DHT22.h:

#ifndef DHT22_H
#define DHT22_H

enum DHT22_Err_t {
  DHT22_ERR_NONE = 0,
  DHT22_ERR_HUNG = 1,
  DHT22_ERR_SYNC = 2,
  DHT22_ERR_CHKSUM = 3,
};

DHT22_Err_t getDHT22(int pin, float *temperature, float *humidity);

#endif

DHT22.ino:

#include "DHT22.h"

static byte _read_dht22_dat(volatile uint8_t *in, uint8_t bitmask)
{
  byte i = 0;
  byte result=0;
  for(i=0; i< 8; i++){
    while(!(*in & bitmask));  // wait for 50us
    delayMicroseconds(30);
 
    if(*in & bitmask) 
      result |=(1<<(7-i));
    while((*in & bitmask));  // wait '1' finish
  }
  return result;
}

DHT22_Err_t getDHT22(int pin, float *temperature, float *humidity)
{
  byte dht22_dat[5];
  byte dht22_in;
  byte i;

  uint8_t bitmask = digitalPinToBitMask(pin);
  volatile uint8_t port = digitalPinToPort(pin);
  volatile uint8_t *reg, *out, *in;

  // setup registers and pins
  reg = portModeRegister(port);
  out = portOutputRegister(port);
  in =  portInputRegister(port);
  *reg |= bitmask;
  *out |= bitmask;

  // start condition
  // 1. pull-down i/o pin from 18ms
  *out &= ~bitmask;
  delay(18);
  *out |= bitmask;
  delayMicroseconds(40);
 
  *reg &= ~bitmask;
  delayMicroseconds(40);
 
  dht22_in = *in & bitmask;
 
  if(dht22_in){
    Serial.println("dht22 start condition 1 not met");
    return DHT22_ERR_HUNG;
  }
  delayMicroseconds(80);
 
  dht22_in = *in & bitmask;
 
  if(!dht22_in){
    return DHT22_ERR_SYNC;
  }
  delayMicroseconds(80);
  // now ready for data reception
  for (i=0; i<5; i++)
    dht22_dat[i] = _read_dht22_dat(in, bitmask);
 
  *reg |= bitmask;
  *out |= bitmask;
 
  byte dht22_check_sum = dht22_dat[0]+dht22_dat[1]+dht22_dat[2]+dht22_dat[3];
  // check check_sum
  if(dht22_dat[4]!= dht22_check_sum)
  {
    return DHT22_ERR_CHKSUM;
  }
  
  *humidity=((float)(dht22_dat[0]*256+dht22_dat[1]))/10;
  *temperature=((float)(dht22_dat[2]*256+dht22_dat[3]))/10;
 
  return DHT22_ERR_NONE; 
}

This can be used as in in the following example:

#include "DHT22.h"

void setup() {
  Serial.begin(9600);
  delay(2000); // Recommended delay before sensor can be used
}

void loop() {
  DHT22_Err_t result;
  float temperature = 0, humidity = 0;
  
  result = getDHT22(4, &temperature, &humidity);  
  if (result != DHT22_ERR_NONE)
  {
    delay(5000);
    return;
  }
  
  Serial.print("Current humdity = ");
  Serial.print(humidity,1);
  Serial.print("%  ");
  Serial.print("temperature = ");
  Serial.print(temperature,1);
  Serial.println("C  ");
  delay(5000);
}

You may download the file ICTP_DHT22_XIG.zip. It contains a slightly enhanced example which transmits the information to the XBee Internet Gateway.

What is an XBee Pulse I/O?

A Fully Populated XBee Pulse I/O Board

The XBee Pulse I/O is a simple, general purpose electronic design which can be used for many automation and monitoring tasks. It includes up to two relays which may be driven through a one-shot pulse generator, simulating pressing and releasing a button, or it may be connected and controlled directly by the XBee’s digital output pins. There are also two powered digital inputs which can be used with closure sensors or leak detectors. It’s open-source hardware: use our design, improve it, sell it to your friends, or give it as a gift to win over your enemies.

The project is a collaboration between myself and my friend Andy Warner.

The XBee Pulse I/O is open-source hardware.

Introduction

The XBee Garage Door is an automation project which allows you to connect your automatic garage door lift to your mobile telephone via an Android or a mobile web application. This project was featured in Make Magazine Vol. 30 in the article "12,000-mile .

The XBee Garage Door project uses a Digi XBee to communicate and attaches to the door using a hardware design called the XBee Pulse I/O—a general purpose, open-source hardware design for simple automation projects.

There are four components to making your own XBee Garage Door:

1. An Breadboarded or populated printed circuit board (PCB) XBee Pulse I/O
2. A door-closure sensor and length of wire to connect to your existing automatic garage door lift button
3. A ConnectPort X gateway running the XIG application or a computer running the XIG with an XBee module attached
4. Using the Android or Web application to monitor and control your door remotely

Art Shanty Projects is a four-week exhibition that is part sculpture park, part artist residency and part social experiment, inspired by traditional ice fishing houses that dot the state's lakes in winter. It is an artist driven temporary community exploring the ways in which the relatively unregulated public space of the frozen lake can be used as a new and challenging artistic environment to expand notions of what art can be.

The DanceShanty, an innocuous white structure on a frozen lake, draws you inside with music and the sound of people having fun. As you enter you are invited to hangup your coat and dance!

My part in the DanceShanty was to design the lighting system for the project. Hans Scharler of ioBridge/ThingSpeak had shared the Cheerlights project with me where people have interconnected strands of GE Color Effects LED lights using ThingSpeak and a variety of communications components including Digi ConnectPort X2 Internet-to-ZigBee gateways and of course, good ol' Digi XBee radios.

I love lights. A hackable strand of full-color RGB Christmas lights are a dream come true. I found a strand of 25 lights for $25 at Sears. A little Processing and Arduino code (using my friend Rob Faludi's excellent book, of course!) and I had a prototype working in an evening. Using an SparkFun XBee Shield and a pair of Series 1 XBee Radios I was able to made the whole setup wireless—and able to hide away the PC from view while being able to maintain a connection to the lights. I work for Digi, so every design screams like it needs to be made wireless.

I am going to do a full tech write-up with source-code soon. The laptop I have in the DanceShanty now is old and slow and only able to run the display at about 10 frames per second. The Arduino code I wrote is able to run four synchronized strands of lights at well over 30 frames per second as you can see from the below staging video:

Before the DanceShanty comes down I am going to write a quick mobile app and connect the setup to people via iDigi in order to allow people dancing to choose the color and visualization mode of the lights. It's going to be sweet!

I took advantage of the holiday break to do some digital re-organization. I've retired my tired & faithful Gentoo Linux server and pushed everything up to "the cloud"&emdash;a virtual hosted server within Rackspace.

I'm no stranger to the cloud. I'm Product Manager at Digi International for the iDigi Device Cloud allowing ubiquitous access to any device to any application, anywhere. My home thermostat, gas and water meters are connected to my iPhone for monitoring and control via Digi International's Energy Daytrader application--incidentally, Energy Daytrader won Postscapes People's Choice aware for Best Internet of Things Self Tracking Application of 2011.

None of us are strangers to the cloud: so many of us use web-based e-mail applications such as GMail, social networking sites such as LinkedIn, and storage services such as Dropbox. We even use less obvious clouds like Flickr, Netflix and Hulu. In a sense even common infrastructure such as the mobile phone networks from AT&T, Verizon, T-Mobile and Sprint can be seen as clouds if one takes the term "cloud" to mean massively scalable, multi-tenant and secure products distributed as a service. I just hate the term cloud, it's opaque and literally nebulous.

Nonetheless the cloud is great. I migrated my Linux box up to Rackspace's cloud storage in hours using Duplicity and then executed a few commands to migrate my databases and get my webserver running. My site is faster, I can easily scale the performance and it's fully backed up. I'm so happy!

Hosting my machine at Rackspace will cost me about $263 per year or $21.90 per month. The electricity alone on my old server cost me about $60 per year or about $5.00 per month. Taking electricity into account, my overall cost of switching to the cloud is around $17 per month which I deem to be a fair price for the additional performance and services I receive.

I've got some big plans for 2012. Watch this space!

Image Source: Library of Congress

As Paros is an island, you've got to take a boat. I didn't immediately realize the significance of this until I was on board the ferry and motoring away from the hazy landmass of Athens. Out in the middle of the Aegean--long, long before the sea appeared to me as brushstroke washes of ultramarine blue and viridian green--I felt as though I was not only traveling but emigrating.

Surely I knew what I had signed up for: I wasn't leaving an impoverished, famine stricken land carrying all my portable property for a chance at a better life on Paros. I was vacationing from New York City to learn how to paint. Yet, there was a palpably different feeling to this trip.

Our incredible professor (and my friend of some years from Minnesota), Jun-Pierre Shiozawa, collected us individually from the ferry port as we arrived. We were taken to our quarters, a small set of apartments only 200 paces from the sea. I was shown the café in town were we would receive our free student meals. I was shown where to shop for our own groceries. I was shown where to walk to reach the classroom. I was even taught the particularities of the Greek toilet. These basic instructions heightened my sense of emigration. I wouldn't only be taught how to paint, I would be shown how to live.

During our first classroom session we had received an outline detailing our expected arrival time for each day, the topic to be covered during the day's class, and the start time and subject of the evening lecture. Still, many details were omitted--would we paint indoors or on excursion? If we are going out, Where are we going? What will we be painting? Can we choose what to paint? The intentional vagary bothered some of our fellow students. Answers to these questions were occasionally demanded. I was exhilarated.

Each day unfolded magnificently. Early in the morning we had time to do as we pleased. I would wake early to take a dip in the sea, sketch or paint, and take a walk to town for a fresh baked spanikopita or Greek yogurt with honey. Classroom time was dynamic. Jun-Pierre would instruct on a topic of focus and provide a variety of hands-on exercises. For example, on the class period focusing on color Jun had us create a variety of color wheels using a particular color family and using a variety of wet and dry brush techniques. After creating these wheels he had us wash over them with various colors to understand their effects. We would break from one in the afternoon until four-thirty. We could do whatever we wanted during the break. Many of us chose to eat lunch at our designated cafe, Cafe ???????? (Distrato). Some of us would then swim, shop, or nap. Often for the resumption of class we would take an excursion to someplace on the island such as a superlatively beautiful hillside, monastery, or windmill overlooking sea and rock where we would practice applying the day's classroom instruction. In the evening there was often an optional lecture offered by a professor at the Aegean Center. Night would mean dinner on our own, perhaps a final night swim under moonlight and then sleep. Sleep! The kind of sleep that comes quickly to those who are satisfied, exhausted, and content to be lulled by soft breezes and the sound of the sea.

After our second week of studying, exploring, and tasting something wonderful happened. We were more relaxed, our personalities had settled in to one another. I gathered the distinct sense that it became less about what we expected from the class and more about being able to absorb everything we were being offered. Our work reflected this. Our conversations and deportment reflected this. We had a rhythm and a little livelihood on Paros, no matter how transitory. Rather sadly, following our student show it was time to leave.

We came by boat and we left by boat. New York and the old life was calling. It was time to strip myself of my Greek sandals and my responsibly cultivated tan to once again return to pushing my plow through fields of ones and zeros. And after so much! I had eaten incredible locally grown food. I had mastered zigzagging from shadow to shadow in order to avoid the summer sun. I had learned how to draw, to paint, to see. Now, it was time to return. I may not always have fresh urchin roe, but I'm forever changed. I know because I did not merely visit, I had emigrated--even if it was only temporary.

The ferry approaches on the horizon. Hot people queue haphazardly in bunches, luggage awkwardly in tow. Up until the last moments there are kind words, embraces, and well wishing. It is unlike air travel: the airline security acting as a hermetic seal between your destination and airport-land and all airport-lands connected by flying tubes of recycled air. With air travel you enter on one side of the tube and come out uncomfortably on the other. This produces an illusion that destinations belong to differing neighborhoods within a grand scale world-metropolis. Objects seem closer than they appear. Traveling by boat is different. Up on the deck of the boat you can see the land and your loved ones standing there, all getting smaller and receding slowly into the distance. They recede just as slowly as the thought, wouldn't it be great if I could stay forever?

Continuing on the series of North Short Polaroids, here is a shot I took outside of Grand Marais. I drove my car over a little rise and found where all of the above-ground gas storage tanks must go to die.

I was going through my box of Polaroids this morning and I found a number of prints that I had intended to post but had not.

This image was taken during the same trip as this image. It taken in early March, nearly two years ago. I was driving alone down the Gunflint Trail and around a bend I saw this logging yard.

There were many wonderful photos in that old Wisconsin beer box. This might be my favorite. It is my mother and her duck in South Minneapolis. The border of the picture reveals the year: 1962

Funds raised during the Sleep Out allow IOCP to respond to more than 1,800 emergency housing crises...Every month, IOCP turns away about 20 worthy housing requests because of lack of funds.

If you'd like to donate to this cause please see: https://iocp.ejoinme.org/?tabid=220097&joinme=2087

andrewzimmern Andrew Zimmern

A pic from my pal @Jordan_Husney’s meal @ Wondrous Awful Kitchen in MPLS. You cant make this crap up. http://twitpic.com/2xcbyq

The previous entry was taken and processed by this man. I loved his camera, I loved his attire, I loved his manner but most of all I loved his face. It reminded me of the eerie cartoon faces from Têtes à claques.

If you are unfamiliar with Têtes à claques you should watch this clip. Even if you don't understand French the Québécois is punctuated with so much English that it's not that hard to understand. C'est pas beautiful?

Back in June I had to travel to Paris for work. I love traveling to Paris: one, I love the city and two, I have good friends there.

My friend Mika lives in the first arrondissement. When I go to visit her it feels more like visiting family than friends. I've shown up sick, been mothered and healed. I've had my face stuffed with pâté, wine & cheese. There are sisters and brothers and children and friends. It's a very lively place. Being a bit of a nomadic hermit, I crave this kind of environment from time to time. I'd come lonely and leave with a warm heart and a new book to read.

Mika's boyfriend C is one of the coolest men on the planet. He's who I want to be when I grow up. He's incredibly kind, handsome, deeply thinking and creative. Children love him. It seems as though he never lost the way children look at the world and yet he developed the full emotional and spiritual maturity of a Zen master. I enjoy spending time with him, hearing his travel stories and trying to see Paris as he sees Paris. He makes me want to improve my French.

There was an arts festival in Paris where artists opened up their apartments to show where their workspaces and art. C and I took in a few of these places. Along the way we ran into a photographer who had constructed his own camera. For ten Euros he would snap your pictures (using his hand as the shutter), develop a negative print, snap a positive print using the same camera, and give you the resulting image. I could n't resist!

The image above was the result of his process. I couldn't be happier with it! It was rainy and humid. I felt like waterlogged cardboard. I look like waterlogged cardboard. This photograph represents a wonderful memory.

Over the past several years I've had more and more opportunity with my employer to speak at trade events, conduct training sessions, and give webinars. When I was in New York last weekend I commissioned a photographer for a corporate headshot.

The photographer, Daphne Borowski, did a superb job and turned around the images in just a couple of days. I had over 100 shots to choose from.

I winnowed down the images to five candidate images and enlisted my family for help. I asked them to pick their top two favorite images. My brother took one of the images and replied saying, "I much prefer this."