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git://keithp.com/git/hw/fireworks

git://keithp.com/git/hw/keithp

• Add mounting holes. Not having any way to mount the boards means that they re flopping around inside the cabinet. We ll probably find a way to tie them down somehow, but a couple of holes in the boards would have made that really easy.
• Increase the gap between the pin pads and the ground plane. The narrow space provided ample opportunity for solder bridges. I ve increased that spacing in the git repository version of the boards.
• Used a variable resistor for LED current control. With a fixed value, it s very difficult to adjust the relative brightness of the LEDs. Even though we used LEDs from the same series, the different colors have different apparent brightness.
• Used surface mount passives. We had bought through-hole parts when the plan was to build these on a breadboard, but soldering through-hole parts onto the board is more work than using surface mount parts. 0805 (or even 1206) parts are plenty large to solder by hand and are faster to deal with than having to fold leads, insert them into holes, flip the boards over, solder them down and trim the leads.
• Perhaps we went a bit overboard on this project

• The gEDA tools aren t that hard to use. Constructing the circuit board really was a simple matter of painting with copper. If you can drive inkscape, you can make circuit boards.
• Advanced Circuits bare-bones PCB service. It was really cool to upload the output files from gEDA and have actual boards arrive in the mail a couple of days later.
• Building the boards. I really didn t expect all of the components to just fit in the boards; I figured I d mess up the footprints or drill sizes and end up kludging something onto the boards. Bdale did catch a small drill size on the LED driver pins, which I bumped up a bit, but other than that, all of the parts slipped in and soldered easily. Each board took about 10 minutes to put together.

It s a great feeling to have earned the trust of your friends and peers.

1. It targets the latest version of 32-bit ARM CPUs (v7) and makes better use of the hardware, for better performance. Compare targetting i686 instead of i386, for example. We ll still support the older armel port for the foreseeable future for users with older hardware that can t run armhf.
2. More importantly: we are standardising on the ABI / compiler options / hardware support for future users.

• With the historical issues around the plethora of ARM ABIs in the wild, multi-arch will allow us to potentially support multiple ABIs cleanly on one system. That allows users to have (for example) an up-to-date system that makes the most of their current hardware, yet also run legacy programs that might use an older ABI. There s also a new 64-bit architecture coming (ARMv8) which will run older 32-bit software; again, multi-arch makes mixed installation of old and new software reasonable.
• ARM has traditionally been a common target for cross-compilation, and I d expect that to remain the case for a long time to come yet. For a lot of embedded developers, using a big fast i386/amd64 machine to compile is much faster than using a limited-power small ARM CPU. However, setting up sane cross-compilation environments has long been a bugbear for developers. Getting the toolchain and all the cross-architecture libraries to work together correctly can be like black magic. This is potentially the killer app for multi-arch: simply install the libraries for the target architecture directly on your development machine. Install a simple cross-gcc package and (maybe) qemu, and you re all set.

This is potentially the killer app for multi-arch: simply install the libraries for the target architecture [ ], install a simple cross-gcc package [ ] and you re all set.

We are forever short of enough people to do the work that we re trying to do.

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• Change telemetry to be encoded in multiple 32-byte packets. This enables support for TeleMini and other devices without requiring further updates to the TeleDongle firmware. Previous versions of the firmware used a large monolithic telemetry packet 95 bytes long. The old single-packet format included all of the rapidly updating data coming from the on-board sensors, along with slowly changing GPS data and never-changing configuration data. Not only were the packets large (reducing the reliability of reception), they were also device-specific, encoding precisely the set of information available in TeleMetrum. The new telemetry system uses mulitple different formatted telemetry packets, all 32 bytes in length, transmitting rapidly changing data often and other data more slowly. This should improve reception, but more importantly, allows for different devices to send different sets of data. Within the TeleDongle, this change was implemented by removing all of the telemetry decoding logic from the embedded device and moving it to the AltosUI java code running on the host. This means that the TeleDongle can now receive arbitrary telemetry packets without having new firmware installed.
• Support operation of TeleMetrum with the antenna pointing aft. Previous firmware versions required the antenna to be pointing upwards, now there is a configuration option allowing the antenna to point aft, to aid installation in some airframes. A TeleMetrum user, DK Duncan, changed the firmware on his board to flip the accelerometer ADC values around. This produced something that worked on the ground, so he went and flew it. And it just worked. I added this as a configuration option, including all of the Java code to change it. Nice that any Altus Metrum user can try things like this out and then have them get added in the next version of the software.
• Ability to disable telemetry. For airframes where an antenna just isn t possible, or where radio transmissions might cause trouble with other electronics, there s a configuration option to disable all telemetry. Note that the board will still enable the radio link in idle mode. Terry Lee is taking a TeleMetrum board for a ride during LDRS this year, but with TeleMetrum mixed in with a pile of other electronics, he didn t want us transmitting during flight and causing potential RFI issues with other boards in the air frame. Instead of building a custom version of the firmware, we just made this a configurable mode.
• Arbitrary frequency selection. The radios in Altus Metrum devices can be programmed to a wide range of frequencies, so instead of limiting devices to 10 pre-selected channels , the new firmware allows the user to choose any frequency in the 70cm band. Note that the RF matching circuit on the boards is tuned for around 435MHz, so frequencies far from that may reduce the available range.
• Kalman-filter based flight-tracking. The model-based sensor fusion approach of a Kalman filter means that AltOS now computes apogee much more accurately than before, generally within a fraction of a second. In addition, this approach allows the baro-only TeleMini device to correctly identify Mach transitions, avoiding the error-prone selection of a Mach delay. Developing this feature made extensive use of the simulator which runs the flight management code using sensor data captured on previous flights. Somehow, we ve managed to collect log data from over 100 flights; replaying them on the ground means that even before the first flight with the new firmware, we were confident that it would work.

• Add main/apogee voltage graphs to the data plot. This provides a visual indication if the igniters failed before being fired.
• Scan for altimeter devices by watching the defined telemetry frequencies. This avoids the problem of remembering what frequency a device was configured to use, which is especially important with TeleMini which does not include a USB connection.
• Monitor altimeter state in Idle mode. This provides much of the information presented in the Pad dialog from the Monitor Flight command, monitoring the igniters, battery and GPS status withing requiring the flight computer to be armed and ready for flight.
• Pre-load map images from home. For those launch sites which don t provide free Wi-Fi, this allows you to download the necessary satellite images given the location of the launch site. A list of known launch sites is maintained at altusmetrum.org which AltosUI downloads to populate a menu; if you ve got a launch site not on that list, please send the name of it, latitude and longitude along with a link to the web site of the controlling club to the altusmetrum mailing list.
• Flight statistics are now displayed in the Graph data window. These include max height/speed/accel, average descent rates and a few other bits of information. The Graph Data window can now be reached from the Landed tab in the Monitor Flight window so you can immediately see the results of a flight.

import os
import glob
import itertools
import collections
from dateutil.parser import parse
from debian.changelog import Changelog
data = collections.defaultdict(set)
for package in glob.glob('/apt/*'):
    if os.path.islink(package):
        continue # Consider source packages only
    try:
        changelog = Changelog(open('%s/debian/changelog' % package))
    except:
        continue # Ignore invalid changelogs
    for entry in changelog:
        try:
            data[entry.author].add(parse(entry.date).strftime('%z'))
        except ValueError:
            pass # Ignore invalid dates
fn = lambda x: len(x[1])
top = sorted(data.items(), key=fn, reverse=True)
for k, g in itertools.groupby(top, key=fn):
    print "\n%d timezone(s):" % k
    for author, timezones in sorted(g):
        print " * %s (%s)" % (
            author.encode('utf8', 'ignore'),
            ', '.join(sorted(timezones, reverse=True)),
        )

14 timezone(s):
 * Bdale Garbee <bdale@gag.com> (-0800, -0700, -0600, -0500, -0400, -0300,
   +1300, +1100, +1030, +0900, +0300, +0200, +0100, +0000)
12 timezone(s):
 * Joey Hess <joeyh@debian.org> (-1000, -0900, -0800, -0700, -0500, -0400,
   -0300, -0200, +0300, +0200, +0100, +0000)
11 timezone(s):
 * Paul Wise <pabs@debian.org> (-0400, -0300, +1300, +1100, +1000, +0930,
   +0900, +0800, +0200, +0100, +0000)
9 timezone(s):
 * Barak A. Pearlmutter <bap@debian.org> (-0700, -0600, -0500, -0400, +0500,
   +0300, +0200, +0100, +0000)
 * Martin Michlmayr <tbm@cyrius.com> (-1000, -0700, -0300, +1100, +1000,
   +0300, +0200, +0100, +0000)
 * Martin Pitt <mpitt@debian.org> (-0800, -0700, -0600, -0500, -0400, +0300,
   +0200, +0100, +0000)
 * Sam Hocevar (Debian packages) <sam+deb@zoy.org> (-0700, -0500, -0400, -0300,
   +0930, +0300, +0200, +0100, +0000)

Photograph taken by Julia Palandri

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• Identify cruft that can be removed from your Debian system
• Remove automatically installed packages

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• Mac OS X graphing repaired. The 0.9 release was missing a file required to support the graphing feature (jcommon.jar). This has been added.
• Fixed multiple flight log downloading. Attempts to download more than one recorded flight log would fail in weird ways. The failures have been addressed and additional diagnostics are presented when things go wrong.
• You can see the AltOS version number in the Configure AltosUI dialog box now. This should make it easier to tell what you ve got installed.
• Post-flight graphing tool. This lets you explore the behaviour of your rocket after flight with a scroll-able and zoom-able chart showing the altitude, speed and acceleration of the airframe along with events recorded by the flight computer. You can export graphs to PNG files, or print them directly.

• Post-flight graphing tool. This lets you explore the behaviour of your rocket after flight with a scroll-able and zoom-able chart showing the altitude, speed and acceleration of the airframe along with events recorded by the flight computer. You can export graphs to PNG files, or print them directly.

• Real-time moving map which overlays the in-progress flight on satellite imagery fetched from Google Maps. This lets you see in pictures where your rocket has landed, allowing you to plan recovery activities more accurately.

• Wireless recovery system testing. Prep your rocket for flight and test fire the deployment charges to make sure things work as expected. All without threading wires through holes in your airframe.
• Optimized flight status displays. Each flight state now has it s own custom tab in the flight monitoring window so you can focus on the most important details. Pre-flight, the system shows a set of red/green status indicators for battery voltage, apogee/main igniter continutity and GPS reception. Wait until they re all green and your rocket is ready for flight. There are also tabs for ascent, descent and landing along with the original tabular view of the data.
• Monitor multiple flights simultaneously. If you have more than one TeleDongle, you can monitor a flight with each one on the same computer.
• Automatic flight monitoring at startup. Plug TeleDongle into the machine before starting AltosUI and it will automatically connect to it and prepare to monitor a flight.
• Exports Google Earth flight tracks. Using the Keyhole Markup Language (.kml) file format, this provides a 3D view of your rocket flight through the Google Earth program.

• Receive and log telemetry from a connected TeleDongle device. All data received is saved to log files named with the current date and the connected rocket serial and flight numbers. There is no mode in which telemetry data will not be saved.
• Download logged data from TeleMetrum devices, either through a direct USB connection or over the air through a TeleDongle device.
• Configure a TeleMetrum device, setting the radio channel, callsign, apogee delay and main deploy height. This can be done through either a USB connection or over a radio link via a TeleDongle device.
• Replay a flight in real-time. This takes a saved telemetry log or eeprom download and replays it through the user interface so you can relive your favorite rocket flights.
• Reprogram Altus Metrum devices. Using an Altus Metrum device connected via USB, another Altus Metrum device can be reprogrammed using the supplied programming cable between the two devices.
• Export Flight data to a comma-separated-values file. This takes either telemetry or on-board flight data and generates data suitable for use in external applications. All data is exported using standard units so that no device-specific knowledge is needed to handle the data.
• Speak to you during the flight. Instead of spending the flight hunched over your laptop looking at the screen, enjoy the view while the computer tells you what s going on up there. During ascent, you hear the current flight state and altitude information. During descent, you get azimuth, elevation and range information to try and help you find your rocket in the air. Once on the ground, the direction and distance are reported.

• Anthony Towns wrote both the new data graphing interface and the moving map display.
• Bob Finch helped clean up our documentation, and provided flight testing for the firmware updates.

• A Kalman-filter based approach to apogee detection using more than just the baro sensor, so that we can safely control apogee ejection on flights to altitudes beyond the range of our baro sensor alone. Unlike the other items on the list, this will be a significant change to the in-rocket TeleMetrum firmware. It may therefore be a while before this becomes part of a stable firmware release.
• Motor characterization. Because TeleMetrum contains a high-resolution, high-frequency accelerometer, it is possible to take the data from that and compute an accurate thrust curve for the motor.
• Comprehensive PDF and/or HTML -based flight report. Construct a complete report of the flight suitable for publication on the web that includes graphs of the flight and details about motor performance etc.
• Publish flight data to the Altus Metrum web site. This will allow you to share your flight data with others, and let you download flights published by others.