case studies

Creating a reliable new product for the leisure market - wireless bicycle gears

Brief: A manufacturer of high-end bicycle components required a wireless, battery powered system to electronically select gears. The manufacturer had an existing product which fulfilled their needs, but suffered from reliability problems. As such, they needed a new design to be developed. The device had to be reasonably priced, operate reliably under a range of weather conditions and add minimum weight to the bicycle. The battery was required to last a minimum of two years.

Solution: A set of three PCBs (Printed Circuit Boards) were developed, a control unit to be mounted on the handlebars, a rear derailleur unit and a speed sensing unit. Each was equipped with an RF (Radio Frequency) transmitter and receiver and a custom designed ASIC (Application Specific Integrated Circuit). Gear shifting was achieved by activating a solenoid, locking in a pulley connected to the drive chain and pulling the derailleur mechanism up or down. The handlebar-mounted control panel contained an LCD (Liquid Crystal Display), giving a visual indication of the current gear selection. The third unit, measuring speed, also transmitted data back to the control unit for display on the LCD.

Impact: The completed device operated within the specifications and provided a marked improvement over existing products. The total cost of bringing the project to the prototype stage was 34K Euros, whilst the projected payback period for the project was 10 months, with a return of investment of 350% over 2 years.