{"id":6862,"date":"2018-05-14T01:14:30","date_gmt":"2018-05-13T23:14:30","guid":{"rendered":"http:\/\/xylem.aegean.gr\/~modestos\/mo.blog\/?p=6862"},"modified":"2020-04-15T20:26:00","modified_gmt":"2020-04-15T18:26:00","slug":"esp32-send-dht-to-mqtt-and-deepsleep","status":"publish","type":"post","link":"https:\/\/xylem.aegean.gr\/~modestos\/mo.blog\/esp32-send-dht-to-mqtt-and-deepsleep\/","title":{"rendered":"Use an ESP32 board to send DHT to MQTT and then deep sleep"},"content":{"rendered":"

Here is an example of how I post humidity and temperature values that I collect from a DHT11 sensor. I use an ESP32 (Lolin32<\/a>) board and I post values to a MQTT open source message broker (Eclipse Mosquitto<\/a>) that I run alongside openhab on a Rpi3. Finally, I deep sleep the board to save energy.<\/p>\n

I use the following libraries: <\/p>\n

    \n
  1. Arduino library for DHT11\/DHT22 by Adafruit [>><\/a>]<\/li>\n
  2. Arduino Client for MQTT (PubSubClient) by Nick O’Leary [>><\/a>]<\/li>\n
  3. Arduino core for ESP32 WiFi chip [>><\/a>]<\/li>\n<\/ol>\n

    To install CP210x Driver v10.1.1 for Lolin32 ESP32 there installation issue with Windows 10, build 1803. Check this post: [>><\/a>]<\/p>\n

    \"\"<\/a> \"\"<\/a><\/p>\n

    \/* Project ESP32, DHT, MQTT and Deepsleep *\/\r\n#include <WiFi.h>\r\n#include <PubSubClient.h>\r\n#include \"DHT.h\"          \/\/ Library for DHT sensors\r\n\r\n#define wifi_ssid \"My_APs_ssid\"         \/\/wifi ssid\r\n#define wifi_password \"my_password\"     \/\/wifi password\r\n\r\n#define mqtt_server \"mqtt_broker_IP\"  \/\/ server name or IP\r\n#define mqtt_user \"username\"      \/\/ username\r\n#define mqtt_password \"password\"   \/\/ password\r\n\r\n#define temperature_topic \"topic\/temp1\"       \/\/Topic temperature\r\n#define humidity_topic \"topic\/humid1\"         \/\/Topic humidity\r\n#define debug_topic \"debug\"                   \/\/Topic for debugging\r\n\r\n\/* definitions for deepsleep *\/\r\n#define uS_TO_S_FACTOR 1000000        \/* Conversion factor for micro seconds to seconds *\/\r\n#define TIME_TO_SLEEP 900              \/* Time ESP32 will go to sleep for 15 minutes (in seconds) *\/\r\n#define TIME_TO_SLEEP_ERROR 3600       \/* Time to sleep in case of error (1 hour) *\/\r\n\r\nbool debug = true;             \/\/Display log message if True\r\n\r\n#define DHTPIN 14               \/\/ DHT Pin \r\n\/\/ Uncomment depending on your sensor type:\r\n#define DHTTYPE DHT11           \/\/ DHT 11 \r\n\/\/#define DHTTYPE DHT22         \/\/ DHT 22  (AM2302)\r\n\r\n\/\/ Create objects\r\nDHT dht(DHTPIN, DHTTYPE);     \r\nWiFiClient espClient;\r\nPubSubClient client(espClient);\r\n\r\nvoid setup() {\r\n  Serial.begin(115200);     \r\n  setup_wifi();                           \/\/Connect to Wifi network\r\n   \r\n  client.setServer(mqtt_server, 1883);    \/\/ Configure MQTT connection, change port if needed.\r\n\r\n  if (!client.connected()) {\r\n    reconnect();\r\n  }\r\n  dht.begin();\r\n  \r\n  \/\/ Read temperature in Celcius\r\n    float t = dht.readTemperature();\r\n  \/\/ Read humidity\r\n    float h = dht.readHumidity();\r\n  \r\n\r\n  \/\/ Nothing to send. Warn on MQTT debug_topic and then go to sleep for longer period.\r\n    if ( isnan(t) || isnan(h)) {\r\n      Serial.println(\"[ERROR] Please check the DHT sensor !\");\r\n      client.publish(debug_topic, \"[ERROR] Please check the DHT sensor !\", true);      \/\/ Publish humidity on broker\/humid1\r\n      esp_sleep_enable_timer_wakeup(TIME_TO_SLEEP * uS_TO_S_FACTOR); \/\/go to sleep\r\n      Serial.println(\"Setup ESP32 to sleep for every \" + String(TIME_TO_SLEEP) + \" Seconds\");\r\n      Serial.println(\"Going to sleep now because of ERROR\");\r\n      esp_deep_sleep_start();\r\n      return;\r\n    }\r\n  \r\n    if ( debug ) {\r\n      Serial.print(\"Temperature : \");\r\n      Serial.print(t);\r\n      Serial.print(\" | Humidity : \");\r\n      Serial.println(h);\r\n    } \r\n    \/\/ Publish values to MQTT topics\r\n    client.publish(temperature_topic, String(t).c_str(), true);   \/\/ Publish temperature on broker\/temp1\r\n    if ( debug ) {    \r\n      Serial.println(\"Temperature sent to MQTT.\");\r\n    }\r\n    delay(100); \/\/some delay is needed for the mqtt server to accept the message\r\n    client.publish(humidity_topic, String(h).c_str(), true);      \/\/ Publish humidity on broker\/humid1\r\n    if ( debug ) {\r\n    Serial.println(\"Humidity sent to MQTT.\");\r\n    }   \r\n\r\n  esp_sleep_enable_timer_wakeup(TIME_TO_SLEEP * uS_TO_S_FACTOR); \/\/go to sleep\r\n  Serial.println(\"Setup ESP32 to sleep for every \" + String(TIME_TO_SLEEP) + \" Seconds\");\r\n  Serial.println(\"Going to sleep as normal now.\");\r\n  esp_deep_sleep_start();\r\n}\r\n\r\n\/\/Setup connection to wifi\r\nvoid setup_wifi() {\r\n  delay(20);\r\n  Serial.println();\r\n  Serial.print(\"Connecting to \");\r\n  Serial.println(wifi_ssid);\r\n\r\n  WiFi.begin(wifi_ssid, wifi_password);\r\n\r\n  while (WiFi.status() != WL_CONNECTED) {\r\n    delay(100);\r\n    Serial.print(\".\");\r\n  }\r\n\r\n Serial.println(\"\");\r\n Serial.println(\"WiFi is OK \");\r\n Serial.print(\"=> ESP32 new IP address is: \");\r\n Serial.print(WiFi.localIP());\r\n Serial.println(\"\");\r\n}\r\n\r\n\/\/Reconnect to wifi if connection is lost\r\nvoid reconnect() {\r\n\r\n  while (!client.connected()) {\r\n    Serial.print(\"Connecting to MQTT broker ...\");\r\n    if (client.connect(\"ESP32Client\", mqtt_user, mqtt_password)) {\r\n      Serial.println(\"OK\");\r\n    } else {\r\n      Serial.print(\"[Error] Not connected: \");\r\n      Serial.print(client.state());\r\n      Serial.println(\"Wait 5 seconds before retry.\");\r\n      delay(5000);\r\n    }\r\n  }\r\n}\r\n\r\nvoid loop() { \r\n}<\/pre>\n
    I also used MQTTLens<\/a> plugin for Chrome in order to debug my MQTT broker.<\/p>\n
    \"\"<\/a><\/p>\n
    \n
     <\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"
    Here is an example of how I post humidity and temperature values that I collect from a DHT11 sensor. I use an ESP32 (Lolin32) board and I post values to a MQTT open source message broker (Eclipse Mosquitto) that I run alongside openhab on a Rpi3. Finally, I deep sleep the board to save energy. I use the following libraries:  Arduino library for DHT11\/DHT22 by Adafruit [>>] Arduino Client for MQTT (PubSubClient) by Nick O’Leary [>>] Arduino core for ESP32 WiFi chip [>>] To install CP210x Driver v10.1.1 for Lolin32 ESP32 there installation issue with Windows 10, build 1803. Check this post: [>>] \/* Project ESP32, DHT, MQTT and Deepsleep *\/ #include <WiFi.h> #include <PubSubClient.h> #include “DHT.h” \/\/ Library for DHT sensors #define wifi_ssid “My_APs_ssid” \/\/wifi ssid #define wifi_password “my_password” \/\/wifi password #define mqtt_server “mqtt_broker_IP” \/\/ server name or IP #define mqtt_user “username” \/\/ username #define mqtt_password “password” \/\/ password #define temperature_topic […]<\/p>\n","protected":false},"author":1,"featured_media":6872,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"inline_featured_image":false,"rop_custom_images_group":[],"rop_custom_messages_group":[],"rop_publish_now":"initial","rop_publish_now_accounts":[],"rop_publish_now_history":[],"rop_publish_now_status":"pending","ngg_post_thumbnail":0,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"jetpack_post_was_ever_published":false},"categories":[682,730,729],"tags":[781,780,774,777,779],"class_list":["post-6862","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-arduino","category-esp32","category-espressif","tag-deep-sleep","tag-dht","tag-esp32","tag-openhab","tag-openhab2"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\n\t\n\t\t