Monday, December 29, 2008

iPhone and Android can tell when you arrive

Location apps that tell people "when" you arrive not just where you are.

When we tell friends in non-technical terms what we are doing at jTribe we usually say something like:

" We make applications that allow your partner to know when you are coming home".

The response we then get is:

" That means I don't have to call or message constantly where I am and what my ETA would be? I could use that."

jTribe has finished the first application that solves the problem of "personal ETA notification" (Has anyone a better term for that?).

The application is called "Going Home" and it is based on the problem many families have: Someone is waiting at home and would like to know when you arrive.

The underlying User Intention

#1: I want to meet someone at their place.
#2: I want to let them know how long before I arrive.

The 4 Ingredients
To solve the problem of letting someone automatically know when you are going to arrive we need four ingredients:
  1. Destination - of the place we want to go (e.g. home)
  2. Contact - details of the person waiting for us at the destination
    (e.g my partner waiting at home)
  3. Current Locations - where we currently are
  4. Notification - let them know
Hey, the iPhone or Android G1 is providing exactly what we need. It has an Address Book with contacts. The contact often have an address which we could use as destination. The GPS in iPhone or Android phone provides current location. Great, almost done.

Stop, we still need a Solution for Notifications
TXT/SMS would be good for that because it a great mean to notify people instantly. Email would work too but does not have the instant characteristics of TXT/SMS. We settled for a combination of Email and TXT/SMS. At the start of the trip an Email is used to send a shared map link to the person who is waiting. TXT/SMS messaging is used to notify the person when you close to their place.

Unfortunately, the iPhone does not let you send TXT/SMS programmatically. Yes, it's true Apple still hasn't included it in their last iPhone 2.2 update. We thought there is no point waiting until Apple may or may not include an SMS API. So we had to integrate with a TXT/SMS gateway to send messages on behalf o the user. The issue with that is that these gateways are not free and someone has to pay for each SMS that gets sent. But without SMS the whole solution would be pretty much pointless. On the Android phone it would be possible to let the phone send SMS.

The Frontend
The primary frontend for the person that is travelling is either the iPhone (Android G1 is coming soon). As long as the iPhone application is running in the foreground it can constantly submit the current location to the backend server.

SMS will not be sent from the iPhone but from the backend server.

The person who is waiting has a different frontend. They receive an email with the shared trip map. They can then use the web browser to live-track the traveling person.
They will also receive an SMS when the traveling person is close enough.

The Backend
One key component of the solution is our FirePin platform. We use it as a backend to store all the user's locations so it can be shared with the person waiting. It also allows that person to track progress of your trip in real-time. (Sample of a shared trip)

FirePin Recap: The FirePin platform that allows recording and tracking of locations via the iPhone and Android G1 (and Symbian S60 soon). Basically, FirePin is a generic platform for location tracking and trip history. Because people store quite a number of trips on our FirePin servers we could almost call FirePin "personal GEO location hosting". (Rem: currently we got almost 2 million GEO locations in the FirePin database).

With the limitation of the iPhone we decided to extend the backend to include Notification services. Based on the locations that are constantly submitted to the FirePin server the service calculates the remaining distance to the destination. When a distance is close enough it will send out the TXT/SMS message to the person that is waiting.

Did I mention that the backend is written in Ruby On Rails.

The Integration
Integration between the iPhone and the Ruby On Rails backend is done via JSON and REST. Check out

The End?
No this is not the end. It's the beginning of a series of apps from jTribe. Going Home is just the start. We have many ideas of location-aware applications that are getting more micro-social .


Raj said...

Fantastic stuff - great idea. I have bookmarked your post at

Wish you all the success with this app ;-)

firepin team said...

Thanks Raj,
we will do out best to realise those ideas.