Draw Wire Sensor for Length Measurement

This is set of parts to buld a Draw Wire Sensor from an ID roller bind, a 10 turn potentiometer and a ball bearing.

To build this you need

1. a coil with spring and wire from an ID roller bind with 27 mm Diameter and 7mm height. The ID roller band I used has an extraction length of 70cm.
2. A 10-turn-precision potentiometer (e.g. BOURNS 3590S-002-102, Lin 10k)
3. 3 M4 Screws with length 35 mm
4. 3 M4 Screws with length 15mm
5. 3 M3 Screws with length 7mm
6. A 5mm / 15 mm Aluminium Rod with slit to hold the spring
7. A ball bearing with 6 / 19 mm inner/outer diameter and 6mm height

As your ID roller band may have different dimensions I attach the FreeCAD file that you can use to adapt the diemsions to other springs.