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AutoStrap - a Self Tightening Strap

Hello world!

The AutoStrap was created to get rid of the hassle of tightening straps that are put on any part of your body. Just like the shoes from Back to the Future, you simply push a button and the strap will tighten until it is tight enough that it won’t slip off. This can be used to help those who have trouble putting on arm or leg braces as they do not need to bend down and forcefully tighten the straps. The video at the end of this Instructable shows it at work!

This is a pretty straightforward project with little technological knowledge necessary. A 3D printed arm mount holds a stepper motor that when turned on, wraps a strap around an axel. The other end of the strap is connected to a spring with a resistor inside. And once the strap is pulling hard enough on the spring, the resistor disconnects from its circuit which the Arduino will pick up and will tell the stepper motor to stop spinning.

The version that I have here is quite bulky and there are definite ways for it to be improved (which I will get into at the end). But if you want to try out what I got so far, let’s get into it!

Parts List:

- Any Arduino will be sufficient the smaller the better (I used a regular Arduino Uno for this project)
- Stepper Motor with driver (I used a cheap one that came in a basic Arduino kit)
- 2 Resistors of different values (I used a 1k and a 220 Ohm resistors)
- 1-2 Springs (I messed with different springs from this kit)
- 220 uF Capacitor
- Some kitchen Aluminum Foil
- A strap
- 9V Battery
- Misc electronic parts: Breadboard, wires, button, etc.

Tools List:
- Wire Stripper
- Soldering Iron
- Hot Glue gun
- Computer
- 3D Printer
- A lot of Patience

- Arduino IDE (which can be set up by following this guide here)
- Fusion 360 or any CAD software
- Download stl files and arduino code from my github”

Link to article