Radio LCD Thermostat
This document will guide you through the Radio LCD Thermostat project. With this gadget you will be able to control remotly you temperature.
Block Concept
Requirements
-
Either Display Set, or individual components:
- 1x LCD Module
- 1x Core Module
- 1x Mini Battery Module
- 1x Radio Dongle
-
One of these options:
- HARDWARIO Playground installed (recommended) You can find more information in the Quick Start Guide document.
- Raspberry Pi with the HARDWARIO Raspbian distribution You can find more information in the document Raspberry Pi Installation.
- HARDWARIO Firmware Tool installed You can find more information in the document Toolchain Setup.
Firmware Upload
In this procedure we will use the HARDWARIO Playground to upload firmware to the Core Module.
Step 1: Connect the Micro USB cable to the Core Module and your computer
Step 2: Flash firmware
Run the HARDWARIO Playground. In the Firmware tab choose and upload the bcf-radio-lcd-thermostat firmware to the Core Module:
Flashing Core Module R1 & R2 For differences of flashing older Core Module 1 and newer Core Module 2 please read Core Module R1 and R2 comparison in the Hardware section
Step 3: Remove the Micro USB cable from the Core Module and your computer
At this point your firmware is successfully uploaded.
Hardware Assembling
See short video with easy step by step demonstration:
Step 1: Start with the Mini Battery Module
Make sure the Mini Battery Module does not have batteries inserted.
Step 2: Plug the Core Module on top of the Mini Battery Module
Step 3: Plug the LCD Module on top of the Core Module
Playground Bootstrap
If you are using the new HARDWARIO Playground, then use the Functions tab instead of using http://localhost:1880/. Also the pairing process is now done in Devices tab. For communication test use the Messages tab.
Step 1: Open Node-RED in your web browser
Step 2: You should see the empty workspace with Flow 1
Step 3: Insert the following snippet in the flow (using Menu >> Import)
[{"id":"2fc604fc.3b6abc","type":"inject","z":"dfc861b.b2a02a","name":"List all gateways","topic":"gateway/all/info/get","payload":"","payloadType":"str","repeat":"","crontab":"","once":false,"x":560,"y":460,"wires":[["a2c10833.24d5d8"]]},{"id":"1e4502b8.2f63fd","type":"inject","z":"dfc861b.b2a02a","name":"Start node pairing","topic":"gateway/usb-dongle/pairing-mode/start","payload":"","payloadType":"str","repeat":"","crontab":"","once":false,"x":570,"y":580,"wires":[["795ff5a7.8e266c"]]},{"id":"3d844ce2.932864","type":"inject","z":"dfc861b.b2a02a","name":"Stop node pairing","topic":"gateway/usb-dongle/pairing-mode/stop","payload":"","payloadType":"str","repeat":"","crontab":"","once":false,"x":560,"y":640,"wires":[["5967c452.c838bc"]]},{"id":"f202b253.2705b","type":"inject","z":"dfc861b.b2a02a","name":"List paired nodes","topic":"gateway/usb-dongle/nodes/get","payload":"","payloadType":"str","repeat":"","crontab":"","once":false,"x":560,"y":520,"wires":[["f0aca138.0b2c3"]]},{"id":"349f02fd.890f6e","type":"inject","z":"dfc861b.b2a02a","name":"Unpair all nodes","topic":"gateway/usb-dongle/nodes/purge","payload":"","payloadType":"str","repeat":"","crontab":"","once":false,"x":560,"y":700,"wires":[["2f1c5bb6.53d6f4"]]},{"id":"cf61d75d.4ad8f8","type":"mqtt in","z":"dfc861b.b2a02a","name":"","topic":"#","qos":"2","broker":"67b8de4a.029d3","x":530,"y":400,"wires":[["a5cb0658.f5d658"]]},{"id":"a5cb0658.f5d658","type":"debug","z":"dfc861b.b2a02a","name":"","active":true,"console":"false","complete":"false","x":790,"y":400,"wires":[]},{"id":"a2c10833.24d5d8","type":"mqtt out","z":"dfc861b.b2a02a","name":"","topic":"","qos":"","retain":"","broker":"717f7c18.ba0a24","x":770,"y":460,"wires":[]},{"id":"f0aca138.0b2c3","type":"mqtt out","z":"dfc861b.b2a02a","name":"","topic":"","qos":"","retain":"","broker":"717f7c18.ba0a24","x":770,"y":520,"wires":[]},{"id":"795ff5a7.8e266c","type":"mqtt out","z":"dfc861b.b2a02a","name":"","topic":"","qos":"","retain":"","broker":"717f7c18.ba0a24","x":770,"y":580,"wires":[]},{"id":"5967c452.c838bc","type":"mqtt out","z":"dfc861b.b2a02a","name":"","topic":"","qos":"","retain":"","broker":"717f7c18.ba0a24","x":770,"y":640,"wires":[]},{"id":"2f1c5bb6.53d6f4","type":"mqtt out","z":"dfc861b.b2a02a","name":"","topic":"","qos":"","retain":"","broker":"717f7c18.ba0a24","x":770,"y":700,"wires":[]},{"id":"67b8de4a.029d3","type":"mqtt-broker","z":"","broker":"127.0.0.1","port":"1883","clientid":"","usetls":false,"compatmode":true,"keepalive":"60","cleansession":true,"willTopic":"","willQos":"0","willPayload":"","birthTopic":"","birthQos":"0","birthPayload":""},{"id":"717f7c18.ba0a24","type":"mqtt-broker","z":"","broker":"127.0.0.1","port":"1883","clientid":"","usetls":false,"compatmode":true,"keepalive":"60","cleansession":true,"willTopic":"","willQos":"0","willPayload":"","birthTopic":"","birthQos":"0","birthPayload":""}]
It will look like this:
This snippet provides control buttons for gateway/radio commands. These commands are sent over the MQTT protocol.
Step 4: Deploy the flow using the Deploy button in the top-right corner
Step 5: Open the debug tab
In the debug tab, you will be able to see all the MQTT messages.
Step 6: Click on the List all gateways button. You should see a response like this in the debug tab
At this point, you've got working Node-RED, MQTT, HARDWARIO Radio Dongle and HARDWARIO Gateway.
Radio Pairing
In this section, we will create a radio link between the Radio Dongle and the Radio LCD Thermostat.
Follow these steps in Node-RED:
Step 1: Click on the Start node pairing button
Step 2: Insert the batteries into the Radio LCD Thermostat to send the pairing request (you should also see the red LED on the Core Module to be on for about 2 seconds)
Step 3: Click on the Stop node pairing button
At this point, you've got established a radio link between the node (Radio LCD Thermostat) and the gateway (Radio Dongle).
Communication Test
Follow these steps in Node-RED:
Step 1: Switch to debug tab on the right
Step 2: Insert the following snippet in the flow (using Menu >> Import)
[{"id":"12b3deae.bbbdf1","type":"mqtt in","z":"f2f80e07.95983","name":"","topic":"node/lcd-thermostat:0/#","qos":"2","broker":"25b87ea5.743312","x":390,"y":320,"wires":[["7694514b.9b64d"]]},{"id":"7694514b.9b64d","type":"debug","z":"f2f80e07.95983","name":"","active":true,"console":"false","complete":"false","x":630,"y":320,"wires":[]},{"id":"25b87ea5.743312","type":"mqtt-broker","z":"","broker":"127.0.0.1","port":"1883","clientid":"","usetls":false,"compatmode":true,"keepalive":"60","cleansession":true,"willTopic":"","willQos":"0","willPayload":"","birthTopic":"","birthQos":"0","birthPayload":""}]
Step 3: If you see some messages in debug log (like temperature) your kit works correctly
At this point, you've got verified radio communication.
Integration with Blynk IoT
Now that the kit is assembled and sending data over MQTT, let's display the temperature on your phone with Blynk IoT (the current Blynk platform — the old Blynk Legacy cloud has been discontinued). In this example you'll graph the measured temperature together with your set-point, while the relay keeps switching locally based on that set-point.
See the canonical HARDWARIO guide, Blynk app integration, for how to create a Blynk account, a device template, datastreams, and a device. It also explains where to find the Auth Token and Template ID you'll need below.
Step 1: Create a template and datastreams
In the Blynk IoT web console, create a device template, then add one Datastream (a Virtual Pin) for each value you want to display:
| Value | Virtual Pin | Type | Unit |
|---|---|---|---|
| Measured temperature | V1 | Double | °C |
| Set-point temperature | V2 | Double | °C |
Set a sensible range for each datastream (for example 0 – 50). Then create a device from this template — see the guide for the exact steps.
Step 2: Configure the Node-RED flow
On the Node-RED canvas, subscribe to the two MQTT topics published by the thermostat and forward them to Blynk:
node/lcd-thermostat:0/thermometer/0:1/temperature→ the measured temperaturenode/lcd-thermostat:0/thermometer/set-point/temperature→ the set-point
The relay logic stays entirely local: a switch node compares the measured
temperature against the set-point and publishes true/false to
node/power-controller:0/relay/-/state/set, exactly as before. This part does not
involve Blynk.
To send each value to the phone, add a Blynk IoT Write node (you'll find it on the left under the Blynk IoT section) after each temperature topic:
- the measured-temperature node → Virtual Pin
1 - the set-point node → Virtual Pin
2
Step 3: Point the Write nodes at Blynk IoT
Double-click a Write node and click the small pencil to open the client
configuration. In the Url field enter blynk.cloud, and copy the Auth Token
and Template ID from your device detail in the Blynk web console. Confirm with
Add. Back in the node, set the Virtual Pin number (without the letter "V"),
then click Done. Reuse the same client for both Write nodes.
When both nodes are wired, click Deploy in the top-right corner.
Step 4: Add a widget in the Blynk IoT app
Download the Blynk IoT app from the App Store or Google Play and sign in with the same account. Open your device, then add a Chart widget (to watch the temperature over time) or a Gauge. Open the widget's settings and bind it to the Datastream for the virtual pin you chose. Once Node-RED is deployed, the values start streaming in and you're done!