Sunday, December 30, 2012

Wiimote+nunchuk web surfing in linux

At this point, messing around with the wiimote probably seems dated, but hey, I have one lying around with a motionplus and nunchuk. The final outcome of this post if you follow it- you'll be able to control your mouse cursor with the nunchuk analog stick, scroll up/down/left/right with the wiimote d-pad and left/right click with either the wiimote or the nunchuk. Let's get started.

  • A wiimote
  • A wiimote nunchuk
  • A linux system with the uinput kernel module
  1. Clone my fork of cwiid into a directory of your choice(wiimouse for example here)
    git clone wiimouse
  2. cd wiimouse
  3. aclocal
  4. autoconf
  5. ./configure --with-cwiid-config-dir=/etc/cwiid/
  6. make
  7. sudo make install

    Note that by default this will install everything using a prefix of /usr/local unless you pass --prefix=some_other_directory to configure so make sure whatever prefix you use is in your path.
  8. sudo modprobe uinput
  9. Create a new config file for the plugin I wrote by creating the file /etc/cwiid/nunchuk_stick_ptr and adding the text below to it
    include buttons
    Plugin.nunchuk_stick_ptr.X = REL_X
    Plugin.nunchuk_stick_ptr.Y = REL_Y
  10. sudo wminput -c nunchuk_stick_ptr You will see this message appear: Put Wiimote in discoverable mode now (press 1+2)... Do as it says and press buttons 1 and 2 on the wiimote then release them, the LEDs on the wiimote will blink for a while then the terminal where you entered the previous command will say: Ready.
  11. Now try moving the nunchuk analog stick and it should move your cursor around. Adjust /etc/cwiid/wminput/buttons if you want to change button mappings
Note: if you do not want to have to run wminput as root, you can configure things so that uinput may be accessed by users in the wheel users group. To make this happen, create a udev rules file in /etc/udev/rules.d/ with a name of your choosing, for example /etc/udev/rules.d/uinput.rules which contains the following line of text:


If you've already loaded the uinput kernel module prior to creating this file, you'll have to unload the module:
sudo rmmod uinput
and then reload it:
sudo modprobe uinput
Now you should be able to run wminput without sudo (assuming your user is in the wheel group)

Friday, June 15, 2012

Fat Secret calorie counter access with python

This post complements my earlier discussion of the Withings scale API here:
I've written a convenience library in python that simplifies the process of retrieving protein, carbohydrate, fat, and calorie data from Fatsecret along with several other features from the REST API. To make use of the library you'll need to register as a developer at the link below:
After registering you will be given a consumer/API key and secret which you will need to use my python library. Once you have your key and secret, download the python library with the following command:

git clone

The library comes with the example below that demonstrates its usage. To use the example, replace the strings 'your_key_goes_here' and 'your_secret_goes_here' with the key and secret you were assigned after registering as a developer.
Note that the example above makes use of pandas to plot timeseries. You can get the latest pandas with this command:

git clone

I've tested the example above with the stable 0.7.3 release as well.
Once you paste your key and secret into place and install pandas you can run the example as follows:


Assuming you already have some data recorded with fatsecret, you should get a plot like the one below after running (click on the image to see a larger copy):

Monday, May 21, 2012

Withings wifi scale python dashboard using matplotlib and pandas

The Withings wifi scale is a great bit of hardware, much more visually appealing than my handmade equivalent and wifi makes it standalone, also a big advantage over my bluetooth scale. I've been using the scale to log my weight and using fatsecret to track caloric intake for a while now and decided it would be nice to make a dashboard integrating data from both sources. The plots on Withings' website leave much to be desired. Thankfully, both Withings and fatsecret have APIs which make third party apps possible. Below I'll show some code that uses the rauth library to access both services. rauth provides OAuth 1.0/a, 2.0, and Ofly consumer support. You can install rauth using easy_install:
sudo easy_install rauth
Before using the Withings and fatsecret APIs, you'll need to register as a developer, you can do that by following the links below:
Withings developer registration:
If you just want to extend the code I provide further down you can fill an arbitrary value for the "Application Website" and "Organization" fields and leave the Callback URL blank. Otherwise, fill in those fields according to your needs. Once you've registered as a developer with both services you will have your Consumer Key and Shared Secret which you will need to send API requests. Now grab my python code from github:

git clone

The git repo has two files: actual library itself) and (seen below). Open up and fill in your consumer key, consumer secret, and the email address you used to register with Withings as indicated. Using the library is pretty straightforward: instantiate a withings object and then just call get_weights() to retrieve a list of weight measurements and an associated list of dates (in seconds since the epoch format) which you can then use however you'd like. Note that the very first time you run you will be prompted to authorize the app to access your withings account by pasting a URL into your browser. Once you go to that URL and login, you will see a screen like this:
After you click "allow" you will see an oauth token string as shown below. Copy just the part after "oauth_verifier=" , in this case PZBDNyyuxDnGkeMxccY.
Paste the "PZ..." string into your terminal where prompted, hit enter, and you should get a graph like the one below.(Click on the graph to see a larger version) I used the python package pandas to treat the weight data as a time series and get nice date labels on the x-axis as well as to plot the smooth red rolling average of the data.
In an upcoming post, I'll discuss similar code that retrieves data from fatsecret to generate plots like the one below:

Wednesday, January 11, 2012

Gymnastics tap swing trainer

Timing is one of the things I've found most difficult to pick up while learning basic gymnastics. This is especially true when it comes to high bar/strap bar giants and tap swings. If I just blindly practice, I tend to tap far too early. For back giants, the tap is the moment when you transition from a hollow to an arch then back to a hollow again. To facilitate switching from hollow to arch at the right time I built the device you see in the video below. I suspect it would also work well for kip timing (it would tell you when to bring toes to the bar). It's basically a beam break sensor, like you might have at the bottom of your garage door, except it runs on batteries and beeps whenever something crosses between the flashlight and sensor. The idea is that you place the flashlight and sensor on either side of the high-bar at the location where you should ideally tap and then as you swing you just wait to hear the beep before switching from hollow to arch.

Here you can see and hear the tap trainer in action- I know my form is terrible, the video is just to show you how the device works. That high pitched beep you hear every time I approach maybe 30 degrees away from vertical is the sensor detecting me crossing its path and then beeping.