The Teensy 3.2 is a breadboard friendly 32 bit ARM Cortex processor with high resolution ADC, I2S digital audio interface, 4 timers and 34 I/O pins including 21 high resolution analog inputs and 3 serial UART pins. Even works with Arduino software via the Teensyduino add-on.
The Teensy has a whole bunch of capabilities jammed into a tiny package that you can solder to directly or play with in a breadboard. On board is a 32bit ARM Cortex-M4 72 MHz CPU that features all kinds of I/O options including 34 available pins, 21 high resolution analog pins, support for SPI, I2C, I2S,CAN Bus, IR modulator, 7 timer and 12 PWM outputs. With all that it will suit a whole range of complicated projects.
With USB on the board you don't need a separate programmer module to develop for this board. Using your favourite editor you can program it in C or alternatively use the familiar Arduino software via the Teensyduino add-on
The tiny board is only 1.4 x 0.7 inches (36 x 18mm) in size. It has enough power via the on board 3.3v 100mA regulator to power external modules like ESP8266 Wifi.
The USB connection is a Micro-B like this cable if you don't have one already.
Look at all those useful pins...
Teensy 3.2 Pin Out