• They can survive for days without connecting to an electricity supply. Many rural villages have no access to electricity, and for villages that are connected, the supply is often sporadic.
• Cellular handsets are much less susceptible than laptops or personal computers to environmental conditions such as dust and humidity.
• Unlike a landline, owning a cell phone does not require a physical address. In a continent where temporary housing and migrant working prevail, having a fixed line is next to impossible.
• Given the economies of scale involved, and subsidization by the network service providers, cellular handsets provide one of the cheapest forms of available digital technology.
Storing and sharing images. Some members of our research group set about solving this problem. First, we decided that the software for searching and managing images on these handsets is insufficient because image collections grow beyond 100 or more photos. Many handsets can store thousands of images, but standard thumbnail browsers are simply too slow to scroll through this many.
After developing several designs, one researcher implemented a system based on speed-dependent automatic zooming (SDAZ). This system works by scrolling images in a vertical, time-ordered strip in the center of the screen. As the user scrolls faster, however, the images shrink in size, as Figure 1 shows. The smaller size lets the user scroll through the images more quickly.
In our experiments, users could successfully navigate collections of 4,000 photographs. 5 This works because, even though the images are small, there is enough similarity between photographs from the same event to let users identify an event such as a beach trip because it will consist of many images depicting yellow land and blue sky. Thanks to a clever caching algorithm, the software runs smoothly on fairly common handsets—for this application we used a Nokia 6630 from 2004. The software makes it possible to store and retrieve collections of at least 4,000 images on existing handsets, letting us use camera phones as independent image-capture/storage/retrieval devices.
The need to implement such a system came about only because our background studies showed that users who owned only a camera phone would have to manage thousands of images on the handset itself. People who have dedicated cameras and computers should have no need to manage their photos this way. Yet many camera owners who took part in the trial wanted our software installed on their camera phone. Perhaps people in the developed world do not keep many images on their camera phones because the software impedes such use.
Sharing images. Another researcher working on our project started to look at the issues around sharing images. Instead of relying on technology infrastructure external to the phone—such as large displays, websites, e-mail, and laptops—he wrote a piece of software for cellular handsets that lets a user select an image and broadcast it to nearby users' screens over Bluetooth or Wi-Fi. Users could then see the image on their own display and even annotate that image or push one of their images to take part in the interaction. 6
We evaluated the system using groups of friends who had taken a trip together. These friends then described their day out to another friend who had not taken the trip. We chose this setup to elicit as much social engagement as possible—having several people try to describe the same event simultaneously—to see if the software held up and to monitor if this type of interaction worked or caused frustration. While the software held up to the constant swapping of images, the social interaction proved to be less straightforward.
We had hoped that the experience of using the system would be at least as enjoyable as swapping paper photographs. The actual results proved much more positive. First, the participants enjoyed seeing the photos while simultaneously hearing what they represented; with paper photographs, a listener hears the explanation first, then must wait until the photo gets passed down the line.
Second, what started as a simple show-and-tell rapidly became a highly interactive game, with users doodling on the photo being displayed. The software actually created a new type of social interaction wherein the participants would tease and playfully bait people displaying photographs. At the end of the evaluation sessions, our users refused to return the handsets to us—they were having too much fun using the software.
Again, the design for this system came about to compensate for the lack of Internet access and laptops that prevails in the developing world. Our system lets people with camera phones share their photographs with friends, but without using any more hardware or resources than those they already possess. In pursuing this alternative design, we serendipitously created a new type of social tool that we were unlikely to have found had more technology resources been available to our users.
• use handsets with 3G/Wi-Fi to download content,
• embed material in RFID tags to be read by suitable handsets,
• use ShotCodes or a similar tool to act as bar codes for selecting content on handsets containing the correct software, or
• use a large touchscreen device to select the content and let users enter their details, such as a phone number or e-mail address, so that content could be sent to them.