MQ Telemetry Transport client publishing parameters measured by a DHT11 sensor. Ethernet connection is via an ENC28J60 module.
Dependencies: DHT11 MQTTClient UIPEthernet mbed
Diff: main.cpp
- Revision:
- 0:092b5e724233
- Child:
- 1:4be688be4e0d
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/main.cpp Mon Sep 15 17:08:18 2014 +0000 @@ -0,0 +1,110 @@ +// In this example an MQTT client is created. +// It is publishing parameters measured by a DHT11 sensor +// UIPEthernet library is used to drive the ENC28J60 board +#include <mbed.h> +#include <UIPEthernet.h> +#include <UIPClient.h> +#include <MQTTClient.h> +#include <DHT11.h> + +// UIPEthernet is the name of a global instance of UIPEthernetClass. +// Do not change the name! It is used within the UIPEthernet library. +// Adapt the SPI pin names to your mbed platform/board if not present yet. +#if defined(TARGET_LPC1768) +UIPEthernetClass UIPEthernet(p11, p12, p13, p8); // mosi, miso, sck, cs +DHT11 dht11(p6); +#elif defined (TARGET_NUCLEO_F103RB) +UIPEthernetClass UIPEthernet(PB_5, PB_4, PB_3, PB_6); // mosi, miso, sck, cs +DHT11 dht11(PC_14); +#endif + +// Make sure that the MAC number is unique within the connected network. +const uint8_t MY_MAC[6] = {0x00,0x01,0x02,0x03,0x04,0x05}; +// IP address must be unique and compatible with your network too. Change as appropriate. +const IPAddress MY_IP(192,168,1,181); +char message_buff[100]; +void onMessage(char* topic, uint8_t* payload, unsigned int length); +IPAddress serverIP(192,168,1,30); // MQTT server (e.g. 'mosquitto' running on a Raspberry Pi or Ubuntu) +EthernetClient ethernetClient; +void onMqttMessage(char* topic, uint8_t* payload, unsigned int length); +MQTTClient mqttClient(serverIP, 1883, onMqttMessage, ethernetClient); +const int PERIOD = 10; // seconds + +Serial pc(USBTX, USBRX); + +int main() +{ + const int MAX_COUNT = 5; + int i = 0; + bool connected = false; + time_t t = 0; + time_t lastTime = 0; + + // initialize the ethernet device + Ethernet.begin(MY_MAC, MY_IP); + pc.printf("Connecting to MQTT server ..\r\n"); + do { + wait(1.0); + connected = mqttClient.connect("myMqttClient"); + } while(!connected && (i < MAX_COUNT)); + + if(connected) { + pc.printf("MQTT Server connected.\r\n"); + mqttClient.subscribe("rt_clock"); + pc.printf("Subscribed to: "); + pc.printf("rt_clock\r\n"); + } else { + pc.printf("Failed to connect to MQTT server.\r\n"); + } + + while(1) { + t = time(NULL); + if(t >= (lastTime + PERIOD)) { + lastTime = t; + if(connected) { + sprintf(message_buff, "%ds:\r\n", t); + pc.printf("---------------------\r\n"); + pc.printf(message_buff); + int state = dht11.readData(); + if(state == DHT11::OK) { + float hum = dht11.readHumidity(); + sprintf(message_buff, "%4.1f", hum); + pc.printf(" hum = %s%%\r\n", message_buff); + mqttClient.publish("outdoor/humidity", message_buff); + float temp = dht11.readTemperature(); + sprintf(message_buff, "%5.1f", temp); + pc.printf(" temp = %s'C\r\n", message_buff); + mqttClient.publish("outdoor/temperature", message_buff); + float dewPoint = temp - (100 - hum)/5.0; + sprintf(message_buff, "%5.1f", dewPoint); + pc.printf(" dew point = %s'C\r\n", message_buff); + mqttClient.publish("outdoor/dewpoint", message_buff); + } + else + pc.printf(" DHT11 error: %d\r\n", state); + } + } + mqttClient.loop(); // MQTT client loop processing + } +} + +void onMqttMessage(char* topic, uint8_t* payload, unsigned int length) +{ + int i = 0; + + pc.printf("Message arrived:\r\n"); + pc.printf(" Topic: %s\r\n", topic); + pc.printf(" Length: %d\r\n", length); + + // create character buffer with ending null terminator (string) + for(i = 0; i < length; i++) { + message_buff[i] = payload[i]; + } + + message_buff[i] = '\0'; + pc.printf(" Payload: %s\r\n", message_buff); +} + + + +