TinyOS Lesson 6 Topology Control

Size: px

Start display at page:

Download "TinyOS Lesson 6 Topology Control"

Emory Daniel
6 years ago
Views:

1 TinyOS Lesson 6 Topology Control Object To learn how to adjust the power level when sending the data, and retrieve the RSSI and LQI values from the receiver. Use the program named RssiSend to transmit packets, and retrieve the RSSI and LQI values with BaseStation introduced in last lesson. Environment Setting Upgrade : NesC, tinyos-tools and TinyOS. Package Version needed Download NesC /tinyos/windows/nesc cygwin.i386.rpm tinyos-tools /tinyos/windows/tinyos tools cygwin.i386.rpm TinyOS /tinyos/windows/tinyos cygwin.noarch.rpm Use the command rpm Uvh to install them in Cygwin. Steps 1. Modify the program BlinkToRadio to RssiSend. Modify its data structure to record the values of power, rssi and lqi. typedef nx_struct DATA_MSG { nx_uint16_t nodeid; nx_uint8_t power; nx_int8_t rssi; nx_uint8_t lqi; DATA_MSG; 2. Define the value of transmitting power. The value ranges from 0 to 31. enum { AM_DATA_MSG = 3, TIMER_PERIOD_MILLI = 500, SET_POWER = 31 ; 3. The main difference between them is the interface CC2420Packet. Wire this interface to the component CC2420ActiveMessageC, because this component has implemented the interface CC2420Packet.

2 uses interface CC2420Packet; components CC2420ActiveMessageC; App.CC2420Packet > CC2420ActiveMessageC; 4. When transmitting packets, you could add the following command to set the value of transmitting power. Don t forget that you have already assigned this value in the header file. call CC2420Packet.setPower(&pkt,SET_POWER); 5. And then, we modify BaseStation to measure the values of RSSI and LQI. In the same way, wire the interface CC2420Packet to the component CC2420ActiveMessageC. 6. Add a new file named BaseStation.h under the directory BaseStation. The content of BaseStation.h should be the same as RssiSend.h in order to modify the packets with the same format. 7. When receiving packets in BaseStation, add the following lines to measure the values of RSSI and LQI. msg is the packet received. Modify its content and forward to UART. btrpkt >rssi = call CC2420Packet.getRssi(msg); btrpkt >lqi = call CC2420Packet.getLqi(msg); 8. Place the sensors as shown below. Listen the packets from BaseStation by UART in Cygwin. Observe the varying values of RSSI and LQI by changing the transmitting power or the distance between BaseStation and RssiSend. BaseStation RssiSend

9. Let the packets received more readable by the tool MIG (Message Interface Generator). You can use the MIG tool to build a Java, Python, or C interface to the message structure.

3 9. Let the packets received more readable by the tool MIG (Message Interface Generator). You can use the MIG tool to build a Java, Python, or C interface to the message structure. Given a sequence of bytes, the MIG generated code will automatically parse each of the fields in the packet, and it provides a set of standard accessors and mutators for printing out received packets or generating new ones. First, you have to check BaseStation.h. If the structure name of the packets is defined as DATA_MSG, then the existence of AM_DATA_MSG is essential to define the value of AM packets type. In that way, MIG can read BaseStation.h correctly. #ifndef BASESTATION_H #define BASESTATION_H enum { AM_DATA_MSG = 3, TIMER_PERIOD_MILLI = 500, ; typedef nx_struct DATA_MSG { nx_uint16_t nodeid; nx_uint8_t power; nx_int8_t rssi; nx_uint8_t lqi; DATA_MSG; #endif 10. Execute the following commands in Cygwin: mig java target=null java classname=rssisendmsg BaseStation.h DATA_MSG o RssiSendMsg.java

4 BaseStation.h:the file which define the packets DATA_MSG:the structure name of the packets RssiSendMsg:the name of java class RssiSendMsg.java:the name of the output file, usually it is same as RssiSendMsg 11. If there is no errors after executing commands above, see the file RssiSendMsg.java, there are many useful functions generated automatically. public short get_power() { return (short)getuintbeelement(offsetbits_power(), 8); public byte get_rssi() { return (byte)getsintbeelement(offsetbits_rssi(), 8); public short get_lqi() { return (short)getuintbeelement(offsetbits_lqi(), 8); 12. Design Demo.java to read the packets with the functions that MIG generate. public Demo(MoteIF moteif) { this.moteif = moteif; this.moteif.registerlistener(new RssiSendMsg(), this); public void messagereceived(int to, Message message) { RssiSendMsg msg = (RssiSendMsg) message; int source = message.getserialpacket().get_header_src(); System.out.println("Node " + source + ": Power= " + msg.get_power() + ": Rssi= " + msg.get_rssi() + ": Lqi= " + msg.get_lqi()); 13. Compile these file in Cygwin. javac RssiSendMsg.java javac Demo.java Results Execute Demo to listen the packets from BaseStation. java Demo

ANEXO D CÓDIGO DE LA APLICACIÓN. El contenido de los archivos de código fuente almacenados en el directorio Nodo desconocido es el siguiente:

ANEXO D CÓDIGO DE LA APLICACIÓN El contenido de los archivos de código fuente almacenados en el directorio Nodo desconocido es el siguiente: APPLICATIONDEFINITIONS.H #ifndef APPLICATIONDEFINITIONS_H #define