172 lines
5.9 KiB
Markdown
172 lines
5.9 KiB
Markdown
Contiki REST/CoAP Quickstart using Econotags
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======================================
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Contiki has an implementation of the IETF CORE (Constrained RESTful
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Environments) working group's CoAP layer (Constrained Application
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Protocol). CoAP is a RESTful application layer that uses HTTP-like
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methods (GET, POST, PUT, DELETE) to interact with constrained
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networks. CoAP operates over UDP and supports reliable transmission.
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This tutorial will show you how to run Contiki's CoAP demo on Redwire
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Econotags using an RPL border-router.
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1) Run a RPL border-router and tunnel
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---------------------------------------------------------------
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See [the RPL
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HOWTO](http://mc1322x.devl.org/repos/contiki-mc1322x/cpu/mc1322x/doc/rpl-tutorial.md)
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for details about running a RPL border-router.
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2) Build and run the `rest-server-example` on a second Econotag
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----------------------------------------
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__The following must be done on the contiki-mc1322x.git tree__
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git clone git://git.devl.org/git/malvira/contiki-mc1322x.git
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__Contiki CVS is currently down and the new SCM system hasn't been set
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up yet. The necessary changes will be pushed as soon as the new SCM is
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available. - 6 Februrary 2011__
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To build the rest-server-example:
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cd contiki-mc1322x/examples/rest-example
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make TARGET=redbee-econotag
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This will produce the binary image
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`rest-server-example_redbee-econotag.bin`, which you can load directly
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on to an mc1322x and execute.
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mc1322x-load.pl -f rest-server-example_redbee-econotag.bin -t /dev/ttyUSB3
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Then press the reset button to connect to the bootloader.
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In this example, we are loading the CoAP server on to the econotag on `/dev/ttyUSB3`
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You should see boot up messages similar to this:
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CONNECT
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Size: 62096 bytes
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Sending rest-server-example_redbee-econotag.bin
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done sending files.
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performing ring osc cal
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crm_status: 0xc0000
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sys_cntl: 0x18
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ring osc cal complete
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cal_count: 0x17e17e0
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cal factor: 100
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hib_wake_secs: 2000
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loading rime address from flash.
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Rime started with address 00:50:C2:AB:C0:00:00:23
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nullmac nullrdc, channel check rate 100 Hz, radio channel 26
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Tentative link-local IPv6 address
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fe80:0000:0000:0000:0250:c2ab:c000:0023
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Tentative global IPv6 address aaaa:0000:0000:0000:0250:c2ab:c000:0023
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Starting 'Rest Server Example'
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COAP Server
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The last line indicates that the server will be using
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COAP. As an alternative, you can build the server to use HTTP instead with:
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make TARGET=redbee-econotag WITH_COAP=0
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3) Download and install the `Copper` Firefox Plugin
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-----------------------------------------------------
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The `Copper` Plugin for Firefox provides the `coap:` URL access method
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as well as an interface to easily send `coap` requests.
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Download and install the plugin from here:
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+ [Copper plugin homepage](http://people.inf.ethz.ch/~mkovatsc/)
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+ Install link:[copper-0.3.0pre2.xpi](http://people.inf.ethz.ch/~mkovatsc/resources/copper/copper-0.3.0pre2.xpi)
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4) Open Copper
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--------------
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Open a new Firefox tab and click on the orange CU button in the lower
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right.
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[](http://mc1322x.devl.org/files/coap-blanktab.png)
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The initial CU screen will look like this:
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[](http://mc1322x.devl.org/files/coap-opencu.png)
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Type in the the URL of the coap node with the default port number of
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"61616":
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[](http://mc1322x.devl.org/files/coap-url.png)
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+ Don't forget the brackets ( [ ] ) in the URL
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+ Make sure to use the IPv6 address of your coap server. You can get
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this from the boot up messages or from the webpage served by your
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border-router.
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+ You must always press Enter after changing the URL.
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5) GET `.well-known/core` resources
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------------------------------------
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Now click on the red "./well-known/core" button: this changes the URL
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to the `.well-known/core` resource.
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Then click GET to perform a get. You should see an acknowledgement
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that the GET was successful (returns 200 OK). The payload should
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return:
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</helloworld>;n="HelloWorld",</led>;n="LedControl",</light>;n="Light
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Which is are the well-known resources that this node advertises; see
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the [COAP
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specification](https://datatracker.ietf.org/doc/draft-ietf-core-coap/)
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for details.
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[](http://mc1322x.devl.org/files/coap-wellknown.png)
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6) PUT,POST the `led` resource state
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------------------------------------
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You can PUT or POST to change the state of the LED.
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Type in the following URL and press enter:
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coap://[aaaa::250:c2ff:fea8:c48e]:61616/led?color=green
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Be sure to use the proper IP address. For this URL: we will perform
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actions on the `led` resource with a query string of `color=green`.
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In the payload, type:
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mode=on
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That is the payload that will be PUT or POSTed. The COAP server
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detects the mode string and activates the LED accordingly (with the
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color chosen by the query string).
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Then click PUT or POST to perform the request.
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[](http://mc1322x.devl.org/files/coap-led.png)
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You should get a successful return code (200 OK) and the green LED
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should turn on. If you PUT/POST `mode=off` the led will turn off.
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The econotag only has two LEDs: a green and a red. The red LED is used
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to indicate radio transmission by default and so cannot be used in
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this demo. The Coniki blue LED is connected to GPIO 43. You can toggle
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it, but you won't see anything unless you hook something up to this
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pin.
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7) Other resources
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------------------
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The `rest-server-example` also provides `helloworld` and `light` as
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GETtable resources.
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coap://[aaaa::250:c2ff:fea8:c48e]:61616/helloworld
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coap://[aaaa::250:c2ff:fea8:c48e]:61616/light
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The econotag does not have a light sensor. The light resource will
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always return 0. At a latter date, this sensor will be connected to
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one of the ADC pins.
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