MQTT: Arduino Simple Read Write - Revision history

Onnowpurbo at 23:56, 10 May 2017

2017-05-10T23:56:04Z

@@ Line 1: / Line 1: @@
 sumber: http://m2mio.tumblr.com/post/30048662088/a-simple-example-arduino-mqtt-m2mio
-I hope you find it useful.
+==Connect.  Send.  Store.  Use.==
   Connect:  The Arduino will connect via MQTT to the m2m broker.
@@ Line 15: / Line 8: @@
   Store:  If formatted correctly, any MQTT traffic going to the broker will be stored for retrieval in the future.
   Use:  The platform provides a simple, RESTful API for client applications to make use of their stored data.
 ==Arduino - Hardware==
@@ Line 28: / Line 19: @@
 * LED
 * Wires
 ==Arduino - Software / MQTT==
-There are four main tasks the Arduino software needs to take care of for this example:
+Empat (4) tugas Arduino
 * Gather light sensor readings periodically
@@ Line 77: / Line 65: @@
   PubSubClient client(server, 1883, callback, ethClient);
-  // Pin 9 is the LED output pin
+  // Pin 13 is the LED output pin
   int ledPin = 13;
-  // Analog 0 is the input pin
+  // Analog 2 is the input pin
-  int lightPinIn = 0;
+  int lightPinIn = 2;
   // defines and variable for sensor/control mode
@@ Line 113: / Line 101: @@
         // clientID, username, MD5 encoded password
         // arduino-mqtt, mqtt-spt, e10adc3949ba59abbe56e057f20f883e (123456)
-        client.connect("arduino-mqtt", "mqtt-spy", "e10adc3949ba59abbe56e057f20f883e");
+       // arduino-mqtt (bisa tanpa username & password, sebagai anonymous)
         client.publish("arduino/lightsensor", "I'm alive!");
         client.subscribe("arduino/lightsensor");
@@ Line 187: / Line 176: @@

Onnowpurbo at 21:47, 10 May 2017

2017-05-10T21:47:23Z

← Older revision		Revision as of 21:47, 10 May 2017
Line 54:		Line 54:

	Below is the Arduino code. Note: This requires both the Ethernet library and MQTT Client Library to be installed in your Arduino library folder. See an example here on how to install Arduino libraries. (it’s easy!)		Below is the Arduino code. Note: This requires both the Ethernet library and MQTT Client Library to be installed in your Arduino library folder. See an example here on how to install Arduino libraries. (it’s easy!)



	#include <SPI.h>		#include <SPI.h>
Line 69:		Line 71:
	// MAC Address of Arduino Ethernet Sheild (on sticker on shield)		// MAC Address of Arduino Ethernet Sheild (on sticker on shield)
	byte MAC_ADDRESS[] = { 0x90, 0xA2, 0xDA, 0x0D, 0x31, 0xB8 };		byte MAC_ADDRESS[] = { 0x90, 0xA2, 0xDA, 0x0D, 0x31, 0xB8 };
	PubSubClient client;		IPAddress ip(192, 168, 0, 4);
			IPAddress server(192, 168, 0, 100);

			EthernetClient ethClient;
			PubSubClient client(server, 1883, callback, ethClient);

	// Pin 9 is the LED output pin		// Pin 9 is the LED output pin
Line 99:		Line 105:
	return;		return;
	}		}

	~~client = PubSubClient(MQTT_SERVER, 1883, callback);~~
	}		}

Line 127:		Line 131:

	// read from light sensor (photocell)		// read from light sensor (photocell)
	int lightRead = analogRead(lightPinIn);		int lightRead = analogRead(lightPinIn);

	// if there is light in the room, turn off LED		// if there is light in the room, turn off LED
Line 153:		Line 157:
	// MQTT client loop processing		// MQTT client loop processing
	client.loop();		client.loop();
	}		}

	// handles message arrived on subscribed topic(s)		// handles message arrived on subscribed topic(s)
	void callback(char* topic, byte* payload, unsigned int length) {		void callback(char* topic, byte* payload, unsigned int length) {

	int i = 0;		int i = 0;

	//Serial.println("Message arrived: topic: " + String(topic));		//Serial.println("Message arrived: topic: " + String(topic));
Line 181:		Line 185:
	}		}
	}		}





	==mqtt.io MQTT Client - Publish / Subscribe==		==mqtt.io MQTT Client - Publish / Subscribe==

Onnowpurbo at 21:23, 10 May 2017

2017-05-10T21:23:58Z

← Older revision		Revision as of 21:23, 10 May 2017
Line 11:		Line 11:
	This example was crafted to illustrate the main concepts of the m2m.io platform.		This example was crafted to illustrate the main concepts of the m2m.io platform.

	Connect: The Arduino will connect via MQTT to the m2m broker.		Connect: The Arduino will connect via MQTT to the m2m broker.
			Send: Sensor data is sent to the broker/platform and command data is sent to the Arduino.
	Send: Sensor data is sent to the broker/platform and command data is sent to the Arduino.		Store: If formatted correctly, any MQTT traffic going to the broker will be stored for retrieval in the future.
			Use: The platform provides a simple, RESTful API for client applications to make use of their stored data.
	Store: If formatted correctly, any MQTT traffic going to the broker will be stored for retrieval in the future.

	Use: The platform provides a simple, RESTful API for client applications to make use of their stored data.

	This simple sensor application gathers light sensor data which is published to the broker. Commands can be sent via MQTT to the sensor.		This simple sensor application gathers light sensor data which is published to the broker. Commands can be sent via MQTT to the sensor.

	==Arduino - Hardware==		==Arduino - Hardware==

	The circuits I constructed allow the Arduino device to read light levels using an analog input and (optionally) control an LED based on a set light level. The optional LED portion of the circuit makes the Arduino a very simple control system which controls an output based on input values it senses.

	I started with the SparkFun Arduino Inventor’s Kit which includes the components necessary to create a light sensing circuit. This could easily be done with any Arduino device capable of hosting the Arduino Ethernet Shield and a couple standard components.

	Parts List		Parts List

Onnowpurbo at 21:38, 8 May 2017

2017-05-08T21:38:10Z

← Older revision		Revision as of 21:38, 8 May 2017
Line 72:		Line 72:
	*/		*/

	#define MQTT_SERVER "q.~~m2m~~.io"		#define MQTT_SERVER "192.168.0.100"

	// MAC Address of Arduino Ethernet Sheild (on sticker on shield)		// MAC Address of Arduino Ethernet Sheild (on sticker on shield)
Line 79:		Line 79:

	// Pin 9 is the LED output pin		// Pin 9 is the LED output pin
	int ledPin = 9;		int ledPin = 13;
	// Analog 0 is the input pin		// Analog 0 is the input pin
	int lightPinIn = 0;		int lightPinIn = 0;
Line 115:		Line 115:
	{		{
	// clientID, username, MD5 encoded password		// clientID, username, MD5 encoded password
	client.connect("arduino-mqtt", "~~john@m2m.io~~", "~~00000000000000000000000000000~~");		// arduino-mqtt, mqtt-spt, e10adc3949ba59abbe56e057f20f883e (123456)
	client.publish("~~io.m2m/~~arduino/lightsensor", "I'm alive!");		client.connect("arduino-mqtt", "mqtt-spy", "e10adc3949ba59abbe56e057f20f883e");
	client.subscribe("~~io.m2m/~~arduino/lightsensor");		client.publish("arduino/lightsensor", "I'm alive!");
			client.subscribe("arduino/lightsensor");
	}		}

Line 151:		Line 152:
	pubString.toCharArray(message_buff, pubString.length()+1);		pubString.toCharArray(message_buff, pubString.length()+1);
	//Serial.println(pubString);		//Serial.println(pubString);
	client.publish("~~io.m2m/~~arduino/lightsensor", message_buff);		client.publish("arduino/lightsensor", message_buff);
	}		}

Onnowpurbo: Undo revision 47817 by Onnowpurbo (talk)

2017-05-08T08:27:34Z

Undo revision 47817 by Onnowpurbo (talk)

Show changes

Onnowpurbo at 08:26, 8 May 2017

2017-05-08T08:26:59Z

Show changes

Onnowpurbo at 08:20, 8 May 2017

2017-05-08T08:20:59Z

Show changes

Onnowpurbo: Created page with "sumber: http://m2mio.tumblr.com/post/30048662088/a-simple-example-arduino-mqtt-m2mio This post shows a quick example of using MQTT and the m2m.io platform with an Arduino dev..."

2017-05-08T08:15:42Z

Created page with "sumber: http://m2mio.tumblr.com/post/30048662088/a-simple-example-arduino-mqtt-m2mio This post shows a quick example of using MQTT and the m2m.io platform with an Arduino dev..."

New page

sumber: http://m2mio.tumblr.com/post/30048662088/a-simple-example-arduino-mqtt-m2mio

This post shows a quick example of using MQTT and the m2m.io platform with an Arduino device. I walk through the platform from end to end starting with setting up the Arduino to capture sensor data and ending with a super simple Play! app which shows the past sensor readings by consuming the data presented by the m2m.io platform API.

I hope you find it useful.

Overview

Connect. Send. Store. Use.

This example was crafted to illustrate the main concepts of the m2m.io platform.

Connect: The Arduino will connect via MQTT to the m2m broker.

Send: Sensor data is sent to the broker/platform and command data is sent to the Arduino.

Store: If formatted correctly, any MQTT traffic going to the broker will be stored for retrieval in the future.

Use: The platform provides a simple, RESTful API for client applications to make use of their stored data.

This simple sensor application gathers light sensor data which is published to the broker. Commands can be sent via MQTT to the sensor.

Arduino - Hardware

The circuits I constructed allow the Arduino device to read light levels using an analog input and (optionally) control an LED based on a set light level. The optional LED portion of the circuit makes the Arduino a very simple control system which controls an output based on input values it senses.

I started with the SparkFun Arduino Inventor’s Kit which includes the components necessary to create a light sensing circuit. This could easily be done with any Arduino device capable of hosting the Arduino Ethernet Shield and a couple standard components.

Parts List

Arduino Device (in this example an Uno)
Arduino Ethernet Shield
Photocell
Resistors (10k, 330 ohm)
LED
Wires

Wiring Diagram
Photo of Completed Circuit

Arduino - Software / MQTT

There are four main tasks the Arduino software needs to take care of for this example:

Gather light sensor readings periodically
Publish sensor readings via MQTT
Listen for commands via MQTT
Control the LED based on a setpoint

An MQTT client is created in the setup function.

Every loop, the following happens:

The MQTT client connects (if it is not already connected).
Based on the “sensing mode” the application decides how to drive the LED. It could be OFF, ON or SENSE. In the SENSE case a light reading is taken and the LED is driven according to a hardcoded setpoint.
In the SENSE case, if 5 seconds have elapsed since the last reading a new reading is published via MQTT.

When connecting an MQTT client a callback function is specified to handle any incoming MQTT messages on the subscribed topic(s). In this function we check for commands in the proper JSON format and adjust our mode if the command specifies a new mode.

An interesting update to this app would be to handle receiving commands to change hardcoded values such as time we wait between publishing light readings or the “light”/“dark” setpoint.

Below is the Arduino code. Note: This requires both the Ethernet library and MQTT Client Library to be installed in your Arduino library folder. See an example here on how to install Arduino libraries. (it’s easy!)

#include <SPI.h>
#include <PubSubClient.h>
#include <Ethernet.h>

/*
* LightSensorMqttDemo
*
* A simple m2m.io platform demo for Arduino.
*/

#define MQTT_SERVER "q.m2m.io"

// MAC Address of Arduino Ethernet Sheild (on sticker on shield)
byte MAC_ADDRESS[] = { 0x90, 0xA2, 0xDA, 0x0D, 0x31, 0xB8 };
PubSubClient client;

// Pin 9 is the LED output pin
int ledPin = 9;
// Analog 0 is the input pin
int lightPinIn = 0;

// defines and variable for sensor/control mode
#define MODE_OFF 0 // not sensing light, LED off
#define MODE_ON 1 // not sensing light, LED on
#define MODE_SENSE 2 // sensing light, LED controlled by software
int senseMode = 0;

unsigned long time;

char message_buff[100];

void setup()
{
// initialize the digital pin as an output.
pinMode(ledPin, OUTPUT);

// init serial link for debugging
Serial.begin(9600);

if (Ethernet.begin(MAC_ADDRESS) == 0)
{
Serial.println("Failed to configure Ethernet using DHCP");
return;
}

client = PubSubClient(MQTT_SERVER, 1883, callback);
}

void loop()
{
if (!client.connected())
{
// clientID, username, MD5 encoded password
client.connect("arduino-mqtt", "john@m2m.io", "00000000000000000000000000000");
client.publish("io.m2m/arduino/lightsensor", "I'm alive!");
client.subscribe("io.m2m/arduino/lightsensor");
}

switch (senseMode) {
case MODE_OFF:
// light should be off
digitalWrite(ledPin, LOW);
break;
case MODE_ON:
// light should be on
digitalWrite(ledPin, HIGH);
break;
case MODE_SENSE:
// light is adaptive to light sensor

// read from light sensor (photocell)
int lightRead = analogRead(lightPinIn);

// if there is light in the room, turn off LED
// else, if it is "dark", turn it on
// scale of light in this circit is roughly 0 - 900
// 500 is a "magic number" for "dark"
if (lightRead > 500) {
digitalWrite(ledPin, LOW);
} else {
digitalWrite(ledPin, HIGH);
}

// publish light reading every 5 seconds
if (millis() > (time + 5000)) {
time = millis();
String pubString = "{\"report\":{\"light\": \"" + String(lightRead) + "\"}}";
pubString.toCharArray(message_buff, pubString.length()+1);
//Serial.println(pubString);
client.publish("io.m2m/arduino/lightsensor", message_buff);
}

}

// MQTT client loop processing
client.loop();
}

// handles message arrived on subscribed topic(s)
void callback(char* topic, byte* payload, unsigned int length) {

int i = 0;

//Serial.println("Message arrived: topic: " + String(topic));
//Serial.println("Length: " + String(length,DEC));

// create character buffer with ending null terminator (string)
for(i=0; i<length; i++) {
message_buff[i] = payload[i];
}
message_buff[i] = '\0';

String msgString = String(message_buff);

//Serial.println("Payload: " + msgString);

if (msgString.equals("{\"command\":{\"lightmode\": \"OFF\"}}")) {
senseMode = MODE_OFF;
} else if (msgString.equals("{\"command\":{\"lightmode\": \"ON\"}}")) {
senseMode = MODE_ON;
} else if (msgString.equals("{\"command\":{\"lightmode\": \"SENSE\"}}")) {
senseMode = MODE_SENSE;
}
}

mqtt.io MQTT Client - Publish / Subscribe

To communicate with our Arduino we’ll use the websocket MQTT client at mqtt.io.

Some quick notes, the username and password are entered in the Options tab before connecting. Signing in is required to see messages published on private namespaces. See the help article here for more information. The address we’ll use is the m2m MQTT broker at q.m2m.io, port 1883.

The screenshot below shows the Arduino publishing the “I’m Alive” message upon connecting. Note that this message wasn’t sent in JSON format so it won’t be stored by the platform.

Commands can be sent to the Arduino by publishing from the web client. Notice I publish commands in JSON format. This causes the commands to be stored by the platform and we’ll be able to see their history if we want to pull them up. Below is a screen shot showing publishing commands. The commands are seen in the subscribe window as they are sent.

In the sequence sent above, the Arduino turned on the LED when receiving the “ON” command and off when receiving the “OFF” command. Upon receiving the “SENSE” command it controlled the LED based on whether the light sensor was in the light or dark. This I was able to control by placing my hand over the photocell.

The screenshot below was captured while the Arduino was in SENSE mode. It continously publishes light readings every 5 seconds and this data is seen live on the MQTT topic.

Platform API - Consuming Past Data with Play! Application

Now that we have brought up the device, sent it some commands and saw it publish some sensor readings let’s use the m2m.io API to see what just happened. The API is documented in detail here.

For this example I wrote a quick Play! app in Scala. The code below shows the LightReading model. When the all() method is invoked, a call is generated to the past API endpoint requesting our “report:light” whatevers. (“whatevers” = whatever you want to send)

package models

import play.api.libs.ws.WS
import play.api.libs.json.JsObject
import com.ning.http.client.Realm
import com.codahale.jerkson.Json

case class LightReading(timestamp: Long, value: Int)

object LightReading {

def all(): List[LightReading] = {

var returnList: List[LightReading] = List()

val username = "john@m2m.io"
val password = "password"

val url = "http://api.m2m.io/1/past/io.m2m/arduino/lightsensor?whatevers=report:light"

val response = WS.url(url)
.withAuth(username, password, Realm.AuthScheme.BASIC)
.get().await(10000).get

var retJson = response.json.as[JsObject]

retJson.fields.map { j =>
val jsobj = j._2.as[JsObject]
val m = Json.parse[Map[String, Int]](jsobj.toString)
returnList = returnList :+ new LightReading(j._1.toLong, m.getOrElse("report:light", 0))
}

returnList
}
}

After deploying the application and requesting the past page, the app returns history for both values read and commands sent. There is a separate Command model similar to the one above to request “command:lightmode” whatevers.

Conclusion

Admittedly, this example is very simple. But I believe it is a good illustration of how I went from bare Arduino breadboard to retrieving sensor values from a cloud-hosted API in less than a day. Good luck with your projects!

==Referensi==

* http://m2mio.tumblr.com/post/30048662088/a-simple-example-arduino-mqtt-m2mio