Industrial - Honours

Pressure Technologies P.T.S

The P.T.S was designed to help address the common occurrence of injuries in offroad motorcycle riding disciplines such as motocross and enduro. The system uses innovative pressure sensing components to determine if the rider is applying too much or too little pressure while riding and gives visual feedback when required.

Project Context – Injury Prevention in offroad motorcycle riding

I’ve been riding offroad motorcycles (dirtbikes) since I was 4 years old. So, when it came time for my honours project, it was an obvious choice. As with most action sports, injuries are a very frequent occurrence in offroad riding. The list of injuries was unnervingly long and so the decision was made to focus on injury causes rather than the resultant injuries themselves.

From the literature review and primary research gathered, the topic of armpump, or Chronic Exertional Compartment Syndrome (C.E.C.S) stood out as a common issue. Many riders indicated multiple experiences of armpump, in which the forearms swelled to the point of diminishing strength and loss of hand dexterity. Some riders even stated it as a precursor to their crash. Armpump can be caused by a number of factors, chief among which is incorrect riding techniques. Interviews with industry experts provided crucial insights on aspects of riding techniques to monitor in order to minimise or eliminate the onset of armpump

The Pressure Tracking System (P.T.S)

The P.T.S system utilises embedded pressure sensors to measure the force exerted by the user on the handlebar grips and the motorcycle side-panels. By utilising baseline values taken during low-intensity riding sessions, the system can detect whether the user is exerting too much or too little pressure during regular or high-intensity sessions.

Inputs

The P.T.S device utilises 4 removeable force-sensing resistors (FSRs) in each hand-grip to monitor pressure at all points of contact with the user’s hands. These FSRs are also what make up the sensor arrays on each side of the motorcycle to monitor pressure exerted by the legs when squeezing the bike. This data is sent to the control unit to be compared against the baseline values. After the comparison, the control unit determines whether corrective visual feedback (flash peak light) is required and sends the necessary signal via Bluetooth to trigger the peak light to flash.

Control Unit

The control unit is the brain within the device. It records and analyses all the data retrieved from the two inputs and determines whether the peak lights should be triggered in order to correct poor body positioning. The control unit houses a Lithium Polymer battery that powers both input sensors and the necessary electronics to communicate with the peak lights and the user’s smart device via Bluetooth.

Outputs – Helmet-peak Feedback Lights

These two lights are mounted under the rider’s helmet peak and flash a red LED when technique corrections are needed. One light flashes for over-exertion of pressure on the grip sensors and the other flashes for under-exertion of pressure on the side-panel sensors. They are powered by a 330mAh 3.7V LiPo battery and can be adjusted to suit high-brightness environment (higher voltage/brightness) or low-light conditions (lower voltage/brightness) in order to produce the minimum noticeable feedback.

Pressure Tech App

The device would function similar to a Garmin or Fitbit fitness tracker and utilise a free downloadable app from the user’s relevant app store (e.g., Google Play store or Apple App Store) that allows them to view their data. The official Pressure Technologies website would also connect to the user’s account and allow them to view their data on a laptop or computer.

Personalisation

The design outcome had to be desirable by a very large and varied group of users. This variety pushed the design to be more conservative with the option to choose coloured components based on personal tastes. Not only were these options to suit the user’s personal tastes but also the ability to match to their current or future protective gear choices, or to match the colour of their motorcycle.

The personalisation comes in the form of the coloured retaining strap on the control unit and the enclosure colour of the peak lights. These flashes of colour are contrasting the charcoal/black colour of the control unit enclosure. White pinstripes and small square stud patterns on the control unit also help elevate it above just a boring black box. This stud pattern is continued on the mount for the peak light with the release tab.

Manufacturing

The P.T.S device only uses traditional manufacturing methods to minimise production costs. The majority of the custom components in the device are produced by either one-stage or two-stage injection moulding. The control unit top enclosure, peak light top enclosure and the grips are the three components that feature two-stage moulding to create the buttons and over-grip respectively. The second stage moulding process the grips undertake also produces a cavity for the FSRs to slide into during assembly. This also means that the FSRs can be replaced or moved from grip to grip if damage occurs. The control unit mount clamp is made using a process of metal casting, polishing and anodising. The fasteners, batteries and LEDs are the main standard components sourced for the device.

Final Design Prototyping

Sean Mortensen

Sean’s goal and passion is to create products that people connect with on a level beyond their base functionality. Sean describes himself as a kind, hardworking and enthusiastic person who is always eager to learn new skills to produce the most effective design outcome.