ra726

Last year I bought a Panasonic Lumix DMC-ZS3 (also known as the DMC-TZ7) and have loved the camera. It has an amazing 12x zoom, takes great pictures, and does 720p video. If you are in the market for a camera, I would recommend the new version of it, the Lumix DMC-ZS7 which has GPS tagging and is currently cheaper on Amazon.

About a month ago, I cracked the screen on it. The camera still worked, but since there is no viewfinder I could never see what I was getting pictures of or adjust any settings. It made it really hard to get good pictures, especially when trying to use the zoom.

I ordered a new screen from http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=220639262841 and it works great. If you need a screen for this camera, I would recommend buying it there.

It is a bit tricky to replace the screen though. Luckily, I found a video that shows all the steps. The text is in German, but you can see all the steps which is all you really need.

The only difference I found from this video was that the screen I bought did not have the metal bezel around it that the one in the camera and in the video. All I had to do was remove the bezel and put it on the new screen and it follow the rest of the steps the same as the video.

Total it took me about 20 minutes to replace the screen, and then it was working perfectly.

While working on Flying Pie Notifier, I ran into a problem with Gmail marking the notification emails as spam. I was able to find the Gmail Bulk Sender Guidelines and make some changes. I think I got Gmail to finally recognize that the notifications are not spam.

My first step was to make sure that SPF was set up correctly and to check the reverse DNS PTR record for the IP address I was sending from. Both of these are simple to set up with just DNS records.

Unfortunately, those changes didn’t seems to fix the problem completely, so I had to move on to the next step, DKIM (DomainKeys Identified Mail). DKIM is a way of cryptographically signing emails that are sent to verify that they are sent from the domain they claim they were sent by.

I found a PHP library called PHP-DKIM that would perform the signing, but it was incompatible with the PEAR Mail_Mime module that I was using to send HTML email. I had to make some modifications to the code to get them to work together.

Here are the steps I used to set up DKIM signing with Pear::Mail_Mime and PHP-DKIM:

1. Generate a public and private key pair.
   First I needed to generate a public and private key pair to use for signing messages and for other people to verify the signature. These commands generate 2 files, key.priv and key.pub, containing my new private and public keys:
   
openssl genrsa -out key.priv 384
openssl rsa -in key.priv -out key.pub -pubout -outform PEM

2. Publish the public key in a DNS record.
   DKIM public keys are published in a special DNS record so the recipient can look up the key and use it to verify the message signature. I followed the PHP-DKIM README and put my keys in a dkim-cfg.php file along with my domain name and a selector name and ran dkim-test.php.

   Loading dkim-test.php will tell you if you have any problems with your configuration so far, and if not it gives you a DNS record. For me, it generated this record which I added to my DNS:

   p._domainkey.flyingpienotifier.com. TXT "v=DKIM1\; k=rsa\; g=*\; s=email\; h=sha1\; t=y\; p=MHwwDQYJKoZIhvcNAQEBBQADawAwaAJhAODvTnvu4+OO+47m/3iRImsshlhQ+u30 0cHSdCJPndsD2meo63lNl8ELktIZKUEEEGFYNbwuZHWISCmuFHEiQNIHeag+awen 75oPBZqd1ABVdjyTwZa1matMzQhg5rSGpQIDAQAB \;"

   I then used http://www.sendmail.org/dkim/checker and http://domainkeys.sourceforge.net/selectorcheck.html to check my record and make sure it was set up correctly.

3. Signing Code
   I had downloaded the PHP-DKIM library from http://php-dkim.sourceforge.net/, but found that the way it treated headers was not compatible with the PEAR Mail_Mime library that I was already using. PHP-DKIM expects a single header string formatted the way headers are transmitted between servers when sending email. Mail_Mime wants an associative array of headers that it then uses to generate the header string when it sends the final message.

   I decided to modify PHP-DKIM to get it to work with the associative array approach, since I thought that was the better of the solutions.

   You can find my modified version of the library at http://www.ra726.net/php-dkim.zip. The only file I modified is dkim.php. I changed to use an array for headers and cleaned up the code a bit to make it easier (in my opinion) to read.

   To make the library work with Mail_Mime header arrays, I added code to the AddDKIM method that concatenates the headers together. This is simple in PHP, and just requires:
   
$headers_line = '';
foreach ($headers as $key => $value)
$headers_line .= $key.': '.$value."\r\n";


   After that, I just had to change what the function returned. Instead of returning a new header string, I just return the DKIM signature string. This can then be added to the headers using:
   
$dkim = AddDKIM($headers, $subject, $message);
$headers['DKIM-Signature'] = $dkim;


   This code could be cleaned up to automatically add the header, but it works until I take the time to rewrite the library and make it object oriented.

4. Testing
   When I first tried to use my new code to send emails to my own Gmail account, I found that I had some errors in my implementation. In Gmail, you can see the full headers and the results of DKIM and SPF checks by clicking the arrow next to Reply and selecting Show Original. This will show you the full headers of the message, including the verifications added by Gmail.

   When I did this on my message, I got an error telling me the body hash was wrong. The body hash is used to verify that the email message was not tampered with during delivery. Since I had sent the message myself, I knew it had not been modified. Therefore, Gmail was calculating the hash based on a different version of the message than my current code.

   I was able to find a service that could help me track down the problem. At http://www.port25.com/domainkeys/ you can find information about an automated responder that will let you know the results of the DKIM verification.

   By sending my message to the Port25 reflector test address, I got a report letting me know all the details of the DKIM verification process. One of the pieces of information in this email was the canonicalized body of the email. Canonicalization is the process of standardizing the message to specific requirements to make sure both sides are doing the hash calculation on the same data. I could then use the NiceDump function in PHP-DKIM to print out the canonicalized message that I was calculating the hash on. This let me see where I had caused a problem when modifying the library.

   Using the same testing address, I was able to find a few other problems with my modifications to the library and get it working. Once I had the bugs worked out, the reflector address reported the DKIM verification as passing. It worked!

There is no definite solution for not having your emails marked as spam. All you can do is try to follow all the guidelines that Gmail and other providers specify. It seems to me that Flying Pie Notifier is no longer being marked as spam, so I think I should be good for now. DKIM is a part of that, but I also had to make sure my mail server and DNS records were all set up correctly.

If you want a really detailed technical explanation of DKIM, you can find the specifications in the RFC at http://www.dkim.org/specs/rfc4871-dkimbase.html

If you have any issues with this code or are trying to implement it yourself, leave a comment and I can try to help you out.

Introducing my latest website project: Flying Pie Notifier.

If you aren’t from Boise, Flying Pie is an amazing pizza place and has been my favorite for years. In addition to having amazing pizzas, they have something called It’s Your Day. Each day they have a different person’s name. If it is your name, you can come in and make your own pizza.

I did It’s Your Day a while ago and had a lot of fun. But I always forgot to look online and see when my name or my friend’s names were coming up. So I decided to make a website to remind myself.

Right now, you can go to FlyingPieNotifier.com and sign up. Just enter your email address and the name you want to be notified about and you will get a notification sent to you when your name is coming up. You can also sign up to get a weekly reminder of the It’s Your Wednesday group (and maybe some other things soon).

I am working on adding in some extra features, so let me know if there is anything you want. I would love to hear any comments or suggestions.

For my birthday this year, my wife got me the Arduino Start Kit from Adafruit Industries.

If you aren’t familiar with Arduino, it is a great open source platform for doing small electronics projects. The start kit I got has a Arudino Duemilanove, which is the latest basic version of the platform. The Duemilanove has a small processor on it that can be easily programmed over USB, and a lot of input and output pins to play with.

After getting the kit set up and my prototyping board soldered together, I decided that my first project would get seeing if I could get some old 1-wire temperature sensors working. A few years ago, I got a sample of 5 of these sensors but was never able to get them working with my homemade serial adapters. The sensors I got are the DS1820 from Dallas Semiconductor. These are old and have now been replaced by the DS18S20, but they work the same.

Turns out that the Arduino community had already done all the hard work at getting these working, so it only took me a few minutes to get it set up.

Hardware: Each of these sensors has 3 legs: power, ground, and data. If you are only using a few sensors that are close to the power supply, you can instead use parasitic power as I did. This reduces the number of wires to the sensor needed to 2, data and ground. To do this, I shorted the power and ground pins and wired them to ground. I then attached the center data pin to one of the digital IO pins of the Arduino.

Here you can see the Arduino with the sensor connected on the prototype shield from the starter kit.

This is a close up of the connections. The brown wire connects the power and ground pins. The black wire connects these to ground. The yellow wire is connected to digital I/O pin 2 on the Arduino.

Software: The Dallas Temperature Control Library is a library that allows simple control of the 1-wire temperature sensors. All you have to do is download it, put it in your Arduino libraries folder, and open the Simple example.

The example sets up the library and reads the current temperature from the first sensor, printing it out to the serial monitor.

After years of having these sensors sitting around in a drawer, it only took me a few minutes to get them working. Now I just need a larger project to use these in.

Well it has been almost 3 years since I last blogged, but now that I have graduated I am going to try to start again.

I have decided to start posting again about all the projects I am working on. I always seem to have a few things going on, but I rarely record anything from them. To help myself keep track of it all and maybe help anyone doing something similar, I will be posting updates about my different projects.

I have a lot of different things going on right now, so over the next few weeks I will start cataloging some of them here. Then I can start updating them as I make progress.

Hopefully having graduated and having a purpose for this blog will help me to stay more consistent and keep posting.

I have been working through The Hazy Mind XNA tutorials at http://www.thehazymind.com/XNAEngine.htm.

The computer I have been using for development is my old laptop that has a Intel 915 GM. This card has integrated pixel shading, but relies on the CPU for vertex shading. It also has some other issues, but I won’t go into those now.

As I went through the tutorials, I was having issues rendering the textured quads that are the first object made and rendered. These quads are also used to create the skybox, so getting them working was required to continue developing through these tutorials.

These two pictures show the issues I was having. The first picture shows a single triangle not rendering correctly, and the second shows two triangles not rendering.

After quite a few tries, I finally discovered what the problem was. In the tutorial code, the Index Buffer is created using:


int[] inds = { 0, 1, 2, 1, 3, 2 };

myIndices = new IndexBuffer(myDevice, typeof(int), 6, ResourceUsage.WriteOnly, ResourceManagementMode.Automatic);

myIndices.SetData(inds, 0, 6, SetDataOptions.None);


In this, each of the indicies is represented by an integer. For some reason, using ints causes the rendering errors. By looking at other tutorials, I found that many of them used shorts instead (A short is just an integer that uses less memory and stores a smaller range of numbers).

To fix the errors, all I had to do was change the code to:


short[] inds = { 0, 1, 2, 1, 3, 2 };

myIndices = new IndexBuffer(myDevice, typeof(short), 6, ResourceUsage.WriteOnly, ResourceManagementMode.Automatic);

myIndices.SetData(inds, 0, 6, SetDataOptions.None);


Here is the final result. You can see that the rendering problems are gone.

I’ve been working the last week on getting started with XNA and how to port AquariusSim over to it. Learning XNA has been easier than I expected it to be since I had already written a lot of code in DirectX9.

Microsoft did a good job with most of XNA, but there are a few things that I think will really frustrate new developers. Getting started has been improved a lot. It now only takes a few lines to set up a device and render a blank screen. That was one of the things that took me the longest when I was starting to learn DirectX. Most of the complexity of setting up the device has been hidden, which makes it a lot simpler. It might end up making some advanced features harder to implement, but I am not sure because I never used any of them.

Switching to fullscreen is also a lot easier. When I was working on the first version of AquariusSim I remember spending days working on getting that to work, but its now just a few lines of code.

The one thing I like the least about XNA is the removal of the Fixed Pipeline. The Fixed Pipeline in DirectX allowed you to render objects using simple Lighting Objects and not have to worry about learning another programming language to implement shaders. XNA has removed this functionality and requires shaders to be written for everything. This means that the programmer has to either learn a completely new langauge, or they have to just use other people’s shaders without understanding how to change them. This could end up being a serious block to new game developers.

Overall, I think Microsoft made some really good decisions for XNA and I think that for someone experienced with 3D graphics it will be an easy switch. But as before, there are some serious roadblocks that could make aspiring game developers give up before they get very far into it.

Now, back to working on this port. Hopefully I should have some screenshots up soon and maybe even some code examples of what I am doing.

We have just opened up sign-ups for the beta of in480.com. in480 is a new online speed dating website where you can meet people to date or just as friends. Our matching system matches you with people who you will be interested in and gives you tips to get the conversation started.

If you sign up on our website, you could be one of the first people to be able to experience this new website that I have been working on for the last few months. Over the next few weeks I will be posting more about our progress and what is happening with the site. We will also be trying to get a developer blog set up where the other people working on the site can post as well and I will provide a link to that from here.

In the meantime, go over to in480.com and sign up to get an invite to the beta.

If you talked to me a few months ago, you will know that I was working on a game using C# and DirectX. The last few months have been pretty busy so I haven’t worked on it in a while, but I am going to start trying to convert it over to XNA.

XNA is the new version of managed DirectX and will allow me to (once I get one) port the game over to the XBox360 pretty easily. Since Microsoft is moving all of their development over to XNA I figure it will allow me to avoid work trying to move over to it later.

I am going to be learning XNA through some tutorials by the same person who I got a lot of the code for the first version from. You can see the tutorial on his site at http://www.thehazymind.com/XNAEngine.htm. As I go through those, I hope to also start my own series of tutorials or at least walk-throughs of how my development is going.

For those of you who don’t know, the game is going to be a simulator similar to the SimCity line of games. The difference is that I am basing it on the idea of Aquarius from the book The Millennial Project. This means that the game will consist of managing a floating island city.

I will be posting more about this as I continue working on it, so look for more soon.

Well, after years of thinking about it, I have actually set up a blog. And for the first time since the old site (or a blank white page) the ra726.net domain is actually being used.

I am going to start using this to keep track of all my various projects and get some feedback on them. Maybe this will actually motivate me to finish some things I have been working on for a while .

(And yes, I know that I need to do more work on the style of this site. But at least I didn’t just leave it completely default)