I managed to break the LCD on my HP r717 digital camera a while back, but couldn't find anything that excited me as a replacement, so have been doing without and borrowing my son's camera from time to time. That changed recently... my new camera is a Casio High Speed EXILIM model EX-FC100BK.

I've never been able to get the timing right to take photos of our rockets leaving the launch rails. I manage to get passable videos from time to time, and a lot of pictures of smoke trails... but WOW, the ability to take a burst of high-resolution still photos at a fast frame rate (some of which are even before the shutter release gets fully pressed!) completely and totally rocks my world!

I just put a few of the best frames I captured at Saturday's launch up on Flickr. Enjoy!

Thanks to my wife Karen's graphic design skills, and Keith's SVG-foo, the Altus Metrum group of projects now has a logo!

Today was the season opener for Tripoli Colorado at their launch site on the buffalo ranch near Hartsel, Colorado. After huge snowfalls along the front range of the mountains in the last few days, we were a little tentative about going, but it turned out to be nearly perfect flying conditions! There was apparently much less snow this week on the high plains west of the front range, and by this morning the snow had almost entirely disappeared, the skies were clear and blue, and the winds were calm except for a few gusty bursts in the afternoon. This launch site is really something special, at 8800 feet above mean sea level, in the middle of a huge area of wide-open short grass prairie. We love flying there, and today the drive to and from the launch site through the snow-covered Colorado Rockies was just beautiful!

Son Robert and I flew three rockets today, including his LOC/Precision Lil Nuke with added payload section on an Aerotech G54W-M reload, and our Polecat Aerospace 5.5 inch Goblin kit on one of the relatively new Aerotech I245G-M "Mojave Green" green-flame reloads. But by far the highlight of the day was flying my Giant Leap Vertical Assault on a Cesaroni J335 red-flame reload... with serial number 1 of TeleMetrum on board collecting our first-ever flight data!

From the ground, it looked like a textbook perfect dual-deploy flight, with a small drogue chute out at apogee around 4000 feet above ground, and the main chute deploying at 700 feet above ground for a beautiful, soft landing only a couple minutes walk from the launch rail.

The ejection events were controlled by a PerfectFlite MiniAlt/WD. The data recovered from it shows a big negative spike in the altitude right at apogee, coincident with firing of the apogee deployment charge. I have to assume this means the aft bulkhead on the avionics bay in the reconstructed coupler section isn't sealing well, and some pressure from the apogee deployment charge leaked in to the avionics bay "fooling" the altimeter into thinking the altitude was lower for a sample or two. Clearly, that needs to get fixed before that airframe flies again.

Further evidence that we had a mighty kick from the apogee ejection charge was discovered when we went to clean the motor casing. The Cesaroni reloads are packaged in a plastic liner tube that slides into the reusable aluminum case. When we pulled the spent reload out of the case, it was significantly shorter than when it was loaded, suggesting that the ejection charge forced the forward closure on the reload backwards compressing the heat-softened plastic. This could be evidence that the reconstructed coupler was slow to separate from the booster airframe due to excessive friction?

The flight data recovered from the TeleMetrum board looks great until apogee, when the data collection stopped. Since I flew firmware that was compiled and flashed on the flight line from Keith's latest git commit as of this morning, it's entirely possible that there was a software bug that caused data collection to terminate at apogee. We'll investigate that. But I personally think what actually happened is that we experienced a temporary short in the power supply at the time the apogee ejection charge fired. On extraction of the electronics sled from the avionics bay this evening, I noticed that one of the mounting screws has gone missing. If it wasn't snug enough, and vibrated loose during flight, it could have been torn loose at the time of the ejection event and shorted something as it rattled around in the avionics bay. The screw is now just missing, but may have fallen out when we were extracting data on the flight line just after the flight without being noticed at the time. So I'm not inclined to worry much about this, at least until we can get some more flight data!

Keith post-processed the raw flight data and presented me with a plot showing two traces, acceleration and barometric altitude. The data from the accelerometer closely matches the published data for the motor we flew, which is a really cool result, and my 10-year-old son enjoyed figuring out why the rocket showed negative acceleration after the motor burn out but was still climbing. (See, there really is some science education hidden in the fun!)

All in all, we had a great time, and it's totally cool to have data from a first flight of TeleMetrum! Can't wait to fly it again!

Last night, I stayed up late reworking the avionics bay in my Giant Leap Vertical Assault kit. This is the rocket I set my personal best altitude to date of 14,141 feet above ground level with. The Missile Works RRC2 mini will move to a lesser airframe to keep it below 10k feet AGL since it's an early unit with the supposedly-buggy early firmware. In its place, I've mounted a PerfectFlite MiniAlt/WD to handle primary deployment duties... and serial number 1 of TeleMetrum!

Meanwhile, Keith has completely rewritten the guts of the firmware in the last few days to eliminate FreeRTOS since it turns out to just be too heavy for our needs on this project. My board is now running a snapshot of his latest work, and in bench testing I've confirmed that it can do launch detect, log sensor data until the non-volatile memory chip is full, and dump the raw data over USB for analysis after a flight.

Weather has been an issue in Colorado recently, but as soon as we get a decent launch day (maybe as early as this weekend?), I'm looking forward to flying this rocket on one or all of the Cesaroni I205, I540, and J285 currently in my box to get some initial flight data recorded. Keep your fingers crossed for me that the storm front headed towards us clears out by the weekend!

Keith and I have been plugging away for the last couple weeks turning on and testing the various bits of TeleMetrum, and I can now very happily report that we have all the hardware working! Amazingly, we got almost everything right in the hardware design. Only two things need to be changed.

We need to be able to control the chip select line on the the SPI non-volatile memory chip, which means we need one more GPIO line to it from the processor. To free up a line, we gave up the ability to put the accelerometer in to self test mode. Two trace cuts and two jumpers to the current board implement this change.

The last thing we got working just this evening was the ability to sense the presence of an ejection charge igniter. We need another resistor in each of the two sense circuits to form a voltage divider so that we don't overload the ADC input. Not sure how we missed that in our many design reviews! Oh well. To ensure robust ignition of the electric matches we prefer to use for ejection charges, we charge a 1000uF cap to a voltage higher than our ADC inputs can handle. Fixing this problem on the current boards requires changing the values of two resistors, then tacking extra resistor to one end of each of the existing ones and then wiring the other ends of the new resistors to ground. Since the resistors in question are all 0402 surface mount parts, this is a royal pain... but with my finest dental-pick soldering iron tip, and working under the inspection microscope, it is indeed possible.

Alternatively, if the ability to sense igniter continuity isn't important, just leaving off R14 and R15 at least prevents the 3.3V processor from going whacko due to having 5V applied to two ADC inputs!

I'm really impressed at how well these first two boards reflow soldered in the electric skillet in my basement came out. Getting the right amount of solder paste on the board is something I'm likely to get better at with practice, but so far we've only had a few (very obvious during inspection) shorts to clean up, and a couple poorly soldered pins. All in all, I couldn't be happier with how this has gone... and I'm really looking forward to flying one of these boards sometime soon as an auxiliarly payload to gather some initial flight data!

After a long hiatus for various reasons, I finally had the chance to try my hand at loading a TeleMetrum board today!

Sadly, I wasn't able to completely load any boards, because I somehow ended up with the wrong Digi-Key part numbers for 4 capacitors, one of which is a critical value. I placed an order for the missing parts and a few other bits we'll need eventually, hopefully they'll be here in a couple days and I can try to load a board with all the parts.

Instead, what I did today was a a partial load of a board with the goal of testing the various power supplies. Seemed like a good idea, since I've had my share of odd problems with power supplies in the past. This also gave me a chance to try out my solder paste stencil, get some experience hand-placing the tiny 0402 passive parts, and an excuse to see if I could hit the solder reflow temperature profile adequately with my electric cooking skillet and IR non-contact thermometer.

The good news is that it all worked right the first time! We're successfully charging a LiPo battery from USB power, and successfully making 3.3 volts for the electronics from that. The resistor divider designed to allow the LiPo battery voltage to be sampled by the CPU's analog to digital converter is also working fine.

A few observations are in order, however.

Getting the right amount of solder paste down on the board requires some finesse with the spreading blade and the stencil. I think the paste was a bit heavy around the CC1111 footprint, as I ended up with some bridged pads. Since I didn't load the actual CPU part, it could just be that not having something real there to wick up some solder meant there was enough to form the bridges. Don't know. The amount of solder on the ground pad in the middle of the chip looks good, though!

The 0603 sized LED in the power supply circuit was the only part that didn't self-align correctly. I may have had it a bit too far to one side. The pads on the part have notches in the end, and it looks like one side of each is more or less centered, so I think surface tension did the best it could with what I gave it to work with. The LED soldered ok, isn't shorting to anything else, and clearly works fine... but I'd be happier if it were aligned better.

Found and fixed a solder bridge between two pins on the surface-mount USB connector before first application of power. Could be further data that the paste layer was a bit too thick. On the other hand, I had to wiggle the connector around a bit to get it aligned correctly, so I may have smudged the paste into a bridge while doing that.

I also note that there's some visible flux left on the surface of the solder, particularly on big paste areas like the feet of the USB connector. I suspect this means I didn't dwell long enough at either or both of the preheat or ultimate reflow temperatures. Since all the parts clearly soldered adequately to function, I'm still pretty happy... but since the rockets we fly experience violent accelerations during boost, this is something I'll play with on future reflows.

All in all, a great way to spend an afternoon, and a big step forward for the TeleMetrum project!

People keep asking me about the beard thing... Here's my take on what happened and why.

Just before I left for LCA 2009, my wife offered to send along one of the limited edition prints of her award-winning waterfall photograph. She knew from prior years that the LCA organizers often host an auction or raffle to raise money for some worthy charity at the conference banquet. Since the photo was taken at Milford Sound on the way to last year's LCA in Melbourne, there was a connection between the photo and LCA. We had no idea what this year's charity might be, nor did we anticipate that her photo would become the centerpiece of the evening's fund-raising activities.

The charity selected this year was an organization that is trying to save the Tasmanian Devil from extinction. Professor Hamish McCallum, the chief scientist with the program, gave a talk after dinner and before the auction began. The native population is suffering from a fatal facial tumor disease that results in horrible lesions, and is likely to kill off all the Devils within a decade or three. My family and I all have a strong love of nature, and Karen and I had the pleasure of touring Tasmania after LCA 2003 in Perth, so this seemed like a great charity to raise money for with her photo.

As often happens at LCA, the auction and related fund-raising activities got complicated. This year, the photo alone was bid up to $2500 (which was very cool!), before people started offering things for higher bids. For years, going maybe as far back as Perth, I've been cajoled about shaving my beard if the bidding hit some level, and have always said no. This year, someone offered $5000 if I would shave my beard, and again I said no. Much later, after more cajoling and many counter offers, when the bids and various matching offers had us approaching $20,000 in total donation to the charity, I relented and announced that if we hit a total of $25,000 going to the charity I would consent to a shave. The resulting frenzy, including the suggestion that if it went high enough Linus should do the shaving, and the formation of a bidding consortium that kept raising more money and bidding against itself, was completely unexpected! Others have tried to capture details of the insanity, but the bottom line is that by the end of the evening, the total had blown way past anything we could have imagined, and by the end of the conference the total going to the charity was on the order of $40,000!

Why did I agree to let Linus shave my beard? To be honest, I'm not entirely certain. I only had one beer that evening, so I can't blame intoxication. The fact that it would yield a worthy charity something over 10 times what my wife's photo alone had drawn as a maximum bid seemed significant to me. In hindsight, I also think I was at least a little bit curious to see what my face looked like after having a beard since sometime around September of 1982! In any case, I made the offer, insane amounts of money were raised, and on the last day of the conference, over the lunch hour, Linus took trimmers in hand and removed my beard in front of an audience.

The reactions have been completely overwhelming. A local TV station and a local newspaper in Hobart were both there and ran stories. The ripple of mentions in the blogosphere was and is just astounding. There's even a silly Shaving Bdale game created overnight by the "Mad Scientists" at Secret Lab! And from all over the globe, people I do and don't know have been sending emails and finding me on IRC to plead with me to grow my beard again! Right after the shave, my good friend Keith Packard said "Bdale, grow it back!". Before I left Hobart, my wife emailed saying she and the kids hoped I wasn't waiting until I got home to start. Joey Hess blogged a hairy tale about how I'd scarred the minds of young Debian developers. The leader of Debian-RS sent word by email that the group all hoped I would re-grow my beard. And on and on and on... I'm really not used to being the center of so much attention!

Being suddenly without beard felt weird in lots of silly little ways. I was hyper-sensitive to drafts. The feel of cold beverages hitting my upper lip was downright strange. And I kept wanting to scratch what wasn't there! After making faces at myself in the mirror for a while, I decided I really wasn't happy, and do prefer being bearded. So I haven't shaved since Saturday morning in Hobart, and am pretty scruffy looking. My wife said today that I'm "already starting to look like Bdale again".

At the current growth rate, I have high hopes of having at least some facial dignity back by the time I speak at FOSDEM. And no, I won't be shaving my beard off again any time soon...

My talk about how I combine open source and rockets at LCA 2009 that included my first public presentation of the TeleMetrum design was well received, and I was invited to repeat it during Open Day on Saturday.

Now that I'm home again, I need to get some parts loaded on a board so we can start testing!

Yesterday, I closed Debian bug #211765 regarding material under the GLX Public License violating the DFSG.

That's two less open bugs tagged lenny-ignore!

I just moved my blog from blosxom to ikiwiki. Slowly, but surely, my web-related infrastructure for gag.com and related sites is all moving to ikiwiki+git...

I shoved in a rewrite rule to map the old top-level URL to the new one, and ensured that my rss feed will only contain new posts. However, all the "permanent" article paths changed. Oh well. I'm much happier now!