2011

Author: Manoj

Reviewer: Mithun

Revision: 1.1

Tenet Technetronics

7/15/2011

Application Note: AN101 Connecting Arduino to Thingspeak using python as an middle ware

i

Contents

Introduction

Introduction to Arduino connected to Thingspeak

Hardware Overview

Schematic

Software Overview

Flow Chart

Pseudo code

Code

Demo Application

References and further reading

1

Introduction

Here the Arduino is connected to Thingspeak through python and python is communicating to

Arduino through Pyserial. Pyserial supports two way communications with file handles. You

can read and write strait to serial. I am using it to read potentiometer data which is connected to

Arduino and uploading the same data to Thingspeak.

Hardware required

Arduino/Comet

Potentiometer (10k)

You can buy the products and other electronic components at

www.tenettech.com

Software required

Arduino IDE

Python Emac editor

You can download the Arduino software, Emac editor, python, and pyserial package through

the following links

www.arduino.cc

http://www.gnu.org/software/emacs/

http://python.org/download/

http://linux.softpedia.com/get/Programming/Libraries/pySerial-51222.shtml

2

Hardware Overview

Schematic

Here we are connecting variable potentiometer (1k) to Arduino analog pin A0.

Fig1: schematic

NOTE: The pin out for variable potentiometer

Fig2: potentiometer pin out

3

Software overview

Flowchart

For python: For Arduino:

NO

YES

Void setup

Serial communication

initialization

Void loop

Read analog values

from A0

Start

End

print the analog

values and update

the same data to

thingspeak

Serial

communication and

baud rate

initialization

Read the data from

the potentiometer

Start

End

While

true

If new

data

Print the previous

value

4

Pseudo code

For python:

Include header files for SERIAL and HTTP

Global declaration:

For Serial port selection

For setting baud rate.

For variable to store serial data.

Loop : While

Description : infinite loop

Body : reading analog values continuously

Condition : if

Description : if condition true control enters the body

Body : If there is newly available serial data then print the value and store

it in a new variable

Set up a connection

Condition : else

Description : if all the conditions fails control enters the body

Body : store the previously read value

For Arduino:

Function : setup

Return type : void

Description : initialization

Body : serial communication initialization

Function : loop

Return type : void

Description : infinite loop

Body : read analog values from Arduino analog pin A0

5

code

PYTHON CODE:

import httplib2 // for HTTP connection

import serial // for serial communication

ser = serial.Serial('/dev/ttyACM0') // serial port selected as /dev/ttyACM0 in arduino

ser.baudrate = 9600 // baud rate is set to 9600

temp = ''

a = 0

while True:

ch = ser.read(1)

if ch == '\n':

print temp

a = int(temp)

conn = httplib2.Http()

// include API KEY for your channel

conn.request("http://api.thingspeak.com/update?key=VQ927LPM9PNYMTQP&field1=%d"

%(a))

temp = ''

else:

temp += ch

ARDUINO CODE:

/* AnalogReadSerial

Reads an analog input on pin 0, prints the result to the serial monitor */

void setup() {

Serial.begin(9600); //baud rate is set to 9600

}

void loop() {

int sensorValue = analogRead(A0); // reading analog values from A0 of arduino

Serial.println(sensorValue); // printing the read values

}

6

Demo Application

Through this demo application we are going to read the analog values from the Potentiometer

and the same data we are uploading to the Thing speak using an Arduino and an internet

connection from the PC

Here i have connected a potentiometer to the Arduino

Fig3: Arduino with potentiometer

The Arduino sketch for reading the analog values from the potentiometer

Fig4: Arduino with potentiometer

7

Serial monitor showing the values which is read from potentiometer

Fig5: Arduino serial monitor

Python code on emac editor which tell to read and upload the same Data to Thingspeak

Fig6: python code

8

Open the terminal on the Linux operating system.

Fig7: Linux terminal

Here I have called python code, and we can see the data from the potentiometer on the terminal

is same as the Arduino serial monitor data.

Fig8: results on terminal window

9

Things speak home page, we need to log in with our account

Fig9: Thingspeak homepage

Here I have signed in and you can see the channels given to me.

Fig10: Thingspeak channel

10

Here is my channel 873 click for VIEW CARTS .

Fig11: Thingspeak charts screen

Through this link u can fill up the chart characteristics as per the need

http://community.thingspeak.com/documentation/api/#charts

Fig12: chart documentation screen

11

Here is my output on my cart which is same on terminal and serial monitor

Fig13: results on Thingspeak chart

References and Further Reading

www.arduino.cc

www.tenettech.com/comet

http://community.thingspeak.com/documentation/api/#charts

http://community.thingspeak.com

http://pyserial.sourceforge.net/

http://python.org/

12

Contact details

Tenet Technetronics,

No 8/14, Third Floor, MN Chambers,

P.T.Street,

Opp to Pai Vista Convention Hall,

Basavangudi,

Bangalore -560004, India

Ph: 080-42103124

Email : info@tenettech.com