Intelligenta Switchar

Sammanfattning

This master thesis has been carried out on behalf of Stoneridge Electronics AB and is an investigation of

how intelligent switches can replace the traditionally used direct controlled switches. The concept of

intelligent switches is that the switches contain electronic identification components which, by connecting

them to a network, give the same function independent of the location of the switch. This infers an

increased flexibility and configurability which can be a great advantage in development, production and

customization in the commercial vehicle industry. Especially in the current situation when commercial

vehicle manufacturers provides more and more functions and dashboard configurations.

LIN (Local Interconnect Network) is a network protocol introduced in 1999. It is a simpler and lower cost

complement to CAN (Controller Area Network) and is adapted for applications where the demands for

bandwidth are lower, for example reading sensors and switchers. This made LIN a natural network choice

for this thesis and the investigation could focus on switch identification methods. Two identification

methods are presented in this thesis, resistance encoding and 1-Wire. They are investigated and discussed

on the basis of a set of predetermined demands such as response time and the amount of unique switches

the method can distinguish.

The practical part of this thesis include the design of a prototype which main purpose is to act as a

demonstration platform for intelligent switches but also for technique evaluation i.e. serve as a base for

response time measurements. The prototype is based on a LIN network with three nodes and the

identification method used is resistance encoding. In resistance encoding every switch is provided with a

unique resistance and the switches position and status are identified with AD-conversion.