Apr 03

Arduino and EL Escudo

Another fixit type post.  Every so often I repurpose my Arduino and EL Wire for a new project, and each time I always forget how to properly get the EL_Escudo library resetup.  I should probably just fork the code on GitHub with the fixes that have been posted, but who remembers to do that.

So, the EL Escudo is a cool shield for the Arduino.  SparkFun sells it.  I highly recommend them.  There is a small bug in the library code that is fixed by bobmct’s post (http://www.sparkfun.com/products/9259#comment-4eaad859757b7fd35100ba5d):

“I realize this is a rehash of what others above have said, but I got mine to work by doing the following.

Getting the El Escudo to work
Two problems:
1. Must fix a mistake in the library code: Needed to make in EL_Escudo.cpp (thanks BMK):
void EL_EscudoClass::on(char channel)
pinMode(channel, OUTPUT);
digitalWrite(channel, HIGH);
void EL_EscudoClass::off(char channel)
pinMode(channel, OUTPUT);
digitalWrite(channel, LOW);
2. They also recommend GND and HVGND are tied together. Look at photo (thanks miku) http://dl.dropbox.com/u/3551240/el-escudo.JPG . With the code change made above I also tried to see if the El Scudo would work without this jumber (between GND and HVGND), and it did work and it did work without it. I was using the EL_Blink.pde example when testing this.
The above got things to work with a handheld 3V inverter (two AA battery powered) with the button pressed 3 times (a steady AC supply, no blinking) with the output of this inverter connected to the El Escudo shield’s “EL Driver Inverter Ouput” JST jack.
The Arduino was powered from a 5VDC wall transformer (1A capacity) with the barrel jack plug connected either on the Arduino’s barrel jack connector or connected to the El Scudo’s “EL Driver Raw Voltage” JST connector.
You will need to fabricate the strange El Wire plugs to JST plugs to make all the connections. In my experience above, the polarity was not a factor because the output from the inverter is AC and so is the input to the el wire.
Hope this helps.”

My only issue was with number 1.  Fixing that caused the main library to work again.

With the upgrade to Arduino 1.0, WConstants.h will throw an error since that isn’t being used anymore.  You should be able to safely change all WConstants.h to Arduino.h


Mar 27

PhoneGap 1.5.0 and iOS 5.1

Hey All,

Just posting here so I remember some fixes I had to do with the new release of PhoneGap 1.5 (also known as Cordova).

When you initially run your new xCode product, you will get a ton of “semantic” issues.  The fix is to go to Build Settings -> Objective-C  Automatic Reference Counting -> “NO”

I found this clarification from a comment posted by Alejandro Orduz at http://phonegap.com/2012/03/06/phonegap-1-5-released/ 

“ok, i manage to make it work, Cordova, under Xcode 4.3.1…. regarding the www stuff…

First of all, getting into this painful process(more of all because of my lack of knowledge of Xcode), i wen to the process to upgrade my iPhone to the latest iOS 5.1, then had to upgrade Xcode to 4.3.1 to support testing in this device, but also did an upgrade to the latest lion 10.7.3…. so it was a boring weekend of upgrading….

The first time you run a new phone gap project under Cordova, is not like old days, now when you run you get a scary 9 errors warnings about a Semantic Issue in some, NSAutoreleasePool well, for some of us, that is like speaking chinease… but it can be solved very easy… the new Xcode has some Automatic Reference Counting ON by default, so you just go to the project Build Settings, find Objective-C  Automatic Reference Counting and change it to “NO”, after that everything goes to normal…. then it can build, add the www, you get the normal iPhone simulator error, and then, like before, had to drag and drop the www folder into the project root….

Changes like this are very scary for people like me, that found phonegap an amazing tool to build mobile apps with our web development knowledge…. :-{  ”

Also! I finally got the camera example working.  I was receiving a weird “wait_fences: failed to receive reply: 10004003” when I used the Camera example code verbatim.  It would work, but I would only recieve a small blue box on my iPhone.

The issue is that the code on line 40:

smallImage.src = “data:image/jpeg;base64,” + imageData;

is wrong.  PhoneGap 1.5 / iOS 5 stores the taken photo in a temporary directory, so you dont get the base64 data anymore, you have the actual URI for the photo in imageData.  All you need to do is change line 40 to be:

smallImage.src =  imageData;

and it will work.


I hope this helps out some people.  It’s working for me, YMMV.


Mar 15

PyCon 2012

I’m going to start this blog with an account of my recent trip to PyCon 2012.

My University sent me there to learn, network, and be a representative.  I had a blast.  I have learned an immense amount and met an amazing group of people.

There were 2500 incredibly bright and talented individuals at this event.

To those who could not make it, PyCon has made available recordings of all the sessions at: Pyvideo.org

One of my favorite session talks: Building A Kinect Game With Python

I also have exported my bookmark list.  During the event, whenever someone mentioned any neat tool, company, or site, I went there and bookmarked it.  There are some python sites, some music sties, some random sites, and some fun sites.

You can find my bookmarks here: PyCon 2012 Bookmarks