Raspberry Pi 3 Model A+ Block Connector You can get fast -

You can get fast - to save the data to a file in any FAT16 or FAT32 formatted SD card

PCB slotting

OpenLog (blackbox) is a data logger that works through a simple serial connection and supports microSD cards up to 64 GB

and standard 2

communicate with phones (say for payment processing)

Raspberry Pi 3 Model A+ Block Connector You can get fast -Raspberry Pi 3 Model A+ is a 1. 4GHz 64 bit quad core processor, dual band wireless LAN, Bluetooth 4. 2 BLE in the same mechanical format as the Raspberry Pi 1 Model A+ Broadcom BCM2837B0, Cortex A53 (ARMv8) 64 bit SoC @ 1. 4GHz 512MB LPDDR2 SDRAM 2. 4GHz and 5GHz IEEE 802. 11. b g n ac wireless LAN, Bluetooth 4. 2 BLE Extended 40 pin GPIO header Full size HDMI Single USB 2. 0 ports CSI camera port for connecting a Raspberry Pi Camera Module DSI