Thermostat Example Application

Table of Contents

• Introduction
• Hardware Prerequisites
• Software Prerequisites
• Functional Description
• Software Overview
  • Application Files
  • Example Application
• Usage
• Buttons
• Display
• Setting up the Thread Network
• Interfacing with the Example Application

Introduction

This document discusses how to use the Thermostat Example Application and the different parts that compose it. Thermostat Example Application is a standalone CoAP server example running on Thread.

Some of the areas explored are:

• Setting up a network.

• Bringing up the device as a Full Thread Device(FTD).

• Initialization and use of the Constrained Application Protocol (CoAP) APIs.

Hardware Prerequisites

• 2 x CC2652 LaunchPads

• (optional) 1 x Sharp96 LCD boosterpack.

Software Prerequisites

• Code Composer Studio(CCS) v7.3 or higher

Functional Description

Software Overview

This section describes software components and the corresponding source file.

Application Files

• thermostat.[ch]: Contains the application’s event loop, CoAP callback functions, device initialization function calls, and all thermostat specific logic.

• otstack.[ch]: OpenThread stack processing, instantiation and network parameters.

• task_config.h: This file contains the definitions of the RTOS task priorities and stack sizes.

• images.[ch]: Contains the raw binary of the images being displayed on the LCD screen.

If the application is compiled with the predefined symbol, ALLOW_PRECOMMISSIONED_NETWORK_JOIN, following parameter should be verified in otstack.h.

• OT_NWK_PAN_ID This is the Personal Area Network (PAN) identifier of the network. The default value is set to 0xface. Please make sure this matches the PAN ID set in the border router, otherwise change it accordingly.

• OT_NWK_CHANNEL This sets the channel on which the device will be operating in the 2.4 GHz spectrum as per the IEEE 802.15.4 specification. The default value is channel 14.

Example Application

This application provides an example implementation of a thermostat using the Thread wireless protocol and CoAP as the application layer protocol. The thermostat application is configured as a full thread Device (FTD) which supports CoAP commands to control the temperature and setpoint. These are integers in the range of [10 .. 99].

Usage

This section describes how to set up and run the Thermostat Example Application.

Buttons

• BTN-1 + BTN-2 at boot: A factory reset of the non-volatile storage is performed. This must be pressed at the start of the OtStack_task function.

• BTN-2: Start the joining process. This may be pressed after the hold image appears on-screen.

Display

There are 2 ways that this application will display information to the user which can be used simultaneously and are described below:

1. Serial terminal: The thermostat events will be displayed through UART to a serial terminal emulator. To enable the serial terminal in CCS press `ctrl

• shift + alt + T, selectSerial TerminalunderChoose terminal, select115200for Baud Rate and clickOK`

1. Sharp96 LCD boosterpack: There is no extra configuration needed to use the LCD boosterpack other than plugging it to the LaunchPads running the example application.

Setting up the Thread Network

This section describes how to set up a Thread network. The application supports the ability to be commissioned into a Thread network. Commissioning may be bypassed by compiling with the ALLOW_PRECOMMISSIONED_NETWORK_JOIN predefined symbol. The Temperature Sensor example has the ability to report to the Thermostat, consult its README for details on this functionality.

1. Set up a LaunchPad as a CLI FTD device by following the READMEs files in the respective application folder.

2. Load and run the Thermostat example on a second LaunchPad.

3. The Thermostat will print out the device’s EUI64 and the application’s PSKd (pre-shared key device identifier) over the UART terminal. If the device was not already commissioned or was built without the ALLOW_PRECOMMISSIONED_NETWORK_JOIN symbol, it will display this information on the LCD screen. If the device has already been commissioned, skip to step 8.

pskd: THERMSTAT1 EUI64: 0x00124b000f6e6113

1. Start a commissioner on the CLI FTD by issuing the following command. commissioner start It will display Done if it is successful in starting the network.

2. Add Thermostat LaunchPad device as a joiner device by providing the EUI64 and pskd as credentials to the commissioner. commissioner joiner add 00124b000f6e6113 THERMSTAT1 It will display Done if it is successful in adding the joiner entry.

3. Now on the Thermostat LaunchPad, press BTN-2 to start the joining process. The display will show Joining Nwk ....

4. Once the joining process has successfully completed, the LCD will display Joined Nwk before switching to the thermostat image. The green LED should turn on on the shade LaunchPad once it has joined the network.

5. Next we need to get the IPv6 address of the thermostat LaunchPad. Use the command ping ff03::1 to send an ICMP echo request to the realm-local all nodes multicast address. All devices on Thread network will respond with an ICMP echo response. You will see in the terminal a response like the one below.

8 bytes from fd00:db7:0:0:0:ff:fe00:b401: icmp_seq=1 hlim=64 time=11ms

Interfacing with the Thermostat Example Application

The thermostat application hosts a simple CoAP server with two registered resources for the current temperature and setpoint. These resources support CoAP GET and POST commands. Any device with scope of the thermostat’s IPv6 address send commands to the thermostat application.

Thermostat Attribute URI:

• Temperature value: thermostat/temperature

• Temperature setpoint: thermostat/setpoint

Open up the serial terminal to the cli_ftd application and also to the thermostat application.

Starting the CoAP client

In the CLI FTD serial terminal, type coap start at the prompt to start the CoAP service. It will display the following message if it successful in starting the CoAP service. Coap service started: Done

Getting status from the Thermostat

To get the thermostat’s current temperature, type the following command into the CLI FTD terminal.

coap get fd00:db7:0:0:0:ff:fe00:b401 thermostat/temperature

NOTE: The IPv6 address will be different for your setup

The thermostat should respond, and the cli_ftd will print a message like the following.

Received coap response with payload: 3635

Converting the payload from hex to ascii we get 65 which is the default temperature in degrees Fahrnenheit.

The above process can be repeated with the endpoint thermostat/setpoint in place of thermostat/temperature to get the current setpoint.

Controlling the Thermostat

The thermostat temperature can be changed by sending the appropriate payload in a CoAP confirmable (con) POST command message, to the IPv6 address of the thermostat and the resource URI attribute.

Use the following command in the CLI FTD terminal to set the thermostat’s temperature to 90 degrees Fahrenheit.

coap post fd00:db7:0:0:0:ff:fe00:b401 thermostat/temperature con 90

NOTE: The IPv6 address will be different for your setup

The initial command will result in the message Sending coap request: Done. The thermostat will respond, and the CLI FTD will print the following message.

Received coap response with payload: 3930

If the POST was successful, the thermostat will change the image displayed on the LCD boosterpack and print its state change over the serial port.

The above process can be repeated with the endpoint thermostat/setpoint to change the current setpoint of the thermostat.