Wireless Bike Rear Derailleur System
Mixed signal ASIC technology results in innovative new product
Technologies used

Mixed signal ASIC

Industrial sector (PRODCOM code)
    35 Transport equipment
Established in 1890, MAVIC designs, manufactures and markets high quality equipment and accessories for high value mountain and road racing bikes including rims, wheels, hub with cartridge bearings and the electronic derailleur. Products are distributed to end users via a network of sales distributors world-wide. The company employs 300 people, and has sales turnover of 35 M Euros. The majority of MAVIC's product range was based on the design, development and production of bicycle mechanical components. In 1993, MAVIC introduced the "ZAP MAVIC SYSTEM" (ZMS), an electronically controlled derailleur, which enabled push button instigation of up or down gear shifting on bicycles. This micro-controller based product was developed by subcontractors, and this was MAVIC's first electronic experience. The ZMS product was a market success, but was withdrawn from the market by the company in 1995 because of reliability problems associated with the wired solution. The strong market response indicated that a product which provided a method of communications which overcame the reliability problems associated with the wiring would be a major economic success. This market opportunity led MAVIC to develop a mixed signal ASIC device to implement a bi-directional, wire-less, digital communication link between the rear derailleur and a controller on the handle bar to overcome these reliability problems. These two units are set approximately 1.2 m apart on the bicycle, and form part of an overall system including brake levers with an embedded gear switch and a front wheel wireless speed sensor. The system uses 3 printed circuit boards (PCBs) Each PCB contains two IC components: 1. A specific micro-controller with the signal processing software of the wireless transmission and the specific control functions for the device it controls. 2. The mixed signal ASIC which is controlled by the micro-controller. Each circuit is in standby mode most of the time to minimise consumption, switches periodically to detection mode to check whether incoming messages are being sent and, if so, switches to full receiving mode. The improved system provides the cyclist with several benefits including:
· Quick gear shift operation.
· Short assembly time, based on ease of mounting of the system components.
· Speed indication on system display.
· Compatibility with all cycle frame sizes.
· User feedback via visual presentation of gear position on the control and display module's LCD display
The mixed signal ASIC development was completed within 12 months. The ASIC development costs were 138 k Euros. Based on the total system development costs which included a significant industrialisation cost, payback period is estimated to be less than 10 months and ROI in 2001 will be 350%. Based on mixed signal ASIC development costs alone, these figures become respectively less than 1 month and 3500%.

Detailed information

You can also benefit from microelectronics

Mixed signal ASIC technology provided MAVIC with the means of improving its products and enhancing its market position. You can also achieve significant benefits by acquiring the right microelectronics technology and utilising it in your product or manufacturing process. You can get help from FUSE to realise this.

FUSE is a technology transfer programme, funded by the European Commission to stimulate the wider use of microelectronics technologies by European enterprises to increase their competitiveness and enhance their economic growth. The demonstrator described here is one of many examples in the public FUSE portfolio covering the whole spectrum of microelectronics technologies and spanning a wide range of applications and industry sectors.

FUSE provides you with:

  • Best practice in acquiring specific microelectronics technologies and conducting full development projects through the FUSE portfolio of real life demonstrator documents.
  • Local training and expert support to plan your innovation realistically and help you conduct your project successfully.

Further information and support relating to this and other demonstrators can be obtained from the addresses below.

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