Slacklining

Posted on 2009-07-08 by Nigel VH

For those who’ve been waiting, here’s a couple videos of me slacklining and attempting jumping on, or as a long time friend calls it, “The Flying Mount.”

The first one is of me failing a bunch of times. The second is of me finally succeeding!

Video_09

CIMG0164

For those who are interested in the mechanics of the html video tag, and use in FireFox, here’s a few things I’ve come across.

First, nobody likes autoplay. Thus, there’s a control for that. According to some sites, and logic, you would add “autoplay=’false'” to the video tag. Unfortunately, that doesn’t seem to be the case. Apparently this is what they like to call a “boolean value” by which if you specify anything for autoplay, it takes it as true and will autoplay. So if you don’t want it to autoplay, don’t specify it.

Secondly, I’ve had a rather difficult time finding reasonable converters from x video format to OGG Theora. For you linux users, you can use ffmpeg2theora. (For you debian and ubuntu users there’s an apt package of the same name.) That will convert most anything to OGG Theora. It’s what I use.

Third, and partially related to number two, apache2 by default doesn’t recognize .ogv (.ogv is what ffmpeg2theora gives as an output) as an OGG format file, and thus doesn’t relay the proper mime data to FireFox. You can either force it with a .htaccess file, or just rename the file to .ogg. This second option is what I’ve done, and it makes it work.

Good luck!

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Ham Radio

Posted on 2009-06-29 by Nigel VH

Well, I finally got one. I’ve been a licensed operator for well over a year now, and I finally got around to getting a radio. It’s a Yaesu FT-8900R which for those who don’t want to take a look at the link, or don’t know already, is a mobile quad-band FM receiver.

Since the last few blog posts have been relatively picture lacking, I’ve documented my excited opening of the radio and it’s associated parts. Here are the pictures!

In addition to all of the great stuff that I got new from Ham Radio Outlet (yes, I know the site is cloogey, It took everything in me not to email them and offer to fix it), I also got an old SWR/Power Meter and a Pre-amp from my Dad, who had recently found them in a collection of my passed grandfather’s old things. I haven’t had a chance to test the pre-amp, but the SWR meter works, and it’s nice to be able to use some of that equipment which has a bit of family value.

I haven’t had a whole lot of time to play with it yet, but that’s the plan for this evening. Anyway, in the short time I have played with it, I’ve been able to pick up quite a few things around the Seattle area. I think I’ve gotten police radio, a towing company, and King County Metro. So there’s always interesting things going on.

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Truck Optimizations

Posted on 2009-06-22 by Nigel VH

This weekend, I got a little bit of spare time, and went outside to enjoy some of the nice weather and work on my truck a little. In addition to the standard checking of the fluid levels, throwing away all the trash, etc. I decided to take a little time and redo some of the work I’ve put into the electrical system in the past, and if you know me, you know that it’s probably fairly extensive.

Well, it was. There are a lot of little things, but there are a few primary things I did. I rerouted the antenna feed line for the CB radio through the firewall, so that it wasn’t wrapped around the sharp angled door jamb.

I re-ran the power for my relay system so that it would automatically shut off after the ignition gets turned off. This lets me make sure not to drain my battery in case I leave the amp or my power inverter on.

Last but not least, I fixed my amp. It “broke” a little while back, and I’m not sure exactly why, but when it broke, it sounded a lot like a recurring problem I’ve had with the gain adjustment potentiometer. It was an old electrically noisy pot and when you’d turn it, the amp would go berserk and make not happy noises come out of the speakers. So I took the amp apart and went over the circuit board and re-soldered some of the connections. There were several connections that looked pretty bad, so these could also have been at fault. Anyway, I measured what the resistance of the pot should be at approximately half gain, which is where I kept it most the time anyway, and then replaced the pot with appropriately rated resistors. It seems to work now, so hopefully I’ve fixed whatever is wrong with it, and I won’t accidentally hit the gain knob and make it make very loud unhappy noises.

In other news, I chatted with a buddy of mine yesterday who’s come across some interesting plans on the internet for an interesting very basic, and very low cost HAM radio receiver. He’s gotten the idea to replace the frequency crystal in the design, with a frequency generator IC, and control that with an Arduino microprocessor. That would allow a digital readout of the frequency you are listening for, and allow it to be adjustable (in his version) from about .2 MHz to about 50 MHz. I’m interested in seeing how well this works out for him. There are a lot of interesting things down in those frequency ranges. If it works well I may have to build one. Generally I play in the 144 – 430 MHz ranges, so it would be interesting to see if I can find a frequency generator IC that would work accurately at those frequencies.

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ESS205 – Access to Space!

Posted on 2009-06-06 by Nigel VH

Well, it’s been a little while since I’ve last posted here, and quite a bit has happened. Unfortunately (or Fortunately, depending on how you think about it) this one I’m going to talk about right now is big enough to denote it’s own specific blog post.

I’ve talked a time or two about that experiment I’ve been working on for class. Well, last weekend we launched our payloads, and it was AWESOME! Basically to preserve the feeling of how the day went, I will tell the story in chronological fashion, beginning when I got up at 4AM to make the final preparations.

First thing’s first. I had to play the obligatory final countdown.

After that was taken care of, I checked over all the systems to make sure they were running properly before being placed in their flight box for the trip to Moses Lake.

After checking, and getting everything together, the sun was rising, and it was time for me to head across campus to the Earth and Space Sciences building.

Then we all packed into vans and drove over to Moses Lake. That was a mostly boring part, but here’s a picture of Mt. Rainier from the 520 Bridge.

Then magically we arrived there and started setting up everything. Here’s some shots of the antennas we will shortly be using to track and get data off the balloons. The two antennas in the first picture are for the two main telemetry packages that I won’t be using. The second shot shows the first two antennas again, and then two more. The one I used to get my data back was the tall, long one on the left.

Then all the groups had time to make sure their payloads were still in running order, and get last minute things prepped for launch. You can see my payload here by my eeePc and the radio receiver. I changed to a fresh set of batteries (because it had to be on for the ride over to preheat the ozone sensor), and tested to make sure I was getting signal from the transmitter.

Then we sealed up the box, after attaching the transmission antenna (rather than the dummy antenna I mentioned earlier). Here’s the payload laying on the flight line. The black sticks are sticking out of the bottom and the antenna is tied in the middle of them so that when it lands on the ground, the antenna will be off the ground and give better signal for an easier recovery.

All the while, another group of students and TAs are inflating the balloon.

Then all that’s left to do is countdown, and liftoff!

From that point on it was me manning the three radios for the two balloon’s main telemetry systems, and the one for my radio link as well. In this picture I’m looking at the people manning the antennas. I had a great team who kept all the antennas pointed exactly at the balloons to give me the best chance of pulling a clear signal down for everyone.

Here’s one of one of the gals positioning one of the antennas.

And here’s a closeup of the radio for my link, connected to my eeePc pulling down the data! Wooo RTTY!

Then it was in the hands of the recovery team. I wasn’t on it, so I don’t know exactly what happened, but then ended up finding one balloon (the one my payload was on), due in part to the great signal strength I was dumping out! The other part was the brilliant tracking skillz of all involved. Thanks guys!

Anyway, we came home, and I had dinner, then waited around for the recovery team to get back (about an hour and a half later than we did). That way I could get my pictures that night!

Wanna see them? I bet you do! You sure? Oh, alright… Here’s the link [LINK UNAVAILABLE] and here’s a preview!

ENJOY!

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Class Experiment Continued

Posted on 2009-05-28 by Nigel VH

Well, here’s another update on that class experiment I’m doing. I got to go into one of the labs yesterday and run thermal testing on my team’s experiment. Overall it went pretty well despite a few errors.

Through the process of thermal testing, we cycle the board from room temperature, to +50 C (122 F), down to -50 C (-58 F), back to +50 C, and then let it come down to room temperature. These temperature fluctuations are designed to make the board, components, and solder joins expand and contract as much as possible. This allows us to make sure we have really solid solder joints. Here’s a picture of a thermometer telling us that it’s freaking cold!

All the meanwhile, I had the radio I will be using to receive my data sitting on a table near the thermal test chamber, picking up the transmitted data from the experiment to make sure it actually runs the whole time. Here’s a picture of that with my laptop receiving data.

Unfortunately, the test did not go as flawlessly as I had hoped, which means it wasn’t flawless. There were some errors, and there were some things I realized we need to consider.

One of them was a software error that I accidentally put in. A while ago I realized that the software couldn’t handle a negative temperature reading. So I corrected the software, but the day of the testing I accidentally loaded the old version on the board, so as soon as the temperatures got negative, I could only read zeros from the on board temperature sensor.

Secondly, There was an error that happened somewhere around -40 C where the chip stopped transmitting data. After warming the chamber back up, the chip began transmitting again, but the run time clock had been reset. So we decided it had to be either the chip, or the power with issues. Upon inspection of the board, I had neglected to fully seat the chip in it’s socket. This was likely our issue there.

Third and most important was our ozone sensor stopped responding at approximately -15 C. This was half expected, as we knew the ozone sensor wasn’t rated that low, however, we’d like to be able to get data points while we’re up there, so we’re thinking about using some pocket hand warmers and strapping them around it to try and keep it warm.

Beyond that, everything seems to be working fine. My lithium battery charger broke the other day, so I’ve rigged one since I don’t have time to order one before launch this Saturday. It seems to be working pretty well, and I actually might make a faster and more permanent version as the replacement for the broken one, rather than buying one.

The last thing I’ve done is slow down the data rate on my radio link, as during testing the transmitter was in a large metal box which made receiving signals harder (like it would be if it was 50-150 miles away). The slowed data rate makes each individual tone last a little longer, and makes it easier to decode.

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