The Design and Implementation of Campus Card in the Shower System

The Design and Implementation of Campus Card in the Shower

System

Abstracts： This paper analyzes the application

characteristics of campus smart card and electronic account，

from the students requirements of shower management， made

some research and Study on the campus smart card electronic

account application and the CAN bus data transmission and

developed a general admission fee based on network of campus

card and CAN bus communication system， realize no cash

operation in the finance charge project. This paper is discussed

in detail from the communications and design payment system，

interface， security aspects， and provides a reference of smart

card application for the similar colleges.

Keywords： Campus card； electronic account； CAN bus；Campus card； Shower system

0 Introductions

Construction and application of campus card system

manifests digitalization， informatization level of campus. At

present， smart card have been applied and development in

colleges and universities. The campus smart card has authentication and consumption of the two major functions，

that is widely used in the dining hall， apartments hydropower，

library management， computer management， access control

attendance， health care， supermarket， stadiums， parks

transit system experiment. Along with the card function

continuously upgrade and expand scale， it makes campus card

system has been popularized and widely used. More and more

colleges and universities have used the campus card system，

which provides convenience for the management of the school.

The controller area network （CAN） is design by German

Bosch Company as a serial communication bus between the

developments of electronic control device for many in the

modern automotive industry data [1]. As one of the most widely

used field bus internationally， the bit rate of CAN have high，

high anti-interference， signal transmission distance to 10km，

still can provide data transmission rate up to 5kbps [2]. Because

CAN has these characteristics， it has been widely used in

industrial control， intelligent building， medical equipment and

automotive electronics systems and many other fields [1].

The communication characteristics of campus smart card

system are very suitable for use CAN， as shown in the

following two aspects： （1） The campus card system need high performance

requirements of anti-jamming performance and real-time

communication， and the single communication volume is

small， short frame structure for CAN.

（2） The campus card system outlets are numerous and

dispersed， and the characteristics of CAN network flexibility

can solve these problems. If the network with the CAN

repeater mode， the terminal equipment to address additional

frame in CAN ID， however， CAN frame ID not used as

terminal equipment identifier， and CAN abolished the principle

which station address coding， limited terminal equipment

capacity， did not make full use of the existing Ethernet campus

resources， not suitable for the trend of integration a large

campus information， but very suitable for student hostel

shower control charging system.

1 The network topology

If the consumer subsystem directly adopts Ethernet

network， application layer data of consumption terminal will

be through the TCP/IP protocol stack package， while the

consumer terminal has a high requirement for real-time

communication performance.

The minimum length of the Ethernet frame is 64 bytes； remove the Ethernet header and TCP/IP header of 18 bytes 40

bytes， 6 bytes are also used for storing the application layer

data. In contrast， CAN maximum frame is 16 bytes， which

contains 8 bytes of application layer data. The control

information of the Ethernet frame containing too much， while

the consumer terminal single traffic is small.

Therefore， for the characteristics of the communication

subsystem to expand consumption， terminal equipment

capacity， make full use of campus Ethernet resources， give

full play to the advantages of Ethernet in the wireless extension，

consumer， networking subsystem uses a combination of CAN

and Ethernet， network structure as shown in Figure 1， figure

2 shows the advantages of CAN and Ethernet fusion.

2 The design of CAN intelligent node

Using MCP2510 and CAN bus transceiver TJA1050 can

form a CAN bus distributed measurement and control network.

The system comprises a main controller and a plurality of node

controller， this controller can monitor current， voltage and the

surrounding the motor temperature， its structure as shown in

figure 3.

The network topology used bus structure and passive tap