This afternoon, a box arrived from Advanced Circuits, containing 108 fully assembled TeleDongle boards!

This is not only the first "intended for sale" build of hardware from the Altus Metrum family of projects, it's also the first time that I've ever sent out one of my board designs for someone else to assemble. I therefore approached the turn-on and test of the first board out of the box with more than a little trepidation... fortunately, for no reason!

I'm immensely pleased to report that TeleDongle serial number 100 turned on and works entirely as expected!

I celebrated by packaging it in a cool little Hammond translucent blue plastic box with a USB cable, yielding the first prototype of a fully packaged TeleDongle board such as we anticipate selling for use receiving data from rockets carrying TeleMetrum boards.

We also intend to sell these boards as-is (flashed with default firmware and measured oscillator cal value) to folks who'd like a robust wireless link for their next microcontroller project, whether rocket-related or not. I will, of course, post something here when we're ready to start taking orders.

Now we just need the weather to cooperate long enough to log more test flights of TeleMetrum. The new version looks great so far, but I want a few more flights before I'll be confident enough to place an order with our assembler for a run of those too... Stay tuned!

On Saturday, I joined The Albuquerque Rocket Society monthly launch in Rio Rancho, NM. A friend, Mike, who lives in the area joined me for the launch. While the morning started off clear and calm, if a bit cold... the wind came up hard and we had to call it quits before lunch. But before the wind "blew us away", I managed to get one flight in. And it was an absolutely perfect test of one of my brand-new TeleMetrum v0.2 boards!

My cut-down Hawk Mountain "Raptor" kit, renamed "G-Spot" last October during my quest to exceed 50 g acceleration, was loaded with TeleMetrum serial number 51... and launched on a Cesaroni 229H255WT-14A motor.

The ascent was beautiful! I've put a few photos of the rocket leaving the launch rail up on flickr. However, despite a clear sky, we quickly lost sight of it! I managed to spot a bit of the smoke trail from the delay grain as the rocket approached apogee, but that was it! None of us at the launch saw anything after apogee!

After losing sight of the rocket, I turned my attention to my computer, where we were receiving a solid telemetry stream. It quickly became apparent that the rocket was descending normally under chute. As it got closer to the ground, I started calling out elevation, azimuth, and distance numbers, but still nobody could spot the rocket. As expected, we lost the RF link once the rocket reached the ground.

As various folks on the flight line wished me luck finding my rocket, I put the last reported GPS position into my hand-held receiver. Staring at the map display, Mike and I realized the rocket was far down range, near one of the roads into the site. We jumped into my vehicle and drove down the road to the point closest to the rocket's reported position. We then walked to where the GPS receiver said the rocket should be...

And found the rocket within about 20 feet! That was well within the window of position uncertainty my hand-held GPS was reporting at the time. Things just don't get much better than that! We picked up the rocket, and returned to the flight line only a few minutes after leaving it. After dumping the data from the board's on-board memory, I quickly generated the usual plots, along with a kml file that can be viewed in Google Earth.

The rocket reached 1881 meters apogee, or around 6173 feet, and the maximum acceleration was 19.5 g. It touched down nearly 1.3 miles down range from the launch rail, in sage-brush desert. I honestly don't think I would have found the rocket without at least the radio beacon. It was hugely gratifying that the GPS worked and let me walk right up to the rocket! I could not have asked for a better test of the new electronics!

Later in the day, Keith flew a successful test of serial number 52 at a launch in Wilsonville, Oregon.

We're very happy with these results! Weather permitting, I hope to get more test flights in next weekend at Hudson Ranch. Stay tuned!

Today, the panels of bare circuit boards, the paste stencil, and the last parts I need (the Venus GPS modules) to hand assemble first-article prototypes of TeleMetrum v0.2 all arrived!

The parts for the first three prototypes are staged and ready to load, so my next step is to go use my CNC mill to rip up one of the panels into individual boards, then make up a fixture for the stencil. Meanwhile, the solder paste is out of the shop fridge warming up...

For my friends in Colorado, this means I will not try to attend the NCR annual meeting this weekend. It's about a 6 hour round-trip drive from my house to Ault, and getting boards loaded and tested before I leave for New Zealand where Keith and I are scheduled to give a talk at LCA about our work takes priority!

Some quotes are in for professional SMT assembly of TeleMetrum v0.2, and I've had to reset my expectations. The shop I thought would be my first choice came in with a quote much higher than I expected. Another shop we've heard good things about gave us a much more reasonable quote, but can't get any made before LCA. So...

This morning, I ordered some bare circuit boards and a paste stencil from the places I used quite successfully for v0.1. With any luck, they'll be in my hands in time to load a few boards before leaving for LCA.

If all goes well, we'll put a set out for professional fab sometime later.

I just sent a data package representing TeleMetrum version 0.2 out for an assembly quote. Hope to have first article boards in hand before heading to linux.conf.au 2010 where Keith and I are scheduled to give a talk about the project.

Keith and I have been pretty quiet about TeleMetrum for a while... but that doesn't mean we've been idle!

In recent weeks, I've built up several more flight units and two more ground station boards, as noted in my production log. We're both trusting rockets solely to our boards and Keith's firmware at this point. In fact, we've accumulated a significant number of succesful flights, including a cool drag-race between 4" airframes at NCR Oktoberfest where we both put brand-new, nearly identical rockets fully at risk flying only TeleMetrum boards, and a flight by Keith the same weekend on a full-K Loki K350W moon-burner in which he set a new personal altitude record! I've also flown a board with 100-g accelerometer installed successfully in a flight that peaked at 52.8 g!

We're now hard at work on a "next version" of the hardware, incorporating everything we've learned so far. There are a number of significant changes planned:

• Fully integrated, on-board GPS receiver and patch antenna, with support for off-board amplified antennas when airframe geometry or materials demand it.

• A change in the design of the circuit for firing e-matches to ignite ejection charges that will improve mechanical reliability, plus explicit support for using a separate pyro battery if desired.

• Inclusion of a "companion board interface" that we envision using for a pyro channel expansion board to support staging and air starts, among other things.

• Dramatic increase in the capacity of the on-board data logging memory.

• Changes in connector series to eliminate our dependency on expensive crimping tools for making cables.

To make all this fit, I'm stretching the board an extra 1/4 inch to a total outline of 1 by 2.75 inches. We're also moving all the connectors, the GPS patch antenna, and the beeper to the "back side" of the PC board. This is a win on several levels... it will allow us to have silk-screen labels for the connectors, will help protect the baro sensor from sunlight and the various surface mount parts from physical damage during rocket prep, and opens up more board surface area for component placement and routing on the "top side" of the board. In practice, this means that boards will be mounted on standoffs with all the active components facing "down" and the connectors facing "up."

Before we'll be ready to build some of these, we need to get in some more flights to test the various changes we're making. In particular, the change in ejection charge circuit, and the GPS receiver chip and antenna choices we're now favoring. Unfortunately, Keith and I are now both into the time of year where launch opportunities come less frequently, even before we consider the weather.

Meanwhile, Keith's firmware and ground station software are now doing nearly everything we've envisioned wanting from this project. It seems entirely likely that he'll be ready to declare "version 1.0" soon after we obtain and verify the functionality of our next version of the hardware...

In the meantime, our friends at Woot have posted a really funny video combining material from a couple launches this summer of my 10-inch Goblin, on one of which we flew some of their screaming flying monkey dolls... Enjoy!

In preparation for several upcoming high power rocket launches, I've spent some time over the last two weeks building up several more TeleMetrum boards. Five new ones, in fact, serial numbers 7 through 11. The first four are fully-loaded normal boards, the last one has a 100 gee accelerometer installed instead of the normal 50 gee part.

While I haven't yet tested 100% of the functionality on all five, I'm definitely getting better at loading and reflow soldering these boards. I found exactly one soldering defect, a bridge between two pins on the cc1111 noticed during initial visual inspection which was easily removed, and all five flashed and passed initial tests on the first try!

I also retrieved one of the OLPC XO machines from my son and loaded it up with Debian for the XO, then upgraded it to unstable so that I can use it as a ground station for receiving telemetry. Having a small machine with long battery life and a screen that is readable in direct sunlight should be a huge win!

Now that I care about having working AltOS bits on more than one machine, I took some time today and created a Debian package. In the process, as I stumbled over various issues, Keith was quick to jump in and help... as were fellow Debian developers on IRC. We now have a "lintian clean" package that's easily maintainable from our shared git repository, and yes, we even have man pages for all the utilities!

A special note for folks near Colorado. Weather permitting, this Sunday morning the 23rd of August, I'm planning to "drag race" my big Goblin airframe against Jason Chamberlin's similarly-sized Polecat Fat Man on long-burning Aerotech M650W motors at Chili Blaster. Even for those of us who fly high power model rockets every chance we get, a drag-race between 10-inch airframes on long-burning M motors is a special event. If you've never seen rockets like this fly, and/or would like to see a TeleMetrum board in action, this would be a great time to come hang out with us!

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!