Developers from ArduCAM created modified Raspberry Pi. The board has a 24 x 24 mm and contains:

SoC ? Broadcom BCM2835 ARM11 Processor @ 700 MHz (or 1GHz?) with Videocore IV GPU
System Memory ? 256MB/512MB LPDDR2
Storage ? micro SD card slot
USB ? 2x micro USB ports including one for power only
Camera ? 1x MIPI CSI connector supporting 5MP or 8MP Pi cameras (dual camera support)
Expansion ?
- AV output header
- 16-pin and 8-pin headers (unpopulated) with GPIOs, 2x I2C, UART, 2x SPI
Misc ? Power LED
Power ? 5V via micro USB port, or battery header
Dimensions ? 36x36mm (Module only: 24mm x 24mm)
Weight ? 5 grams

Operating Systems which support Raspberry Pi B also support this board.

ArduCAM: http://www.arducam.com/24-24mm-coin-size-raspberry-pi-compatible-board/

Via from http://www.cnx-software.com/2016/07/18/arducam-has-designed-a-tiny-raspberry-pi-compatible-module/?utm_campaign=shareaholic&utm_medium=google_plus&utm_source=socialnetwork