I've remixed the previous model in order to enhance it. Now M3 heat inserts are used, M5 screws are used for connecting the levier to the mechanism, a new design of base was created. The knob now is fixed to the levier using a M5 screw.

I've used an attiny85 that can be fixed directly under spring mechanism (the code is provided in the zip)

Parts required:

1x M4 x 50mm

3x M5 x 35mm

2x M5 x 20mm

1x M5 x 40mm

8 x M4 x 35 or 40mm

2x microswitch

1x Attiny85

1x extruder spring

Wiring:

one wire from ground to the both microswitch

pin 0 to the first microswitch

pin 2 to the other microswitch

13/1/2024 - pulley, spring base mount and spring holder updated - a full length spring can be used.

For the code get the .txt attached and change the extension to *.rar and unzip.