26 May 2010

VectorNav Sensor

I soldered on the VN-100 AHRS (Acceleration Heading Rotation Sensor) from VectorNav. I've setup the sensor to output the yaw, pitch, and roll since I need that information to steer the payload module during its descent. You can see that the yaw, pitch, and roll are output in a NMEA formatted sentence in the picture below. The sensor has 3-axis accelerometer, magnetic sensors, and 3-axis gyro that it uses to create the yaw, pitch, and roll.













































The Honeywell IPT sensor also arrived in the mail today. It's much smaller than I expected and the protective cover on the pressure sensing tube is...well...interestingly shaped... Hopefully over the weekend I'll be able to put all the functions together into a nice data logging package and get started on the servo controls.

23 May 2010

RRRRRUUUUNNNN!!!!!!

UThe trap was set. A man with an orange ribbon watched from across the street as four men with blue ribbons jogged past. He sprinted across the street splitting the group of blue, three ahead and one behind. With a skidding stop the one behind barely missed being tagged and bolts like a startled gazelle in the opposite direction, isolated from his friends. The chase ensued as his three friends looked on, cheering for escape. Down the busy D.C. street, across and up the other side at an all out sprint they went. At the top of the block fortune smiled on the blue runner as another slower blue ribbon came around the corner and the attention of the orange chaser was diverted. Escape! Back to his friends, exhausted, exhilarated, and ready to survive D.C.
This is my story from two weekends ago when I promised that I would have GPS tracking ready. Since I was frustrated with the uM-FPU issue I decided to enter the annual Survive D.C. challenge instead. It was a great time, and I have my strategy set to win next year. As for GPS tracking I just figured out (literally five minutes ago) that the chip selects for my uM-FPU code were setup improperly. Somehow I inadvertently changed the fpu_spi.S file and it screwed everything up for me. Many thanks to Cam at Micromega for his debugging help! Now that I have it working it should be a quick coding session away from KML track files stored on the SD card. Maybe you'll even get two posts in the same day out of me...

UPDATE!!!!
I decided to just update my post instead of making a new post. Below is a Google Earth view of a track I took. I actually walked around the parking lot in a loop, so the track isn't very accurate. The KML file created by the balloon hardware is below the Google Earth picture. The KML format is very easy and you can probably figure it out on your own. If you're struggling check out the KML Tutorial.

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11 May 2010

Where am I, literally?

The uM-FPU's are up and running and so is my GPS receiver. I used the NMEA sentence application note on the micromega website as the basis for a user defined function inside my uM-FPU. The function collects a PUBX, 00 NMEA sentance from the GPS receiver and breaks down it's fields to be stored into the registers of the uM-FPU. The code is working when I load a test sentence into the uM-FPU manually, but there is an unknown problem getting the actual data from the GPS receiver into the uM-FPU. It's getting a bit late, so I decided to find the problem tomorrow. Below are some pictures of the output with the test sentence and the output of my GPS receiver. I'm right on track for my XML output at the end of the week.


09 May 2010

Look Mom, no hands...because soldering irons are hot. Safety First!

Well, after the last circuit boards and their soldering problems I decided to go back to the basics. You can see my classy soldering workspace/kitchen. I used lead free solder, don't worry.


So, like I said...back to the basics. Instead of using a whole loaf of bread while soldering, this time I used bread flour! Let me tell you, it made all the difference. Choosing a 100% organic bread flour gave my soldering that earthy, healthy taste too. All kidding aside there were no problems getting this soldered together and my initial tests were great! I've managed to get both micros running with the desired settings, both SD card slots work as you can see in the picture below, and I'm working through the code for the uM-FPU floating point co-processors now. I should be logging GPS tracks to the SD cards in XML format by the end of the week.


My co-pilot, Arhan, and I have both purchased our airplane tickets for Billings, MT. The flight will happen either on Saturday, July 3rd at 1PM or on Sunday, July 4th at 8am. The location will be one of the three previously discussed. It's really too early to know what the weather will be like. It would be great to have a ton of people show up and help, so if you're at all interested leave a comment and I'll keep you posted on the exact details. Happy Mother's Day Mom!

06 May 2010

PCB's Are In!

The new PCB's are in and they are stylish! I chose to do a white solder mask and black silk screen. They look so good I'm going to make it my new signature colors. These boards were made by Colonial Circuits in Fredericksburg, VA. I highly recommend them for your circuit board needs. I'm always ordering small quantities and their prices are great for the complex boards. They also ship out the yield from the whole panel even if you only asked for one. If you're looking to have a new board made send your gerber files to Beth at sales2@colonialcircuits.com. I should have these babies soldered up and working by the end of the weekend, so I'll leave it here for now. Enjoy the pics and try not to be too jealous!

03 May 2010

One Bad Apple is All it Takes

It's always been a dream of mine to own a company. There's the trill of being in control, fighting to keep everyone paid, and of course my company would be technology centric so I could be on the cutting edge. I realized today that one bad employee, at any level in the company, could ruin the whole thing. Part of this realization came from my new set of bicycle rims being stolen and the other part came from some record breaking NASA news.
The bicycle rims were a birthday present from my parents. They were being FedExed to my apartment and I've never had any issues with deliveries there. Now, bicycle rims aren't small, the box measured 3 feet tall and wide. When I saw the tracking information claiming the package was delivered I expected to find the rims at the front office of the apartment complex. For some reason the FedEx driver left a small package at the front office and decided to leave my giant package at the front door of my apartment. Of course the package was stolen, because one bad apple didn't care enough to think it's foolish to leave packages out in an apartment complex. I don't have a signed agreement with FedEx allowing them to leave packages, so this has reflected very poorly on the company in my mind.
The NASA news is that the Spirit rover on Mars is about to become the longest running program on Mars. Both Spirit and Opportunity were designed to be 90-day missions, and they have both survived more than 6 years! The engineers and crew for these two missions have done a fantastic job! The bad apple side of this story is in the way NASA has taken engineers and mission crew like this and ground them into the pavement with terrible management practices. Granted this problem involves several bad managers, but it had to start with one bad policy decision.
The second revision of circuit boards for the balloon are due in this week, so look for a good status update next week or this weekend. I am tentatively planning to launch on the 3rd of July from a location close to Billings, MT. I will post the exact launch date and time as soon as I get all of my crew to buy their plane tickets. Anyone who wants to help of observe is welcome to show up. Science is always more fun with a group of spectators to see your fantastic failures! Check out the latest NASA balloon project in Australia for a worst case scenario of what you might see at my balloon launch.