Tutorial:ZigBee

This page shows the tutorial for experiments with ZigBee communications and the testbed.

The ZigBee Testbed in B1-612, Main Building

Useful links:

• TinyOS intro (Chinese)
• Programming model of TinyOS (Chinese)
• TinyOS main site and official tutorials

The simplest example

This example shows

1) how the event-driven programming works,

2) how to burn a program to a TelosB node.

for details you can see simplest tinyos program

---

1. Configuration file, SimpleAppC.nc

configuration SimpleAppC{
}

implementation{ 
    components SimpleC, MainC;
    SimpleC.Boot -> MainC.Boot;
}

this file will link two components SimpleC and MainC

2. SimpleC.nc

module SimpleC{
    uses interface Boot;
}

implementation{
    event void Boot.booted() {
    }
}

When system starts, it will call interface booted in MainC, but this interface is not implemented.

So SimpleC implements it.

MainC in nesC is just like main function in C.

In this example, it does nothing, so it is just like following code in C:

int main () {
  return 0;
}

3. Makefile

COMPONENT=SimpleAppC
include $(MAKERULES)

with Makefile we can compile the code by typing

make telosb

4. install

make telosb install bsl,/dev/ttyUSB0

Measurement

To measure various information from received packets.

Details is here

Code template

ExampleC.nc

// extract info upon receiving a packet.
event message_t* Receive.receive(message_t* bufPtr, void* payload, uint8_t len) {
    if (len != sizeof(msg_t)) {
        return bufPtr;
    } else {
        msg_t* msg = (msg_t*)payload;
        // msg is the info, we can do something upon it.
        // write your code with msg here, for example, we show it by led
        call Leds.set(msg->counter);
        return bufPtr;
    }
}

Payload

ExampleC.nc

// following code is the implementation
// to send a packet, we should create a packet at first.
message_t packet; // packet is a container of payload.
bool locked; // when it is sending a packet, sender is locked.
uint16_t counter = 0; // the payload in this example

event void Timer0.fired() {
    msg_t *msg;
    // important!!!
    // variable declaration must be present before operation
    // in this example, msg is present before `if (locked)'
    if (locked) {
        return;
    }
    msg = (msg_t*) call Packet.getPayload(&packet, sizeof(msg_t));
    ++counter;
    // suppose msg contains payload `counter`
    msg->counter = counter;
    // if there is other payload in msg, do assignment.
    // to send this packet
    if (call AMSend.send(AM_BROADCAST_ADDR, &packet, sizeof(msg_t)) == SUCCESS) {
        locked = TRUE;
        // the packet is being sent
    }
}

Header

ExampleC.h

#ifndef EXAMPLE_H
#define EXAMPLE_H

typedef nx_struct example_msg {
  nx_uint16_t counter;
} msg_t;

enum {
    AM_MSG = 6, // mesage group
};
#endif

ExampleAppC.nc

#include "Example.h"
configuration ExampleAppC {}
implementation {
    components MainC, ExampleC as App, LedsC;
    components new AMSenderC(AM_MSG);
    components new AMReceiverC(AM_MSG);
    components new TimerMilliC() as Timer0;
    components ActiveMessageC;
  
    App.Boot -> MainC.Boot;
  
    App.Receive -> AMReceiverC;
    App.AMSend -> AMSenderC;
    App.AMControl -> ActiveMessageC;
    App.Leds -> LedsC;
    App.Timer0 -> Timer0;
    App.Packet -> AMSenderC;
}

ExampleC.nc

#include "Timer.h"
#include "Example.h"
module ExampleC @safe() {
    uses {
        interface Leds;
        interface Boot;
        interface Receive;
        interface AMSend;
        interface Timer<TMilli> as Timer0;
        interface SplitControl as AMControl;
        interface Packet;
    }
}
implementation {
    event void Boot.booted() {
        call AMControl.start();
    }

    event void AMControl.startDone(error_t err) {
        if (err == SUCCESS) {
            call Timer0.startPeriodic(250);
        } else {
            call AMControl.start();
        }
    }
    // ... see in other sections: code example, payload
}

Footer

ExampleC.nc

// to unlock
event void AMSend.sendDone(message_t* bufPtr, error_t error) {
    if (&packet == bufPtr) {
        locked = FALSE;
    }
}
event void AMControl.stopDone(error_t err) {
     // do nothing
}

Makefile

COMPONENT=ExampleAppC
include $(MAKERULES)

Routing

Code template

we can change ADDRESS to implement different protocols.

if (call AMSend.send(ADDRESS, &packet, sizeof(msg_t)) == SUCCESS) {
    locked = TRUE;
    // the packet is being sent
}

Broadcast

AM_BROADCAST_ADDR is a MACRO. Using this ADDRESS, a mote will boradcast the packet.

AM_BROADCAST_ADDR

Unicast

When load the binary to the mote, we can set the TOS_NODE_ID, so we can set the ADDRESS to a specific TOS_NODE_ID, such as 1 to unicast a packet. For exmaple, if we want to set TOS_NODE_ID = 1 in /dev/ttyUSB2

make telosb install,1 bsl,/dev/ttyUSB2

Testbed usage

Data collection using USB cables

Details is here.

Useful parse scripts

1. bitmap.py

Say mote A sends 1000 packets, numbered from 1 ~ 1000, then we want to know how many packets mote B receives, and what there numbers are.

A bitmap is like "001100101010...", where "0" means B does not receive the packet and "1" means B receives the packet.

#!/usr/bin/env python
def raw2bit(src_file, dest_file, total_bit):
    """
    @brief      get bitmap from raw data
    
    @param      src_file   The source file path (raw data generated by tinyos printf function)
    @param      dest_file  The destination file path (bitmap file as output)
    @param      total_bit  The total bits of the package (size of bitmap)
    
    @return
    """
    with open(src_file,'rb') as fr:
        fw = open(dest_file,'w')
        line_1 = fr.readline().strip()#除去换行符号'\n'
        receive = 0 #总的收包个数
        count = 1   #上一个收到的包的序列号加1
        if len(line_1) < 24:
            pass    #第一行的固定前缀有23个字符
        else:
            start = int(line_1[23:])
            for i in range(start - 1):
                fw.write('0')
            fw.write('1')
            receive += 1
            count = start + 1
        for line in fr:
            for j in range(int(line) - count):
                fw.write('0')
            fw.write('1')
            receive += 1
            count = int(line) + 1
        for k in range(total_bit - count + 1):
            fw.write('0')
        fw.close()
    fr.close()