Electrical System Overview
Our electrical system consists of a battery to power the motors, several different sensors, and an electrical box to connect it all. The main focus of the electrical team was to make durable, reliable and neat electrical system.
Potentiometers were attached to the base of each wing with a 3D printed mount where the bottom
of the linkage overlayed the backboard. The base of the potentiometers are attached to the linkage
so that it rotates as the wings move, whereas the shaft is press fit into the backboard so it remains
stationary as the wings move. Mounting the potentiometers like this allows us to keep track of the position of the wings.
Flex sensors were attached to the harness at the top of the shoulder straps and pulled taught with rubber bands that were sewn into arm bands. As the wearer moves their arms to an angle the flex sensor also moves
The electrical box was split into three sections; the battery, the breadboard, and the arduino.
The electrical box was designed with holes in all of the walls such that wires could enter the box and wires could thread between the different sections.
The lid and walls of the electrical box is painted black for aesthetic reasons to match the backboard and the linkages The walls press fit into the
backboard, and the lid rests on the top and is held in place with black electrical tape so that it is easy to remove.
The electrical involved in the wings were a bit scattered so a major challenge involved in the electrical work was wire routing. The flex sensors, batteries, motors, and potentiometers were all fairly close to the electrical box so routing wires from each individual electronic part to the electrical box. The challenging part was attaching the two ultrasonic sensors positioned at the tip of each wing to the electrical box. This was risky for 3 reasons; that is a far distance for wires to travel, the wires are traveling over moving linkages, and each wing had eight separate wires coming from two different ultrasonic sensors that had to travel from the ultrasonic sensors to the electrical box.
The solution we ended up implementing was to attach the wires to the metal fence wire that made up the feathers. This way the wires can serve two purposes; to transmit power and information between the ultrasonic sensors and the arduino, and to physically hold the feathers up when the wings extend upwards.
We chose a 12 volt drill battery to power the wings. The battery was chosen to be 12 volts because the nominal voltage of the motors we were using was 12 volts. The unconventional choice of a drill battery was because it was a very compact battery and was easier to store on the backboard than other batteries of equal voltage.