Tag Archives: Wio Node

Matters relating to the Wio Node Internet of Things hardware platform from Seeed Studio

Node-RED and the Internet of Things

Here at Cranfield University we are putting in place plans related to the new ‘Living Laboratory’ project, part of our ‘Urban Observatory’. This project sits within the wider UKCRIC initiative, across a number of universities. Of the many experiments in development, we are gathering environmental data from IoT devices and building data dashboards to show the data and related analyses.

In this blog we investigate the use of Node-RED (https://nodered.org) as a programming tool for wiring together hardware devices, APIs and online services, using its browser-based editor to wire together flows using the wide range of nodes in the palette that can be deployed to its runtime in a single-click. Node-RED provides graphical programming tool for Node-JS that permits complex programs to be built pictorially with great ease. To undertake the project, we used a WIO Node device collecting temperature values, exposing these values via a web service, and the Node-RED receiving device being a Raspberry Pi.

Sourcing temperature data – the Wio Node

The Wio Node temperature sensor was described in an earlier blog here (http://www.geothread.net/voice-activated-wio-node-temperature-sensor). Temperature values are extracted via a web-based API call, with the REST URL taking the form, thus:


The temperature values are then returned as a JSON string, appearing thus:


Preparing the Raspberry Pi – installing Node-RED

To prepare the Raspberry Pi and install Node-RED, we first followed instructions to install Node-JS on the Pi at https://www.w3schools.com/nodejs/nodejs_raspberrypi.asp. Next we followed the instructions on the Node-RED site (https://nodered.org/docs/hardware/raspberrypi). In brief, we ran the Node-RED upgrade script:

bash <(curl -sL https://raw.githubusercontent.com/node-red/raspbian-deb-package/master/resources/update-nodejs-and-nodered)

We then set Node-RED to start automatically on boot, with:

sudo systemctl enable nodered.service

Running Node-RED

The Raspberry Pi was then rebooted. We were then able to start using the Node-RED editor (https://nodered.org/docs/hardware/raspberrypi#using-the-editor), calling the web-based interface with the URL (the IP address being that if the Raspberry Pi):


The general Node-RED interface, ‘palette’ to the left, properties to the right, and design canvas centrally.

Node-RED allows installation of many modules, one of which permits data dashboards. The data dashboard module is described at https://flows.nodered.org/node/node-red-dashboard. Installation can be via npm, as described at the link above. However, we used the ‘Manage Palette’ option within the graphical interface to install the new functions.

With this installed, the next task was to develop the ‘flow’, or programme. This starts with a HTTP GET call to the WIO Node as described above. For this the ‘http request’ node is called, and configured with the URI to the temperature value. After consideration of the various configuration options, we elected to return a ‘parsed JSON object’.

To drive the process whereby the URI is called continuously, the http request call is preceded with an ‘inject node’, set to run continuously on a timed basis (shown here at 5 seconds, although that could be a longer period).

The data that is returned from this process, the ‘payload’, can now be passed directly to the first element of the dashboard – the gauge. The payload JSON object has a member ‘temperature’, referenced via the value format {{payload.temperature}}.

The next dashboard elements we wanted are firstly a line graph of temperature over time, and secondly a custom node recording the ‘minimum’ and ‘maximum’ temperatures over time. These nodes will need data prepared in a particular way. The graph, or chart, needs data in the form described at https://github.com/node-red/node-red-dashboard/blob/master/Charts.md.

{topic:"temperature", payload:22}

In addition, further JSON elements for minimum and maximum values will be required. In order to construct a revised message payload, a custom script is required. Explanations are in the code below:

// Create a new empty object 'newMsg' to return at the end
// then fill it with another empty object 'bounds'
var newMsg={bounds:{}}; // create

// Create two local variables min and max initialised from the persistent 
// context variables of the same names where these values exist, or else
// seed with values we know are off the scale
var min=context.get('min') || 100;
var max=context.get('max') || -100;

// Set an element 'topic' and give the value the string 'temperature'
newMsg.topic = 'temperature';
// Set the payload element to the incoming message payload temperature
newMsg.payload = msg.payload.temperature

// update the min and max, comparing the incoming values to the context
if (msg.payload.temperature < min) {
   newMsg.bounds.min = msg.payload.temperature;
   context.set('min', msg.payload.temperature);
} else {
   newMsg.bounds.min = min;
if (msg.payload.temperature > max) {
   newMsg.bounds.max = msg.payload.temperature;
   context.set('max', msg.payload.temperature);
} else {
   newMsg.bounds.max = max;

// and finally return the new object 'newMsg'
return newMsg;

What is always a good idea when processing data is to have a debug that shows the whole message object constructed by this process. To do this, a ‘debug node’ is added and configured – here to show the ‘complete msg object’. We can see the min and max are contained in the bounds node, and that the ‘topic’ and ‘payload’ elements are correctly configured.

As a result, the two additional dashboard node widgets can be added, first the chart node. The line interpolation is set here to ‘bezier’ to provide a smoother visualisation. The time interval is set to 15 minutes.

Next we wanted to add a new custom node widget to show a running maximum and minimum value. To do this, we added a ‘Template node’ and configured it thus:

<div layout="row" layout-align="start center">
  <span flex>Temp Min: </span>
  <span flex>Temp Max: </span>
<div layout="row" layout-align="start center" ng-repeat="bounds in msg">
  <span flex style="color: green">{{bounds.min}}</span>
  <span flex style="color: red">{{bounds.max}}</span>

Once these elements are all in place, the ‘flow’ programme can be deployed. This commences the running of the code, and then the dashboard can be accessed. The easiest means to do this is to follow the link in the properties section as shown:

The result is the display of the dashboard. To get this to display as required, one can change the visual style (e.g. to ‘dark’), and the dimensions of the canvas. Node dashboard widgets are always rendered to the top left according to the layout properties.


In this blog, we have shown how the Node-RED environment can be used to streamline Node-JS code, with customised elements, and inclusion of libraries of functionality (dashboard). Node-RED is a powerful yet easy to configure environment that is cable of a whole range of functionality though its graphical ‘flows’. There are many example flows available on websites that can be downloaded and tested. Flows are designed to be easily imported and exported. Below is the export for the flow described above – to load it, select ‘Import’ and ‘Clipboard’ from the main menu options and paste in the following.

<div layout="row" layout-align="start center">[{"id":"d988539b.52bdc8","type":"tab","label":"Temperature","disabled":false,"info":""},{"id":"35963a2e.6aa056","type":"tab","label":"Temperature","disabled":false,"info":""},{"id":"166841a0.b19cce","type":"mqtt-broker","z":"","broker":"","port":"1883","clientid":"Teste","usetls":false,"compatmode":true,"keepalive":"60","cleansession":true,"birthTopic":"","birthQos":"0","birthPayload":"","willTopic":"","willQos":"0","willPayload":""},{"id":"a76a54d5.4c5998","type":"ui_tab","z":"d988539b.52bdc8","name":"ESP_DTH11","icon":"dashboard","order":3,"disabled":false,"hidden":false},{"id":"519167a8.570e5","type":"ui_group","z":"d988539b.52bdc8","name":"DHT11","tab":"a76a54d5.4c5998","order":1,"disp":true,"width":"12","collapse":false},{"id":"1785bc54.de4d24","type":"ui_base","theme":{"name":"theme-dark","lightTheme":{"default":"#0094CE","baseColor":"#0094CE","baseFont":"-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Oxygen-Sans,Ubuntu,Cantarell,Helvetica Neue,sans-serif","edited":true,"reset":false},"darkTheme":{"default":"#097479","baseColor":"#097479","baseFont":"-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Oxygen-Sans,Ubuntu,Cantarell,Helvetica Neue,sans-serif","edited":true,"reset":false},"customTheme":{"name":"Untitled Theme 1","default":"#4B7930","baseColor":"#4B7930","baseFont":"-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Oxygen-Sans,Ubuntu,Cantarell,Helvetica 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object","active":true,"tosidebar":true,"console":true,"tostatus":false,"complete":"true","targetType":"full","x":1129.75,"y":286.9166564941406,"wires":[]},{"id":"aa810265.1f789","type":"ui_gauge","z":"d988539b.52bdc8","name":"Gauge","group":"519167a8.570e5","order":0,"width":"6","height":"2","gtype":"gage","title":"Temperature","label":"Celsius","format":"{{payload.temperature}}","min":0,"max":"60","colors":["#00b500","#e6e600","#ca3838"],"seg1":"25","seg2":"28","x":1086.833251953125,"y":432.8055419921875,"wires":[]},{"id":"aa922201.f96eb8","type":"inject","z":"d988539b.52bdc8","name":"","topic":"","payload":"","payloadType":"date","repeat":"","crontab":"","once":true,"onceDelay":0.1,"x":401.5,"y":394,"wires":[["cbeca854.f6174"]]},{"id":"cbeca854.f6174","type":"http request","z":"d988539b.52bdc8","name":"Wio Temperature","method":"GET","ret":"obj","paytoqs":false,"url":"https://us.wio.seeed.io/v1/node/GroveTemp1WireD1/temp?access_token=7c6297dfa2e48793c58a53269bc23ef0","tls":"","proxy":"","authType":"basic","x":610.5,"y":394,"wires":[["aa810265.1f789","cd69dcd.1c5d3a"]]},{"id":"af52c259.fecbd8","type":"ui_chart","z":"d988539b.52bdc8","name":"Chart","group":"684a7caa.4db0f4","order":2,"width":"12","height":"7","label":"Temperature chart","chartType":"line","legend":"true","xformat":"HH:mm:ss","interpolate":"bezier","nodata":"","dot":false,"ymin":"","ymax":"","removeOlder":"15                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               ","removeOlderPoints":"50","removeOlderUnit":"60","cutout":0,"useOneColor":false,"colors":["#1f77b4","#aec7e8","#ff7f0e","#2ca02c","#98df8a","#d62728","#ff9896","#9467bd","#c5b0d5"],"useOldStyle":false,"outputs":1,"x":1087.8333740234375,"y":384.22222900390625,"wires":[[]]},{"id":"cd69dcd.1c5d3a","type":"function","z":"d988539b.52bdc8","name":"Process temperature","func":"var newMsg={bounds:{}};\nvar min=context.get('min') || 100;\nvar max=context.get('max') || -100;\n\n// http://www.steves-internet-guide.com/node-red-variables/\nnewMsg.topic = 'temperature';\nnewMsg.payload = msg.payload.temperature\n\nif (msg.payload.temperature &lt; min) {\n   newMsg.bounds.min = msg.payload.temperature;\n   context.set('min', msg.payload.temperature);\n} else {\n   newMsg.bounds.min = min;\n}\nif (msg.payload.temperature &gt; max) {\n   newMsg.bounds.max = msg.payload.temperature;\n   context.set('max', msg.payload.temperature);\n} else {\n   newMsg.bounds.max = max;\n}\n\nreturn newMsg;","outputs":1,"noerr":0,"x":875.5,"y":336,"wires":[["af52c259.fecbd8","a7d331dd.9d8078","81bda4f5.6f104"]]},{"id":"259fa218.53bdbe","type":"comment","z":"d988539b.52bdc8","name":"Useful links","info":"see:\nhttps://github.com/node-red/node-red-dashboard/blob/master/Charts.md\nhttp://noderedguide.com/tutorial-node-red-dashboards-multiple-lines-on-a-chart/#more-1612\nhttp://www.steves-internet-guide.com/node-red-functions/\nhttp://www.steves-internet-guide.com/node-red-dashboard/","x":400.5,"y":337,"wires":[]},{"id":"81bda4f5.6f104","type":"ui_template","z":"d988539b.52bdc8","group":"519167a8.570e5","name":"Max and Min","order":2,"width":"6","height":"2","format":"</p><div layout="\&quot;row\&quot;" layout-align="\&quot;start" center\"="">\n  <span flex="">Temp Min: </span>\n  <span flex="">Temp Max: </span>\n</div>
<p>\n</p><div layout="\&quot;row\&quot;" layout-align="\&quot;start" center\"="" ng-repeat="\&quot;bounds" in="" msg\"="">\n  <span flex="" style="\&quot;color:" green\"="">{{bounds.min}}</span>\n  <span flex="" style="\&quot;color:" red\"="">{{bounds.max}}</span>\n</div>
<p>\n","storeOutMessages":true,"fwdInMessages":true,"templateScope":"local","x":1109.4444122314453,"y":336.6666717529297,"wires":[[]]},{"id":"f5bb5785.45e55","type":"debug","z":"35963a2e.6aa056","name":"Message object","active":true,"tosidebar":true,"console":true,"tostatus":false,"complete":"true","targetType":"full","x":1129.75,"y":286.9166564941406,"wires":[]},{"id":"27187c33.85c07c","type":"ui_gauge","z":"35963a2e.6aa056","name":"Gauge","group":"c86b0ed1.65efc8","order":0,"width":"6","height":"2","gtype":"gage","title":"Temperature","label":"Celsius","format":"{{payload.temperature}}","min":0,"max":"60","colors":["#00b500","#e6e600","#ca3838"],"seg1":"25","seg2":"28","x":1086.833251953125,"y":432.8055419921875,"wires":[]},{"id":"cd94fffc.6f0da8","type":"inject","z":"35963a2e.6aa056","name":"","topic":"","payload":"","payloadType":"date","repeat":"","crontab":"","once":true,"onceDelay":0.1,"x":401.5,"y":394,"wires":[["ab8d1686.0264d"]]},{"id":"ab8d1686.0264d","type":"http request","z":"35963a2e.6aa056","name":"Wio Temperature","method":"GET","ret":"obj","paytoqs":false,"url":"https://us.wio.seeed.io/v1/node/GroveTemp1WireD1/temp?access_token=&lt;<your token="" here="">&gt;","tls":"","proxy":"","authType":"basic","x":610.5,"y":394,"wires":[["27187c33.85c07c","ce9f0009.faab98"]]},{"id":"dbe1013a.863be8","type":"ui_chart","z":"35963a2e.6aa056","name":"Chart","group":"684a7caa.4db0f4","order":2,"width":"12","height":"7","label":"Temperature chart","chartType":"line","legend":"true","xformat":"HH:mm:ss","interpolate":"bezier","nodata":"","dot":false,"ymin":"","ymax":"","removeOlder":"15                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               ","removeOlderPoints":"50","removeOlderUnit":"60","cutout":0,"useOneColor":false,"colors":["#1f77b4","#aec7e8","#ff7f0e","#2ca02c","#98df8a","#d62728","#ff9896","#9467bd","#c5b0d5"],"useOldStyle":false,"outputs":1,"x":1087.8333740234375,"y":384.22222900390625,"wires":[[]]},{"id":"ce9f0009.faab98","type":"function","z":"35963a2e.6aa056","name":"Process temperature","func":"var newMsg={bounds:{}};\nvar min=context.get('min') || 100;\nvar max=context.get('max') || -100;\n\nnewMsg.topic = 'temperature';\nnewMsg.payload = msg.payload.temperature\n\nif (msg.payload.temperature &lt; min) {\n   newMsg.bounds.min = msg.payload.temperature;\n   context.set('min', msg.payload.temperature);\n} else {\n   newMsg.bounds.min = min;\n}\nif (msg.payload.temperature &gt; max) {\n   newMsg.bounds.max = msg.payload.temperature;\n   context.set('max', msg.payload.temperature);\n} else {\n   newMsg.bounds.max = max;\n}\n\nreturn newMsg;","outputs":1,"noerr":0,"x":875.5,"y":336,"wires":[["dbe1013a.863be8","f5bb5785.45e55","b809b11b.7f47c8"]]},{"id":"b809b11b.7f47c8","type":"ui_template","z":"35963a2e.6aa056","group":"c86b0ed1.65efc8","name":"Max and Min","order":2,"width":"6","height":"2","format":"</your></p><div layout="\&quot;row\&quot;" layout-align="\&quot;start" center\"="">\n  <span flex="">Temp Min: </span>\n  <span flex="">Temp Max: </span>\n</div>
<p>\n</p><div layout="\&quot;row\&quot;" layout-align="\&quot;start" center\"="" ng-repeat="\&quot;bounds" in="" msg\"="">\n  <span flex="" style="\&quot;color:" green\"="">{{bounds.min}}</span>\n  <span flex="" style="\&quot;color:" red\"="">{{bounds.max}}</span>\n</div>

Voice Activated Wio Node temperature sensor

Here at Cranfield University we are interested in the ‘Internet of Things’ for environmental sensing. In this blog, we use one off SeedStudio’s Wio Node devices, with a home-made connection to a one wire temperature sensor, and finally an IOS shortcut on an iPhone to read and speak the value using Siri. In part, this blog follows this project.


The WioNode from SeeedStudio

Microprocessor: We’ve had a few projects reported here with Arduino’s, Photons and Raspberry Pis, so it was interesting to get hold of a Wio Node device from Seeed Studio. This is an inexpensive ESP8266 based open-source Wi-Fi development board that supports Seeed’s Plug-n-Play Grove standard. There are two Grove sockets on the Node device. The node is marketed as permitting one to create a working IoT application in 5 minutes. Key to this is the Plug-n-Play physical sensor design, and the modular software tools in the app.

Sensor: To measure temperature, we used a DS18B20 Waterproof Temperature Sensor, available cheaply from a range of sources, such as here. The three wires are Red(VCC), Yellow (DATA), Black(GND).


The Grove standard is a modular, standardized connector prototyping system, permitting Plug-n-Play connectivity with scores of sensor devices for measuring a wide range of phenomena. The advantage of Seeed Studio’s Wio range is that these simply plug into the sockets on the board. However, if one has a sensor without a Grove plug, there is a Protoshield prototyping board available. This can be used to wire up a sensor such as the DS18B20 to allow it to be connected.

Unfortunately we didn’t have a Protoshield, however, we did have a pre-wired grove compatible plug that fitted the socket on the Wio Node – so a visit to the trusty soldering iron and heat-shrink cable was required. To make the DS18B20 work, a 4.7k pull-up resistor is required between the VCC and signal lines. The wiring diagram is as follows:

Wio Node wiring diagram

After wiring up the temperature sensor as shown, and plugging it in, we could turn to the software to control it.

Software controller

Wio Link Configuration

There is a Wio Link App available for smartphones, such as the Apple phone, that hugely simplifies the process of plugging in and operating sensors. We installed the app, and followed the simple instructions to add a new Wio Node device, and to enable Wi-Fi on it. Once this was working, we configured the Node to add our new sensor to the ‘S0’ port (there are two ports – S0 and S1).

REST endpoints for new sensor

The option used was ‘One Wire Temperature Sensor’ on the GPIO toolbar. Once this was working, we ‘flashed’ the new settings onto the Node via the ‘Update Firmware’ option. Next, we could view the API settings for the new configuration.

The URL REST endpoints are shown and can be used to access the temperature value from the sensor. A test option within the app allows one to access the reading directly.

The REST URL takes the form, thus:


The temperature values are returned as a JSON string, appearing thus:


To access the actual value from the JSON, we will need to extract the number from the data pair (see step 3 below). Once we were happy the approach was all working, we copied the URL off for use in the next stage of the project.

Voice control

The project at this point is all working well – the temperature sensor reports to the Wio Node, and an API REST URL can be used to access the value. However, we can go further. We next used an Apple iPhone X, and its newly introduced ‘Shortcuts’ capability. This involves firstly installing the Shortcuts app from the iTunes App Store.

Shortcuts allow one to build a relatively sophisticated programme very simply. We therefore set out to develop a ‘Shortcut’ that accessed the new sensor – for this we needed the URL (REST endpoint) from before. The shortcut settings are shown below, namely: (1) URL – enter in the URL from above; (2) Get Contents of URL [use Advanced options – method: GET, Header: temperature; (3) Get Dictionary Value [Key – temperature]; (4) Set Variable [Temperature] (saves value off to a new variable called Temperature); (5) Text [degrees Celsius] (creates a block of text to append); (6) Add to Variable [Temperature] (appends text to variable); (7) Combine Text [Separator – New Lines]; (8) Speak Text [Wait Until Finished]. A further elaboration is to use the ‘If‘ statement to check there was a valid reading (e.g. temperature > -20) ‘Else‘ advise of a problem.

We then added a custom icon ‘glyph’ (thermometer!) and colouring for the shortcut, and added this to the home screen of the phone. This allows the shortcut to be run easily.

As a final finishing touch, we then also added a Siri shortcut with a simple voice command ‘temperature’ – this allows one to call ‘Hey Siri’ and give the command. The device sensor temperature reading is then spoken back. Pretty amazing! See the video below for an example.


This approach worked well, and could be developed to work with any of the other Grove sensors plugged into the Wio Node. For more complex projects, the Wio Node, with its two connectors could be limiting. Fortunately there are a whole range of extended micro controllers, such as the Wio Link, with 6 Grove connectors – as well as lots of great projects to try.