What is this—a logic board for ants? Not quite, but weighing in at a whopping 1.0 gram it's definitely the smallest we've ever seen. With the hard work out of the way, we pause to see what makes the Pencil so smart:

STMicroelectronics STML151UCY6 Ultra-low-power 32-bit RISC ARM-based Cortex-M3 MCU

STMicroelectronics STMLS05 5-channel PMOS load switches

STMicroelectronics STM32L052T8 32-Bit ARM Cortex-M0+ Microcontroller w/ 64 Kb flash

Maxim Integrated MAX11290 24-bit delta-sigma A/D converter (likely)

Cambridge Silicon Radio (Qualcomm) CSR1012A05 Bluetooth smart IC

Bosch Sensortec BMA282 accelerometer

Maxim Integrated MAX44284 high precision current-sense amplifier