Samsung E1107

The Samsung E1107 (also known as "Crest Solar" or "Solar Guru") is a mobile phone designed for a rural lower budget market. The handset has a solar cell on the back and is made from recycled materials. It was first released in India on July 10, 2009 with an initial price of ₹2,799.

Features
The feature set is spatial (clock, alarm, timer, stopwatch, organizer, T9 predictive text, calculator, converter, 10 polyphonic ringtones, 5 menu color themes, 3 wallpapers, 2 games (Sudoku and Super Jewel Quest), vibration, profiles, phonebook (500 entries) and call log (30 entries)).

Additionally it has features especially interesting for a rural consumer market like an LED lamp and power saving mode. It also has support for a built-in phone tracker and SOS messages. No connectivity like USB, Bluetooth or Infrared is supported.

Applications
The Indian version also included a proprietary "Mobile prayer", a specialized feature for Indian religions that includes prayers and wallpapers for each as well as alerts for prayer time.

Solar panel
The battery supports up to 570 hours of standby or 8 hours of talk time. It can be charged through the solar panel for up to 10 minutes of talk time per hour of charging. According to the user manual the phone is not supposed to run on solar power alone for an extended period of time.

Usage
In 2010, a Samsung E1107 was found as contraband in at the Central Prison at Puzhal. Prison inspectors were also searching for a battery and charger until they realised that the back of the device had a built-in solar panel that allowed it to be charged even while it was being used.