(Another!) Mobile app to share where you are

Mobile location sharing is something that I keep coming back to: from finding where my phone is using GPS, Bluetooth, WiFi Access Points, GSM Cell Ids, using my own hand-rolled systems or newer services like Google Latitude, dopplr, OpenCellID and Brightkite.

There is something about the promise of location-based apps which I find very exciting.

This is my excuse, at any rate, for sharing my latest bit of tinkering. 🙂

The stuff that I’ve tried so far has been focused on long-term sharing – apps intended to run in the background on your phone all the time, sharing your location with a pre-arranged list of friends and family who have signed up to the same service.

I’m playing with an app which comes at this from the other angle: an app for specific occasions to share your location. Not something to run in the background all the time, but an app to use when you want to let someone know where you are – a specific person. This could be a friend or family member, or a colleague or client (perhaps someone who hasn’t signed up to any service that you have).

To save time, I’ve been reusing some of the Fire Eagle Guest Pass code that I wrote at Yahoo’s Hack Day last May as a web service.

I’ve added a mobile client for Windows Mobile.

The client app can:

  • Update your current location to Yahoo! Fire Eagle
    • using your GPS location, GSM Cell Id, manually entered address, manually entered free text, or location from Outlook diary

  • Provide (time-limited) access to your location on Fire Eagle
    • sending it by email or SMS
    • copying a URL (or TinyURL) to the clipboard ready for sharing by Twitter, IM or other services

As I discussed when I wrote the Guest Pass code, your location can be viewed in a:

  • desktop-friendly AJAX Google Map
  • mobile-friendly static map, providing directions to you from the recipient’s current location

Access to your location will expire after a time period that you define from the mobile client, or can be revoked at any time.

I’ve also started playing with automating some of this in response to SMS messages.

If someone sends me an SMS message containing “Where are you?”, the app can be automatically launched and prepare an automated reply.

By registering the client in the Windows Mobile Registry, it means that the app doesn’t even need to be left running for this to work.

It’s a very neat API which doesn’t require any battery-intensive polling.

For now, I’ve added a filter so that this only happens automatically for text messages received from a pre-approved mobile number. Perhaps I’m being over-cautious… 🙂

There are some issues…

The fact that ‘Guest Pass’ is hosted on Google App Engine means that you need to provide Google credentials. It’s a shame, and a bit clunky – if only Yahoo! offered web service hosting, then I could reuse the OAuth credentials I collect to update Fire Eagle location.

And I’m not sure that the separation between updating location and sharing location might not be a little clunky. It has some advantages – such as being able to continue to update your location after you’ve sent someone a Guest Pass. This wouldn’t be possible if you sent someone a static map image or text description of where you are. But even so… the client GUI could be a little clearer.

But it’s a start – and already something that I’m finding useful. The approach of share-your-location-when-you-want-to rather than relying on running an application all the time is very appealing to someone who’s always worried about their battery dying! 🙂

If you want to give it a try, you can download it here for touch-screen Windows Mobile phones.

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3 Responses to “(Another!) Mobile app to share where you are”

  1. […] dale lane fan of all things mobile, father of small girls, IBM code monkey, youth charity trustee… « (Another!) Mobile app to share where you are […]

  2. Guilherme says:

    Your software looks promising however it is not working properly in Brazil. It is not able to use CellID identification.
    I would really like to use this feature. Or maybe the same feature as latitude use instead of GPS (which drain my battery).
    Any reason to not be working in Brazil service provider CLARO ?

  3. dale says:


    Sorry – I don’t know much about the state of Yahoo’s cell ID database for cells in Brazil.

    Kind regards, D