This Attiny85 module is the smallest arduino type of development board available. It has a USB connector on the PCB and the entire PCB is just a little bigger than the USB connector itself. Everything needed to program and power the Attiny85 is on board. When plugged into a computer it will draw power from the USB port. After programming it has a voltage regulator that can accept an input voltage of 7-35V and reduce that to the 5V required by the controller.
The Attiny85 is in the same family of microcontrollers as those on the Arduino Uno and Arduino Mega. The phyiscal size of the Attiny85 is the smallest available. The Attiny85 can be purchased and used alone but having an on board voltage regulator and programming interface is convenient.
The Attiny85 has a very small program space of 8KB. That’s plenty for many simple projects. There are just 6 I/O pins (3 PWM and 4 have a ADC). It’s a very powerful controller in a small package.
This board can do just about anything that a larger Arduino Uno could do but with less I/O ports and less program space.
4 x Attiny85 USB Module