Chamilo LMS

There is no way to find an open-source software to do this, as this requires access to a mobile phone infrastructure. However, there are systems around which make it very easy to register an account, get an API key and send a few SMS.

I believe a small plugin could enable this by plugging into the courses announcements system (would require hacks to the announcements mail-sending process, but no change to the database).

There is a REST interface for Clockwork explained here: http://www.clockworksms.com/doc/easy-stuff/http-interface/send-sms/ and the cost of each SMS is ~0.06€/SMS (it is still expensive, but it works to send them all around the world). You can send it to up to 50 numbers at a time, with a single REST call, which makes it practical for most courses.

The process to register an account with Clockwork is simply to register here: http://www.clockworksms.com/platforms/piwik/ (in the case of Piwik), register, confirm your mail, get an API key and register this API key in the Chamilo plugin's config page and... that's it... We could then add a "mobile phone" user field at the plugin's install time (or ask for the name of the corresponding extra field in the plugin configuration).

Ideally, the plugin would also send an e-mail to the teacher with the results of the message sending for each user, so the teacher knows if some people did not receive it, for example.

Finally, to avoid overcosts, the plugin should offer a list of checkboxes with each message type, and only send an SMS in these cases where the checkbox has been selected.

A landing page will be setup by Clockworks for us at http://www.clockworksms.com/platforms/chamilo/ This is where the plugin should send you to get an API key.