A large scale project to send one million messages a day to South African mobile phones, encouraging South Africans to be tested for HIV/AIDS, will go live December 1, after a pilot project showed that the messages led to a dramatic increase in calls to counselors at the National AIDS helpline in Johannesburg.

The BBC reports that Project Masiluleke will send one million free text messages a day – many in local languages such as Zulu – in what may be the largest ever use of mobile phones for health information purposes.  Its developers hope it will encourage hundreds of thousands of people to go for an HIV test in the first year.

The system sends the messages using a “Please Call Me” (PCM) service – a free form of text messaging, found across Africa, that allows someone without any phone credit to send a text to a friend asking them to call. Each sent PCM message has the words “Please Call Me,” the phone number of the caller, and space for an additional 120 characters. The extra space is normally filled with advertising, which helps offset the cost of running the service. About 30m PCM messages are sent every day in South Africa.

The system, which will also eventually be used to provide information about tuberculosis, has been developed and funded by a group of technology firms such as Nokia Siemens Networks, HIV charities, design firms and educational organisations such as National Geographic. It was launched at the Pop!Tech conference in Camden, Maine, BBC says.