There are many versions of the ATTINY85 Fuse Resetters on the NET. This is based on the work of Arduino (blog, the above schematic) and Ralph Bacon (GIT, Youtube video above). The main benefit of this device is sacrificing the reset pin on an ATTINY85 for use as a GPIO.
The main differences with the previous builds are I embed a dedicated Arduino Pro Mini and give a simplified build instruction.
My desk real estate is precious and I did not want to dedicate an UNO for this infrequent process. A separate 12V power supply is needed. I use an unused 4A Switching Mode Power Supply. I understand 12V batteries can be used. A 500mA smooth supply seems a prerequisite.
As a nod to Ralph, I included to optional steps of including a Buzzer and LED indicator.”

Link