Google Glass: Trials and Tribulations

20 March 2014 - Filed under googleglass

"So I have a pair of google glass here if you want to play with it for the week, see what you can do".

This is how our weekly team meeting started on Monday. Needless to say I jumped at the chance, cleared my schedule and got my hot little hands on them the very next morning. I spent the next 3 days hacking together some little proof of concept applications to show at work. Glass development is easy to get into if you have previous Android development experience. It sits on top of the existing Eclipse tools and extends them via the Glass Development Kit (GDK).

There are plenty of resources out there to help get you started, so instead of duplicating those I figured I would share things that I had troubles with when I was starting out:

Disclaimer: At the time of writing the GDK is still relatively new; in the future these problems may be addressed and may no longer be an issue.

Getting down to it:

My Setup:

VPN Connection Issues

After hours (and hours) of investigation, it appears that a glass device connected to a device with a VPN connection cannot access addresses that reside on the VPN network. I connect through a VPN to gain access to machines in the office, including my development web server. I can make requests to my server through my tablet with no problem. The same request made via glass simply timed out.

  • Wireshark snooping on the packets showed that all requests made from the glass to IPs outside of the VPN routing ranges went out successfully. All requests made to IP ranges that would need to route through the VPN never went out on the wire - thus causing the timeouts.
  • Both wifi and bluetooth connection exhibit the same behaviour.
  • I connected via the Cisco AnyConnect client, although it is unclear if that matters or not - I have not tested this out via other VPNs.

No contextual voice commands

The "ok glass" menu system is awesome. How cool would it be to have something similar in your app? Really awesome! But we don't get it (for free) yet. The current voice recognition functionality will return the text string as spoken and it is up to you to determine matches or close matches.

Device to glass data transfer is not simple

I was hoping to be able to share data between an Android device and the glass itself. Ideally I wanted to push shared stored settings and notifications from a service running on the device (in the form of live or static cards), but there appears to be no functionality in the GDK to do this. A little digging has found that an ambitious developer has written up a bluetooth host/client to do this very thing; I have not had the time to try this out yet, but thought it worthy of note.

Authentication is tricky

Let me preface by stating that I haven't looked into authentication all that much, but by looking at currently supported glassware, they all use OAuth or OAuth2.

(GDK) Static cards cannot have a PendingIntent attached to them

There is no way to attach a menu (Intent action) to a static card put into the timeline through the GDK. It is only possible to do so using the Mirror API. To do this currently you have to create a live card.

Live cards must always include a PendingIntent

Nothing too crazy here. It states in the developer docs that a live card must including a PendingIntent, however if you forget to include this you will get no error, but the card will simply not appear when the application is run.


My demos proved worthy and our little mobile team is allowed to continue development with Glass.

Couldn't resist a Glass selfie or two


by Shayla Sawchenko