Scanadu Scout had developed a medical tricorder designed to work alongside an iPhone or Android handset.
Essentially, the Scout gathers data off a patient's forehead, which is subsequently displayed and transferred via Bluetooth Smart to one of the above-mentioned smartphones.
Currently, the device is capable of measuring heart rate, skin temperature, SpO2 (oxymetry), respiratory rate, blood pressure, ECG, and even emotional stress.
The device runs the 32-bit version of Micrium RTOS (real time operating system). Under the hood, CNX Software says the layout seems somewhat similar to the Laird Technology BL600 and RFDigital RFD51822 modules, both based on Nordic nRF51822, an SoC with Cortex M0 CPU, 256kB flash, 16kB RAM, and a 2.4GHz Bluetooth low energy transceiver.
Additional information about the Scanadu Scout can be found here.