Latest posts for tag openmoko

I am trying to play a bit with Vala on the FreeRunner.

The freesmartphone.org stack on the OpenMoko is heavily based on DBus. Using DBus from Vala is rather simple, if mostly undocumented: you get a few examples in the Vala wiki and you make do with those.

All works fine with simple methods. But what with providing callbacks to signals that have complex nested structures in their signatures, like aa{sv}? You try, and then if you don't get the method signature right, the signal is just silently not delivered because it does not match the method signature.

So this is how to provide a callback to org.freesmartphone.Usage.ResourceChanged, with signature sba{sv}:

public void on_resourcechanged(dynamic DBus.Object pos,
                   string name,
                   bool state,
                   HashTable<string, Value?> attributes)
{
    stderr.printf("Resource %s changed\n", name);
}

And this is how to provide a callback to org.freesmartphone.GPS.UBX.DebugPacket, with signature siaa{sv}:

protected void on_ubxdebug_packet(dynamic DBus.Object ubx, string clid, int length,
        HashTable<string, Value?>[] wrongdata)
{
    stderr.printf("Received UBX debug packet");

    // Ugly ugly work-around
    PtrArray< HashTable<string, Value?> >* data = (PtrArray< HashTable<string, Value?> >)wrongdata;

    stderr.printf("%u elements received", data->len);
}

What is happening here is that the only method signature that I found matching the dbus signature is this one. However, the unmarshaller for some reason gets it wrong, and passes a PtrArray instead of a HashTable array. So you need to cast it back to what you've actually been passed.

Figuring all this out took several long hours and was definitely not fun.

The FreeRunner has a headset which includes a microphone and a button. When doing OpenStreetMap mapping, it would be very useful to be able to keep tangogps on the display and be able to mark waypoints using the headset button, and to record an audio track using the headset microphone.

In this way, I can use tangogps to see where I need to go, where it's already mapped and where it isn't, and then I can use the headset to mark waypoints corresponding to the audio track, so that later I can take advantage of JOSM's audio mapping features.

Enter audiomap:

$ audiomap --help
Usage: audiomap [options]

Create a GPX and audio trackFind the times in the wav file when there is clear
voice among the noise

Options:
  --version      show program's version number and exit
  -h, --help     show this help message and exit
  -v, --verbose  verbose mode
  -m, --monitor  only keep the GPS on and monitor satellite status
  -l, --levels   only show input levels

If called without parameters, or with -v which is suggested, it will:

1. Fix the mixer settings so that it can record from the headset and detect headset button presses.
2. Show a monitor of GPS satellite information until it gets a fix.
3. Synchronize the system time with the GPS time so that the timestamps of the files that are created afterwards are accurate.
4. Start recording a GPX track.
5. Start recording audio.
6. Record a GPX waypoint for every headset button press.

When you are done, you stop audiomap with ^C and it will properly close the .wav file, close the tags in the GPX waypoint and track files and restore the mixer settings.

You can plug the headset out and record using the handset microphone, but then you will not be able to set waypoints until you plug the headset back in.

After you stop audiomap, you will have a track, waypoints and .wav file ready to be loaded in JOSM.

Big thanks go to Luca Capello for finding out how to detect headset button presses.

I was missing a simple command line tool that allows me to perform basic GPS queries in shellscripts.

Enter getgps:

# getgps --help
Usage: getgps [options]

Simple GPS query tool for the FSO stack

Options:
  --version          show program's version number and exit
  -h, --help         show this help message and exit
  -v, --verbose      verbose mode
  -q, --quiet        suppress normal output
  --fix              check if we have a fix
  -s, --sync-time    set system time from GPS time
  --info             get all GPS information
  --info-connection  get GPS connection information
  --info-fix         get GPS fix information
  --info-position    get GPS position information
  --info-accuracy    get GPS accuracy information
  --info-course      get GPS course information
  --info-time        get GPS time information
  --info-satellite   get GPS satellite information

So finally I can write little GPS-aware scripts:

if getgps --fix -q
then
    start_gps_aware_program
else
    start_gps_normal_program
fi

Or this.

I have it in my TODO list to implement taking waypoints when pressing the headset button of the openmoko, but that is not done yet.

In the meantime, I did some experiments with audio mapping, and since I did not manage to enter waypoints while recording them, I was looking for a way to make use of them anyway.

Enter findvoice:

$ ./findvoice  --help
Usage: findvoice [options] wavfile

Find the times in the wav file when there is clear voice among the noise

Options:
  --version             show program's version number and exit
  -h, --help            show this help message and exit
  -v, --verbose         verbose mode
  -p NUM, --percentile=NUM
            percentile to use to discriminate noise from voice
            (default: 90)
  -t, --timestamps      print timestamps instead of human readable information

You give it a wav file, and it will output a list of timestamps corresponding to where it things that you were talking clearly and near the FreeRunner / voice recorder instead of leaving the recorder dangling to pick up background noise.

Its algorithm is crude and improvised because I have no background whatsoever in audio processing, but it basically finds those parts of the audio file where the variance of the samples is above a given percentile: the higher the percentile, the less timestamps you get; the lower the percentile, the more likely it is that it picks a period of louder noise.

For example, you can automatically extract waypoints out of an audio file by using it together with Geocoding Unix timestamps:

./findvoice -t today.wav | ./gpxinterpolate today.gpx > today-waypoints.gpx

The timestamps it outputs are computed using the modification time of the .wav file: if your system clock was decently synchronised (which you can do with getgps), then the mtime of the wav is the time of the end of the recording, which gives the needed reference to compute timestamps that are absolute in time.

For example:

getgps --sync-time
arecord file.wav
^C
./findvoice -t file.wav | ./gpxinterpolate today.gpx > today-waypoints.gpx

Geocoding EXIF tags in JPEG images is fun, but there is more that can benefit from interpolating timestamps over a GPX track.

Enter gpxinterpolate:

$ ./gpxinterpolate --help
Usage: gpxinterpolate [options] gpxfile [gpxfile...]

Read one or more GPX files and a list of timestamps on standard input. Output
a GPX file with waypoints at the location of the GPX track at the given
timestamps.

Options:
  --version      show program's version number and exit
  -h, --help     show this help message and exit
  -v, --verbose  verbose mode

For example, you can create waypoints interpolating file modification times:

find . -printf "%Ts %p\n" | ./gpxinterpolate ~/tracks/*.gpx > myfiles.gpx

In case you wonder where you were when you modified or accessed a file, now you can find out.

The FreeRunner can record audio. It is nice to record audio: for example I can run the recording in background while I keep tangogps in the screen, and take audio notes about where I am while I am doing mapping for OpenStreetMap.

Here is the script that I put together to create geocoded audio notes:

#!/bin/sh

WORKDIR=~/rec
TMPINFO=`mktemp $WORKDIR/info.XXXXXXXX`

# Sync system time and get GPS info
echo "Synchronising system time..."
getgps --sync-time --info > $TMPINFO

# Compute an accurate basename for the files we generate
BASENAME=~/rec/rec-$(date +%Y-%m-%d-%H-%M-%S)
# Then give a proper name to the file with saved info
mv $TMPINFO $BASENAME.info

# Proper mixer settings for recording
echo "Recording..."
alsactl -f /usr/share/openmoko/scenarios/voip-handset.state restore
arecord -D hw -f cd -r 8000 -t wav $BASENAME.wav

echo "Done"

It works like this:

1. It synchronizes the system time from the GPS (if there is a fix) so that the timestamps on the wav files will be as accurate as possible.
2. It also gets all sort of information from the GPS and stores them into a file, should you want to inspect it later.
3. It records audio until it gets interrupted.

The file name of the files that it generates corresponds to the beginning of the recording. The mtime of the wav file obviously corresponds to the end of the recording. This can be used to later georeference the start and end point of the recording.

You can use this to check mixer levels and that you're actually getting any input:

arecord -D hw -f cd -r 8000 -t wav -V mono /dev/null

The getgps script is now described in its own post.

You may now want to experiment, in JOSM, with "Preferences / Audio settings / Modified times (time stamps) of audio files".

I got myself a FreeRunner. Here are some notes from the first few days:

Available operating systems

The FreeRunner comes with the Om 2007.2 distribution: it works for basic phone things, and it has an opkg package manager that you can use to install all sort of extra software. Only issue: the SMS application was rather unstable with my SIM card.

I then tried Om 2008.8, which is a major new redesign, partly based on Qtopia. It's definitely more advanced on how it looks, with smooth animations all around, but I did not manage to get the GSM part to work, because I did not manage to get it to ask for a PIN.

I then tried plain Qtopia and I got what looks and feels like a properly working mobile phone. The only issue that it has is that I did not manage to make it suspend, so battery life is much shorter than it could be. Apparently, this should improve as kernel 2.6.26 reaches the phone. I kept Qtopia installed in the phone flash as a "stable" phone system.

And finally, Debian. Debian is based on the freesmartphone.org software stack, which is an attempt to create a UI agnostic DBUS frontend to the hardware that supports multiple applications running on top of it. It is a young project, but it can already drive a mobile phone in a useful way. It has a demo interface that is basically a showcase of what is implemented in the DBUS frontend, but does most of the basic things you need from a mobile phone, including taking and making phone calls. And then it has Debian behind, all of it. I need to buy a bigger microsd card.

Tips and tricks

Flashing things

1. apt-get install dfu-util
2. Start the Freerunner bios/bootloader, by holding down Power and then pressing AUX (standard bootloader), or by holding down AUX and then pressing Power (factory, unbrickable, read only fail safe bootloader).
3. dfu-util -l shows you a list of devices it can access. If you see more than once, you need to specify in all dfu-util commands which one you want, using -d USBID. In my case, I have to always use dfu-util -d 0x1d50:0x5119
4. To flash the kernel: dfu-util -a kernel -R -D /path/to/uImage
5. To flash the root file system: dfu-util -a rootfs -R -D rootfs_filename.jffs2
6. To flash the bootloader: dfu-util -a u-boot -R -D uboot_filename.bin
7. To flash the u-boot configuration: dfu-util -a u-boot_env -D env.new

You can also download all of these things from the FreeRunner by using -U instead of -D.

Networking via USB

All of the distributions I tried, by default configure the USB as a gadget with ethernet over usb. You can form a lan with it using the cdc_ether module, and you will find your phone preconfigured as 192.168.0.202 expecting to find a gateway at 192.168.0.200.

I made myself this script to start and stop networking with the phone:

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#!/bin/sh

case "$1" in
    start)
        iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE -s 192.168.0.200/29
        ifconfig usb0 192.168.0.200 netmask 255.255.255.248
        /etc/init.d/dnsmasq start
        echo 1 > /proc/sys/net/ipv4/ip_forward
        ;;
    stop)
        echo 0 > /proc/sys/net/ipv4/ip_forward
        /etc/init.d/dnsmasq stop
        iptables -t nat -F POSTROUTING
        ifconfig usb0 down
        ;;
esac

Besides doing masquerading, it also brings up dnsmasq so that the phone can always find a DNS together with the router.

Another useful trick is to configure the phone to share the approx cache with the laptop:

deb http://192.168.0.200:9999/debian unstable main
deb http://192.168.0.200:9999/debian experimental main
deb http://pkg-fso.alioth.debian.org/debian unstable main

So yes, my laptop can now be turned into a phone charger with networking, DNS and apt cache services. I shall look into hooking that script into dbus to have it run automatically when the phone is plugged and unplugged.

Changing the ringtone in Debian

In case you don't like the default ringtone, this is how to change it:

1. vi /usr/share/python-support/fso-frameworkd/framework/subsystems/oeventd/receiver.py
2. look for def _play( self ):
3. change the codec in decoder = gst.element_factory_make, if needed. The list of available plugins is on the gstreamer website.
4. change the path in filesrc.set_property
5. /etc/init.d/fso-frameworkd restart and maybe /etc/init.d/zhone-session restart

Yes, the ringtone is currently hardcoded, but it does say it's a prototype after all. Or, if you prefer, it's fully configurable and the configuration can be found in /usr/share/python-support/fso-frameworkd.

Configuring the bootloader

You can connect to the u-boot bootloader via a serial terminal on /dev/ttyACM0. Type help and you will find that it can do a lot of things. The OpenMoko wiki has pages on the bootloader itself, its commands and the environment.

The environment is the configuration of the bootloader, similar somehow to /boot/grub/menu.lst. Unlike grub, you can edit the environment from within the bootloader and then save it using the saveenv command.

What I did:

1. A boot entry for Debian, with the kernel on an ext2 partition instead of fat: setenv menu_3 Boot from microSD (FAT+ext2): setenv bootargs \${bootargs_base} rootfstype=ext2 root=/dev/mmcblk0p2 rootdelay=5 \${mtdparts} ro\; mmcinit\; fatload mmc 1 0x32000000 \${sd_image_name}\; bootm 0x32000000
2. Stay in the bootloader until a choice has been made: setenv bootdelay -1
3. Don't power down the bootloader when idle: setenv boot_menu_timeout 99999
4. Always show the menu at boot: setenv stop_in_menu yes
5. saveenv

So now my phone dual boots, and I can choose if I want a more reliable phone now (Qtopia) or if I want to play with my future phone (Debian).

Configuring ssh for two host keys on the same host

Minor issue, but annoying: since both QTopia and Debian show up on 192.168.0.202, ssh will complain about changed host keys. Here is how to configure ssh to avoid the problem (in ~/.ssh/config):

Host debian
HostName 192.168.0.202
User root
HostKeyAlias debian

Host qtopia
HostName 192.168.0.202
User root
HostKeyAlias qtopia

This code has been take from moko_eightball by Jakob Westhoff: it just continuously prints the value of the three accelerometers.

#include <stdio.h>
#include <stdint.h>

void processInputEvents(FILE* in)
{
    int x = 0, y = 0, z = 0;
    while (1)
    {
        char padding[16];
        uint16_t type, code;
        int32_t value;

        // Skip the timestamp
        fread(padding, 1, 8, in);

        // Read the type
        fread(&type, 1, 2, in);

        // Read the code
        fread(&code, 1, 2, in);

        // Read the value
        fread(&value, 1, 4, in);

        switch( type )
        {
            case 0:
                switch( code )
                {
                    case 0:
                        fprintf(stdout, "x%d y%d z%d\n", x, y, z);
                        break;
                    default:
                        //warning( "Unknown code ( 0x%02x ) for type 0x%02x\n", code, type );
                        break;
                }
                break;
            case 2:
                switch ( code )
                {
                    case 0:
                        // Update to the new value
                        x = value;
                        break;
                    case 1:
                        // Update to the new value
                        y = value;
                        break;
                    case 2:
                        // Update to the new value
                        z = value;
                        break;
                    default:
                        //warning( "Unknown code ( 0x%02x ) for type 0x%02x\n", code, type );
                        break;
                }
                break;

            default:
                //warning( "Unknown type ( 0x%02x ) in accelerometer input stream\n", type );
                break;
        }


    }
}


int main()
{
    FILE* in = fopen("/dev/input/event2", "r");
    processInputEvents(in);
    fclose(in);
    return 0;
}

I've already mentioned that I'm running approx in the laptop and I configured the FreeRunner to access the laptop's cache. Here are the other customisations needed to have a decently working apt:

# cat /etc/apt/apt.conf.d/99freerunner
APT::Install-Recommends "false";
Acquire::PDiffs "false";

The rationale is that recommends would bloat a system that is supposed to be small, and pdiff requires more CPU, memory and disk space/time than it actually saves in bandwidth.

Thanks to Michael Banck and Peter Palfrader for helping me to find out how to disable pdiffs.

Earlier in the day, I wrote:

So yes, my laptop can now be turned into a phone charger with networking, DNS and apt cache services. I shall look into hooking that script into dbus to have it run automatically when the phone is plugged and unplugged.

It's not dbus, it's udev, and I've managed to do it.

It's an udev rule:

# cat /etc/udev/rules.d/z60_openmoko_net.rules
ACTION=="add", SUBSYSTEM=="net", ATTRS{idVendor}=="1457", ATTRS{idProduct}=="5122", RUN+="/root/bin/share-openmoko"
ACTION=="remove", SUBSYSTEM=="net", INTERFACE="usb0", RUN+="/root/bin/share-openmoko"

And a script:

# cat bin/share-openmoko
#!/bin/sh

if [ "$ACTION" == "add" ]
then
    ACTION=start
fi

if [ "$ACTION" == "remove" ]
then
    ACTION=stop
fi

INTERFACE=${INTERFACE:-"usb0"}
ACTION=${ACTION:-"$1"}

case "$ACTION" in
    start)
        logger -t openmoko "Connected, setting up network"
        iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE -s 192.168.0.200/29
        ifconfig usb0 192.168.0.200 netmask 255.255.255.248
        /etc/init.d/dnsmasq start
        echo 1 > /proc/sys/net/ipv4/ip_forward
        ;;
    stop)
        logger -t openmoko "Disconnected, bringing down network"
        echo 0 > /proc/sys/net/ipv4/ip_forward
        /etc/init.d/dnsmasq stop
        iptables -t nat -F POSTROUTING
        ifconfig usb0 down
        ;;
esac

The script has extra cruft that makes it double as a udev script and as a init.d style script, just because I didn't feel like abandoning the init.d style interface. However, udev handles it perfectly, so there's probably no use at all for the start/stop part.

This means that the interface and all supporting services will be brought up and down when the phone is connected/disconnected, and also when the phone is suspended/resumed. Of course, more fancy things can be plugged into the script, like syncing PIM info, file systems, turning on applets in panels, mounting phone file systems and whatnot.