Spent the day working with DS18B20 temperature sensors and getting an Arduino to read the data they spit out.  Lucky for me and you, we have the shoulders of giants to stand upon as we copy and paste some magical code to get us started!

DS18B20 Temperature Sensors + Arduino from Morgellon on Vimeo.

The DS18B20 is a small 3 pin temperature sensor that closely resembles a transistor.  Each one has a “unique” 64bit serial code and can communicate over a “1 Wire” protocol.   With a bit of code, we can have multiple temperature sensors all communicating and sending data over just one pin!

I’ve taken some pictures of my project today.  I have three DS18B20 all communicating over pin 10 on an Arduino.

The first, or closest to the Arduino, is wired in “Normal” or “Master” mode.

• GND(pin1) to Arduino GND
• DQ(pin2) to Arduino Pin 10
• VDD(pin3) to Arduino 5V
• a 4.7K Resistor between DQ(pin2) and VDD(pin3)

The last two, or middle and furthest away from the Arduino are wired in “Parasitic” or “Slave” mode.  These two require no power (as their name sake implies).

• GND(pin1) and VDD(pin3) to Arduino GND
• DQ(pin2) to Arduino Pin 10

The bit of sample code scans through the DS18B20 64bit serial codes until it finds no more unique codes.  It displays the information in HEX, followed by Celsius, then Fahrenheit of each sensor before moving to the next.

Download the code used in the example here:  http://serverwillprovide.com/icuubi/examples/multiDS18B20.pde

Read more about the DS18B20 Temperature Sensors and the Arduino!

• http://www.arduino.cc/playground/Learning/OneWire
• http://datasheets.maxim-ic.com/en/ds/DS18S20.pdf
• http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1161557194/75
• http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1199313338/0

Finally gotten around to posting some pictures and video from the Flourish Conference, in Chicago IL.  Flourish was a blast, Droops and I had a wonderful time with all the great people that we met.

Massimo Banzi at Flourish ‘09 from Morgellon on Vimeo.

Processing Workshop at Flourish ‘09 (pt1) from Morgellon on Vimeo.

Processing Workshop at Flourish ‘09 (pt2) from Morgellon on Vimeo.

There has been quite a flurry of development revolving around the official ethernet shield recently. Here are what I consider a few of the more important changes.

Ethernet fixes – There are some connection issues with the ethernet library with regard to incomplete disconnects. Since the wiznet chip only supports 4 simultaneous connections, this manifests itself pretty quickly if you are trying to poll a server for changes. Etracer, from the arduino forums, found and fixed this problem and has released a new client.cpp as well as detailed the issues in a post to the arduino developers mailing list.

Another recent addition is Ben Combee’s Webduino library, which greatly simplifies processing html forms when using the arduino and ethernet shield as a web server. The library and basic examples are available at: http://code.google.com/p/webduino/

Bjoern Hartmann’s UDP library has also been used for a couple of recent projects including work on DNS/DHCP and fellow Infonomicon member Cynshard’s work on a NTP library. The NTP library is particularly useful since it can be combined with the software Date/Time library to have fairly accurate time without adding a hardware realtime clock to your project.

As you can see, there seems to be a lot of development activity ongoing for the official ethernet shield and since the addition of networking to the arduino greatly expands its possible uses, I think we’ll see even more. Please remember to thank these folks for their code and bugfix contributions…

What a short strange trip its been. I work at a small private military school with a really fun summer camp/school program. I asked the principal the other day if I could teach an Arduino class this summer, fully expecting to have to explain what it was and how I would do it, and he looked at the syllabus and said that it was cool.

I am teaching an Arduino class for High School Credit!

Then we went to Flourish ‘09 in Chicago and met Massimo, one of the founders of the Arduino project.  (pics and video to come).  He was excited about this class, saying that we needed more english language lesson plans for the Arduino.  So not only am I teaching a really cool class, I am going to be helping with making lesson plans for teachers to use the world over.

So what about this class, what is it all about?  It is an Innovation and Invention credit in 6 weeks, or half a credit in 3 weeks.  I am going to guide the students in building what they want to create, which should be really fun.

Here is the class website and syllabus.

Now we just need a few students.  My school prides itself in small classes (10/1 teacher ratio’s) which would be awesome for this type of class.