This safety sensor sleeve is part of the fusion design challenge. This product has many applications, but one of which is safety. The way this sleeve works is by having input optic cables that runs through the lattice tunnels and output cables that come out in the middle. By using light you are able to detect how much bending is occurring in the arm and even 3D model the arm for many applications using machine learning and neural networks. When you bend your arm parts of your arm push more against the sleeve causing more light to be received from one cable to another through a process called frustrated total internal reflection which occurs when the cables are closer to parallel to one another.
Now that I have explained how this design works on a basic level I will go into how it applies to a wearable safety device. A person can choose to program a specific arm movement pattern into a signal that will connect with Bluetooth to your phone. Then your phone will call the police and send them your location through a simple app. This allows for a subtle way to call for help by simply bending your arm in a specific pattern without alerting your aggressor. This device can be hidden under ones shirt and is fairly comfortable, it can be kept on throughout the day or simply slid on during your commute to and from work. This is safer than other designs because unlike other designs (ex pulling out your phone or a wristband) your aggressor would have no way of knowing that you are signaling for help.
Print one of the center stl files and two of the outside stl files and use the post printing instructions to put them together and form a sleeve.
I included one picture with blue light to show how this technology works for a block and that is of a different design that is a proof of concept from a colleague of mine named Patricia A. Xu. This is an up and coming type of sensor technology that has been tested in the lab I work in and is showing great promise for many applications from safety to physical therapy to virtual reality and many more.
NA flexible (ex tpu, I used a resin called SIL)
This is a lattice print which may require a mid-high end printer to come out nicely. Here are my suggestions to get the best quality print. Possibly try printing with soluble supports if possible. Try using a .2mm nozzle and a .1mm layer height. If you are still having trouble possibly try an SLA printer, however it should be possible with a well calibrated FDM printer.
putting the pieces together
The easiest way to attach the pieces is by tying approximately 5 knots with string for each connection and using an epoxy.
I designed this in fusion 360 using lattices and patterning