loop() {
   sendValues();
-  delay(postingInterval);
+  /* keep powerbank happy */
+  for(int i=0; i<(postingInterval/powerbankInterval)-1; i++) {
+    delay(powerbankInterval);
+    sendESPNOW();
+  }
+  delay(powerbankInterval);
 }