The Attiny85 is an 8-bit, Arduino-like microcontroller. Its like an Arduino but with a smaller form factor, slower processor and fewer I/O pins. Given that, when portability is required, it may be a better option than a full size Arduino.
The board contains all the supporting components. no need to connect to Arduino to program.
Although it uses the same Arduino IDE as the full size board, the settings and upload process is a little different.
See https://diyusthad.com/2021/07/digispark-attiny85.html for a complete list of proper settings and setup.
Pins
Being small, powerful, compatible and cheap, do not hesitate to use this in your next IOT protect.
Raspberry Pi and other Treats 