The "Blue Pill" is a cheap STM32 Cortex-M3 based microcontroller board. It is popular because of its price and versatility. Now there is an updated variant, dubbed the "Black Pill" with a new STM32 microcontroller based on the Cortex-M4F (with a FPU). The Blue Pill uses the STMicro STM32F103C8T6 and costs less than $2. The new "Black Pill" is shipping in two variants, one using the STM32F401CCU6, the other using STM32F411CEU6. Both are Arm Cortex-M4F based microcontrollers. Black Pill: FT232RL FTDI USB to Serial Converter: ST-Link V2: STM32 Flash loader: Mbed OS: NUCLEO-F411RE: Note: Some of these links are affiliate links. Introduction to Android app development: Let Me Explain T-shirt: Twitter: Instagram: #garyexplains