Sunday, 24 March 2013

You CAN still get a pre-paid data SIM card in Japan

I read a lot of blogs stating you couldn't get a pre-paid SIM card in Japan. It's true that the big players (NTT Docomo, Softbank, AU) don't sell these anymore but turns out that there is still at least one way to do this.

A company called b-Mobile sells pre-paid SIM cards valid for 1 month (about $USD32) and 3 month (about $USD100) with 1GB of data each. Yes, I wonder if anyone goes with the 3 month option...

The cards don't support calls but they run on NTT Docomo's LTE, HSDPA, 3G networks and data coverage seems very good.

You can only get them from big retailers. In Osaka, that means BIC Camera in Namba or, in my case, Yodobashi Camera in Umeda. You also need to activate them in Japanese - with a Japanese mobile apparently. So it definitely helps if you speak Japanese, have a Japanese friend, or if you're super convincing, maybe you can persuade the sales person to do it for you. From what I could tell, the U300 SIM they used to offer in English, pre-activated 24 hours after mail order purchase is no longer on offer. :(

In my case, I've been running on a 1GB, 1 month MicroSIM for a week now and using SkypeIn for receiving incoming calls. Calls are very high latency (almost unusable) but it has served its purpose so far - if I get a call that isn't working well, I just fall back to contact via email.

Best of luck Japanese travellers!

Friday, 8 March 2013

The worlds ugliest webm streaming webserver?

I was trying to find an easy way to get low latency video from a webcam to a remote browser today. Requirements:

  1. Quick deployment
  2. Runs on Raspberry Pi
  3. Runs with out-of-the-box debs (see quick deployment)
My hacky solution was a Django python app that uses the StreamingHttpResponse class, gstreamer and a pipe. Disguisting, but works well. Sadly, latency is about 10 seconds to localhost so its not exactly live... 

import pygst
import gst
def grab(request):
  """ Return a webm live stream from the first attached webcam. """
  class VideoStreamer():
    def __init__(self):
      self.pipein, self.pipeout = os.pipe()
      self.player = gst.parse_launch ("v4l2src ! video/x-raw-yuv,width=640,height=480,framerate=10/1 ! ffmpegcolorspace ! vp8enc max-latency=1 lag-in-frames=1 ! webmmux name='m' streamable=true ! fdsink fd=%d" % self.pipeout)
    def start(self):
      fd = os.fdopen(self.pipein)
        while True:
      except Exception, e:
        print "Exception was ", e
    def __del__(self):
  return StreamingHttpResponse(VideoStreamer().start(), content_type="video/webm")

Requires pygst and django 1.5 (use pip).

Monday, 4 March 2013

Bricked Netgear Stora? Arduino to the rescue!

My latest attempt at getting offsite backups working for me in the most convenient manner possible involves scattering storage devices around at places I frequently visit such as relatives places, etc. I thought I'd re-purpose a Netgear Stora device I had lying about (P.S. Don't ever buy one of these if you value your privacy) by modding the firmware on it. Turns out, an arduino makes a great TTL serial adapter if you short the reset pin to GND. :) 

I'm also particularly proud of my ghetto MacGyver-like pin connectors. They were created with PVC tape rolled around the leg of a resistor and then cut into thirds and slipped over each pin to hold them in place. (Yes, I need to get myself some more electronics gear...)

Pin outs here in case anyone stumbles across this wanting to do something similar. :)