Through working with the UK Space Agency on the Astro Pi project we’ve learnt about something called Outernet. Internet, Outernet – see what they did there? Outernet is a small company started by Syed Karim that broadcasts the most useful stuff from the internet via satellites in geostationary orbit.
Anyone receiving the broadcast then has access to all that stuff for free! The idea is that you can receive it in locations around the world where there is little or no internet infrastructure; or perhaps where the regime in power curtails access to information.
The content is the kind of thing you would find in a public library, with resources on human health, anatomy, encyclopaedias, how-to guides and news feeds. The data is broadcast cyclically so that any new receiver joining the broadcast can catch up with everyone else. The content received from the satellites is cached and served out to the users via http pages, meaning that any device with a browser can be used to read it (both Ethernet and WiFi are supported). It’s worth noting this is only one-way content, because you can’t send messages back up to the satellites.
Outernet also has a board of trustees whose job is to curate which content from the internet makes it into the broadcast. They’re also planning a voting system, which will allow anybody with internet access to participate in that process.
What’s all this got to do with Raspberry Pi? Outernet offers several different kinds of receiver; and the DIY one is based on a Raspberry Pi! After learning this, we decided to get one up and running at Pi Towers to evaluate the tech! So I contacted Syed Karim, and he generously sent us three DIY receiver kits to play with.
The main piece of hardware you need is a USB DVB-S2 dongle. The one included in the kit was designed specifically by Outernet to keep costs down. The dongle allows you to plug in the coaxial cable from a satellite dish and consume the data on the Pi.
In Europe, the Outernet broadcast is delivered through the Hotbird satellite, which has a footprint covering all of Europe, North Africa and parts of the Middle East. Because of its orbital position you need a slightly larger than normal dish to receive it. 60cm or larger is required, so we just ordered an 80cm one from Amazon.
Here it is installed on the roof of Pi Towers:
Aligning a satellite dish correctly can be a bit of a dark art, so we hired a professional with his own equipment to come and make sure it was pointing in the right direction.
It’s then simply a matter of burning a special SD card image provided by Outernet to an SD card, and booting the Pi up. This is essentially a minimal Linux ARM distro that has everything required to make the reciever work; it’s not Raspbian based and currently only works for the Pi 1 CPU.
Here’s our one:
The DVB-S2 dongle on the top plugs in via USB and has its own mains power supply. Currently, we think, we’re the first receiver online in the UK (up since the 2nd of June).
The software you use to access the downloaded content is called Librarian, and looks like this:
At the moment, it’s mostly news articles that are being broadcast. Each row in the list above is a different article, and each has one or two medium-resolution images along with the text.
There is also a nice configuration page allowing you to choose which satellite you’re using, and to monitor how large the database has grown.
New content coming down from the satellites is held prior to being added to your library, allowing you to choose which items to keep or discard.
Currently about 200MB of data per day is delivered through the broadcast; however, in the future they hope to offer up to 1GB per day.
We see this technology as being a fantastic solution to the problems with offline web servers that go out of date over time. When something is updated on the internet, the Outernet service can just retransmit the new version and all the receivers will update their local copies. We’re also aware that various NGO charities are already using Raspberry Pi networks in remote places with equipment like RACHEL-Pi (which we’ve covered here before). This system could easily be dropped into a network like that as an additional resource, providing a great source of searchable information.
We’re going to be watching Outernet with interest in the future, and we are considering the possibility of having some of our educational resources broadcast by their service.
If you want to buy a DIY reciever they’re available in the Outernet online store now.