The Daily Duino

Another post on Pachube and how easy it is to get setup and going. This post will cover the basic steps on how to get some sensors online!  I will be using my project of two light sensors as an example.  The status of my light sensors are viewable at http://www.pachube.com/feeds/2145

Pachube + Arduino from Morgellon on Vimeo.

STEP ONE: GET A PACHUBE ACCOUNT!

Head over to the Pachube website and see various sensors from all over the world and view their status.  Be sure to view the ABOUT page, this describes INPUTs and OUTPUTs, along with ways to interface with Pachube and your sensors.  The QUICKSTART page has the details to get started and how to use your API.  Pachube is still in beta, so you’ll need to get an invite code… but no worries, Pachube has an email address on the QUICKSTART page.  Just send them and email asking for an invite and what you would like to do.  If they let me in… they will let anyone in!

STEP TWO: PREPARE ARDUINO!

The Arduino can be interfaced with Pachube two ways: 1. With an Ethernet shield OR 2. Via USB connected to a PC running Processing… which is the way used in this tutorial… as I feel it is an easy and inexpensive way.  You can learn more about each way at the Pachube Arduino page.

To prep the Arduino, you need to connect the sensors you will be using and verify that they are working correctly! Once the sensors are good, then upload the “Standard Firmata” to the Arduino.  Now the Arduino is prepped for Pachube!  Leave the Arduino connected to the PC.

STEP THREE: PREPARE PROCESSING!

To have Processing communicate easily with Pachube, you will need to add a few libraries.  They are the Pachuino, Arduino and EEML libraries, they are available and there is more info at the PACHUINO page.  Download, unzip and move them to the libraries folder, in your sketchbook folder.  Now Processing is ready!

STEP FOUR: PREPARE INPUT FEED!

Once you have a Pachube account and your API key, go ahead and set up a new feed for your sensors.  Since I have light sensors, I started a new INPUT FEED.  I chose to make my feed “manual” (as this is easier for me) which means Pachube gets updates only when I send them.  Instead of Pachube connecting directly to my PC to pull the info.

STEP FIVE: PREPARE CODE FOR PROCESSING!

Once you have the libraries in the folder, you are ready to start Processing and start coding.  Below is the code I used for my light sensor.  This was taken from the sample code and stripped to make it more simple. I added a LED on pin 11 to light up (to let me know when my Arduino was running) and a delay(1500).

Be sure to add you API Key, and the URL of your INPUT FEED!

import processing.serial.*;
import cc.arduino.*;
import eeml.*;
import pachuino.*;

Pachuino p;
Arduino arduino;
int ledPin = 11;

void setup(){
p = new Pachuino(this, Arduino.list()[0], 115200);
p.manualUpdate(”http://www.pachube.com/api/2145.xml”); // change URL — this is the feed you want to update
p.setKey(”—YOUR API KEY HERE—”);

// local sensors
p.addLocalSensor(”analog”, 0,”Light Sensor Inside”);
p.addLocalSensor(”analog”, 1,”Light Sensor Outside”);
}

void draw(){
//p.debug();
p.digitalWrite(ledPin, Arduino.HIGH);
delay(1500);
}

// you don’t need to change any of these

void onReceiveEEML(DataIn d){
p.updateRemoteSensors(d);
}

STEP SIX: LAUNCH CODE AND COLLECT DATA!

Make sure that:

• Sensors are *working* and connected to Arduino
• Arduino is running “Standard Firmata” and connected to computer
• Processing is collecting sensor data from Arduino
• Computer has Internet connection

Now run your program and begin collecting data and sharing it on the web!!  Check your feed to make sure you data is being transmitted.  Have fun and happy tinkering!

–Morgellon OUT!

Quick update before I zonk out…  Yesterday I setup an account for Pachube and spent all night getting familiar with how it works. Pachube describes itself as a service that enables you to connect, tag and share real time sensor data from objects, devices, buildings and environments around the world. The key aim is to facilitate interaction between remote environments, both physical and virtual.

It also works with Arduino and Processing… hrmmmmm…..

The graphs will continue to update as they receive more data from the sensors.  It will be interesting to watch and compare the differences in the two graphs.  More to come soon!

–Morgellon OUT!!

After watching Citizen Engineer, I wanted to play with a slotted optical sensor, well that and a payphone, a sim card reader, a little vice and other cool electronics things. So I ordered a few from All Electronics.

As usual, I had no idea how these things work, so I started plugging in wires and using a standard analog input sketch. That did not work at all, after I heard something pop I knew I was not on the right track. Then I started looking for some help. I still have not found a datasheet, but I found a graphic that made things work for me. My exact model is the OPB3902.

There are four pins on the bottom of these things, two to work the emitter (E) (pins 1 and 3) and two for the detector (D) (pins 2 and 4). Two resistors are needed, a 330 Ohm (orange orange red) and 2.2 K (red red orange).

I mounted the Optical Sensor on a proto board, having carefully cut off the plastic bump on the bottom of the sensor. I also used a led with a 1K (brown black red) for signaling when something was activating the switch. According to the drawing 5 volts would work, so that’s what I used, along with analog pin 2 for input and digital pin 12 for the signaling led.

After running my sketch and dumping the sensor reading to serial I found that it idled at ~929 and when the sensor was activated it was ~1020.  This is great, no problem to see a change of state, so I wrote a bit more code to activate the led.  I did not include a delay as I wanted the led to react quickly.

Here is my code, feel free to do with it as you will!

/*
Demo for a slotted optical sensor.

I am sure that someone elses code is in here somewhere
*/

int inputPin = 2;    // select the input pin for the potentiometer
int ledPin = 12;   // select the pin for the LED
int val = 0;       // variable to store the value coming from the sensor

void setup() {
  pinMode(inputPin, OUTPUT);  // declare the ledPin as an OUTPUT
  pinMode(ledPin, OUTPUT);
  Serial.begin(9600);
}

void loop() {

  val = analogRead(inputPin);    // read the value from the sensor
  Serial.println(val);

  if(val > 950){
    digitalWrite(ledPin, HIGH);  // turn the ledPin on
  } else {
    digitalWrite(ledPin, LOW);   // turn the ledPin off
  }
}

I am very excited to know how to set up this sensor.  Next time I am going to find some with the hook up wires already soldered and heatshrinked on.  For those that are curious, that is a Freeduino from NKC under there.