Fitbit Sync Decode - Part 2

If we think about what information would need to be passed back and forth, that might help when looking at the sync data, and provide ideas about what knobs to turn.  A good source for inspiration here is the user manual.

This summary data would probably go in both directions:

• Calories
• Steps (walking + running)
• Elevation (floors, distance)
• Distance (native units)
• Active score (# plant leaves, score)

These would be passed from device to server:

• Timer information (start/stop)
• Steps data series (per minute)
• Elevation data series (per minute)
• Battery level (charging status?)
• Firmware version
• Beginner mode flag (?)

These would be passed from server to device:

• Enable/Disable flag for all of the displayed metrics
• Chatter text
• Current date/time
• Stride length (walking, running)
• Body stats / BMR (for calorie estimations)
• Timezone
• Units (distance)
• Time format (ie. 12/24 hour clock)
• Left-hand/Right-hand mode
• Silent alarm settings (including repetitions on specific days)
• Sleep tracking mode (normal vs. sensitive)

Some additional inputs:

• There are 10 leaves on a fully-grown plant
• The device can store 14 days of minute by minute data, and summary data for 30 days
• The device can have 8 separate alarms

Fitbit Sync Decode - Part 1

There are two sync blobs available to us for inspection.  One blob is from the POST to the server, and the other is the server's response.

An example request:

POST http://client.fitbit.com/tracker/client/message?p_lcl=en_US HTTP/1.1

Content-Type: text/xml

User-Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; WOW64; Trident/4.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0)

Host: client.fitbit.com

Content-Length: 3328

Pragma: no-cache

Cookie: JSESSIONID=...

<?xml version="1.0"?>

<galileo-client version="2.0">

<client-info>

<client-id>...guid...</client-id>

<client-version>1.0.0.2292</client-version>

<client-mode>force-sync</client-mode>

<dongle-version major="1" minor="1" />

</client-info>

<tracker tracker-id="FFFFFFFFFFFF">

<data>...base64-encoded data...</data>

</tracker>

</galileo-client>

An example response:

HTTP/1.1 200 OK

Server: Apache-Coyote/1.1

Expires: Thu, 01 Jan 1970 00:00:00 GMT

Cache-control: no-store, no-cache, must-revalidate

Pragma: no-cache

Content-Type: text/xml;charset=UTF-8

Content-Language: en-US

Vary: Accept-Encoding

Date: Sun, 06 Jan 2013 20:25:11 GMT

Content-Length: 17077

<?xml version="1.0" encoding="UTF-8" standalone="yes"?><galileo-server version="2.0"><server-version>URL: https://wush.net/svn/fitbit/weightsite/branches/Release_20130104

Last Changed Rev: 44872

</server-version><ui-request action="done"><client-display height="450" width="650" minDisplayTimeMs="20000" containsForm="true"> ...html...</client-display></ui-request><commands><connect-to-tracker connection="disconnect" tracker-id="FFFFFFFFFFFF"/></commands><tracker type="megadumpresponse" tracker-id="FFFFFFFFFFFF"><data>...base64-encoded data...</data></tracker></galileo-server>

Comments:

• This is a trace from a forced sync, where I clicked the Sync Now button in the FitbitConnect UI, so it also contains an HTML page for display.
• The blobs are base64-encoded since they are part of an XML body.
• The blob data is also written (not base64 encoded) to the sync log on my desktop

Next up... start digging into these blobs.

Fitbit Text

Just for fun, keeping a list of the chatter text the Fitbit throws at me:

• HI THERE
• HOWDY
• I LIKE U
• GO
• STEPGEEK
• HELLO
• CLIMB IT
• WOOT!
• ITS ON!
• FASTER
• IM READY
• WALK ME
• SMOOCHES
• STEPITUP
• HOLD ME
• HEY HEY!
• BON JOUR
• MOVE IT
• CHEERS
• UCANDOIT
• LETS GO
• HUG ME
• READY?
• GOOOOAL
• VAMOS
• YOU ROCK
• BURN IT
• HIGHFIVE
• LOVE YA
• WHATS UP

FileScanner

Started working on a file scanner today.  This project is a result of my cluttered hard drives.  I have music and photos and videos all over the place, with duplication, etc.  I need to consolidate them, index them, and make sure they are all stored safely on one set of RAID-1 drives.

This is also an attempt to get out of the C# trap.  Since I use C# a lot at work, it's become my go-to language.  This sucks in a non-MSFT world, like the Mac I use at home, so I'm writing the scanner in Java.  I used to have mad Java chops, but have mostly lost them over the past 4 years.  Hopefully this will bring some of that back.

Ideally, I'd like to write this in Objective C or C++, just to really push myself, but I don't want to spend a ton of time on this particular project.  Java is a lot like C#, so I'm hopeful this will be wrapped up fairly quickly.

Fitbit Sync Experiment

Managed to screw up my Win7 VM by installing the USB filter driver.  Had to go back to a system restore point.

On another note, I tried a little experiment today.  I didn't let my Fitbit sync all day so I could see if there would be a difference in the size of the data payload when I eventually did sync it.  There was.

My Fitbit sent 2380 bytes to the service.  My wife's Fitbit was home with her all day, syncing regularly, and her Fitbit only sent 784 bytes.

Need to decode the sync packets.

Fitbit One Sync Logs

My first order investigation of the Fitbit One involved the following:

• Installing the FitbitConnect software on my Win7 VM
• Setting up the device with my account
• Forcing a sync
• Finding for the sync logs

The FitbitConnect options panel allows the specification of a proxy server, so I obliged and used Fiddler to capture network traffic.  

I figured the sync logs had to be stored somewhere on the Win7 filesystem, since the FitbitConnect UI mentions them (provides a checkbox to keep them for 5 days), and so does this guy.

On my install, the logs were found under C:\ProgramData\FitbitConnect\Logs.  An example filename is log-20130104004939.txt

UPDATE: On my iMac, the log is here: /private/var/run/com.fitbit.galileod.log

Scanning the logs I see scattered bits of interesting things.

1. The server is basically in control of the FitbitConnect UI.  On almost every action, the server returns an HTML page embedded in the XML response.

2. Among other things, the service also appears to provide the display strings to be used on the device.  For example, here is part of the data blob that the service provided in one of its responses:

    0000020: 0b00 5045 5445 5220 2020 2020 4855 4720  ..PETER     HUG 

    0000030: 4d45 2020 2020 5741 4c4b 204d 4520 2020  ME    WALK ME   

    0000040: 4845 5920 4845 5921 2020 0000 0000 0000  HEY HEY!  ......

3. The server classifies me as "obese".  While I can't disagree with this, it caught me by surprise that this is part of my account profile.

            var props = {

                'Android App Version': '',

                'iPhone App Version': '',

                'Has Android App': false,

                'Environment': 'prod',

                'Has iPhone App': false,

                'User Age Range': '35-44',

                'Body Type': 'obese',

                'Gender': 'male',

                'Locale': 'en_US',

                'Premium': false,

                'Premium Expired': false,

                'Platform': 'Fitbit Connect',

                'Facebook Linked': false,

                'Height': '76.02362',

                'GoalPrimary': 'steps',

                'GoalWeight': '',

                'Operating System Version': osVersion,

                'Paired Aria': false,

                'Paired One': true,

                'Paired Zip': false,

                'Paired Flex': false,

                'Paired Ultra': false,

                'Paired Classic': false

            };

More later.  Planning to add a USB filter driver to capture traffic at the dongle.

Fitbit One

Gave the wife a Fitbit One for Christmas.  She's really enjoying it, and today (yesterday?) I bought my own.

Unfortunately, my interest is less about fitness and more about learning how it works... though I am interested in the fitness side of it too.  (For example, I'm sure it will be frowning at me tomorrow for the amount of sleep I'm not going to get tonight.)