Skip to main content

Experiment

Time allocation: 10 min.

Controlling an LED Strip with an IoT Button​

Experiment Description​

In this experiment, we will control an LED strip using a button based on the measured temperature. We will also learn how to work with the RGB color model.

Experiment Steps​

  1. Assembling the button
  2. Assembling the LED strip controller
  3. Connecting the button to the Playground
  4. Setting up the LED strip control function

Assembling the Button​

Modules in the setup:

  • Core Module
  • Mini Battery Module
  • Push Button Module

Assemble the unit following the video tutorial:

Assembling the LED Strip Controller​

Modules in the setup:

  • Core Module
  • Power Module
  • LED Pásek

Assemble the unit following the video tutorial:

Connecting the Units to the Playground​

(If you don’t have the application installed yet, please download it and install it)

  1. Plug the Radio Dongle into your computer’s USB port
  2. Open the Playground application and go to the Devices tab
  3. Select your Radio Dongle from the list of USB devices and click Connect
  4. Click on Start pairing
  5. Insert the battery into the button — a new device labeled push-button:0 should appear
  6. Click Start pairing again
  7. Plug the adapter for the LED strip controller into the socket — a new device labeled power-controller:0 should appear
info

If a new device appears with a different label, you’ll need to upload the correct firmware. Check out this guide on uploading firmware. You’ll need twr-radio-push-button for the button and twr-radio-power-controller for the LED strip controller.

Setting up the Function to Display Button Press Count and Temperature​

  1. Go to the Functions tab 2.Import this flow:
[{"id":"e1c78aec22a2b30f","type":"tab","label":"IoT button","disabled":false,"info":""},{"id":"df77fa76ec57b83c","type":"mqtt in","z":"e1c78aec22a2b30f","name":"","topic":"node/push-button:0/push-button/-/event-count","qos":"2","datatype":"auto","broker":"a382db22.fb11e8","inputs":0,"x":200,"y":180,"wires":[["f459f618531641e5"]]},{"id":"db42bc1c50d5c6bf","type":"mqtt in","z":"e1c78aec22a2b30f","name":"","topic":"node/push-button:0/thermometer/0:1/temperature","qos":"2","datatype":"auto","broker":"29fba84a.b2af58","inputs":0,"x":210,"y":360,"wires":[["f285b637e508b347"]]},{"id":"f285b637e508b347","type":"ui_text","z":"e1c78aec22a2b30f","group":"57ff470b.93fdf8","order":3,"width":0,"height":0,"name":"","label":"Temperature","format":"{{msg.payload}}°C","layout":"row-spread","className":"","x":550,"y":360,"wires":[]},{"id":"f459f618531641e5","type":"ui_text","z":"e1c78aec22a2b30f","group":"57ff470b.93fdf8","order":4,"width":0,"height":0,"name":"","label":"Counter","format":"{{msg.payload}}","layout":"row-spread","className":"","x":540,"y":180,"wires":[]},{"id":"a382db22.fb11e8","type":"mqtt-broker","name":"","broker":"127.0.0.1","port":"1883","clientid":"","autoConnect":true,"usetls":false,"protocolVersion":"4","keepalive":"60","cleansession":true,"birthTopic":"","birthQos":"0","birthPayload":"","birthMsg":{},"closeTopic":"","closeQos":"0","closePayload":"","closeMsg":{},"willTopic":"","willQos":"0","willPayload":"","willMsg":{},"sessionExpiry":""},{"id":"29fba84a.b2af58","type":"mqtt-broker","name":"","broker":"127.0.0.1","port":"1883","clientid":"","autoConnect":true,"usetls":false,"protocolVersion":"4","keepalive":"60","cleansession":true,"birthTopic":"","birthQos":"0","birthPayload":"","birthMsg":{},"closeTopic":"","closePayload":"","closeMsg":{},"willTopic":"","willQos":"0","willPayload":"","willMsg":{},"sessionExpiry":""},{"id":"57ff470b.93fdf8","type":"ui_group","name":"Default","tab":"11207769.c31889","order":1,"disp":true,"width":"6","collapse":false},{"id":"11207769.c31889","type":"ui_tab","name":"Home","icon":"dashboard"}]
  1. Click the Deploy button in the top right corner
  2. Go to the Messages tab — if everything is working, you should see incoming messages from the push-button
  3. Go to the Dashboard tab — if everything is working, you should see the button press count and its temperature
info

Note:

  1. Blow on the button to speed up data transmission
  2. The unit sends temperature data every 15 minutes; button presses are sent immediately
  3. If the temperature rises by more than 0.2 °C between two measurements, the unit sends data immediately

Setting up the LED Strip Control Function​

  1. Go to the Functions tab
  2. Import this flow:
[{"id":"b0e6a61052f6464e","type":"tab","label":"LED controler","disabled":false,"info":""},{"id":"c150a9bf93daec3d","type":"mqtt out","z":"b0e6a61052f6464e","name":"","topic":"node/power-controller:0/led-strip/-/color/set","qos":"","retain":"","respTopic":"","contentType":"","userProps":"","correl":"","expiry":"","broker":"54516ae2.8f3d14","x":910,"y":120,"wires":[]},{"id":"c1d16ecd5e7996a6","type":"mqtt in","z":"b0e6a61052f6464e","name":"","topic":"node/push-button:0/push-button/-/event-count","qos":"2","datatype":"auto","broker":"54516ae2.8f3d14","nl":false,"rap":false,"inputs":0,"x":200,"y":120,"wires":[["dc7bbeb8ef8e5bea"]]},{"id":"0e2d5607022ff3d2","type":"mqtt in","z":"b0e6a61052f6464e","name":"","topic":"node/push-button:0/thermometer/0:1/temperature","qos":"2","datatype":"auto","broker":"54516ae2.8f3d14","nl":false,"rap":false,"inputs":0,"x":210,"y":200,"wires":[["421ceca3a1e659e6"]]},{"id":"e3fdded3dab459dd","type":"change","z":"b0e6a61052f6464e","name":"Color change","rules":[{"t":"set","p":"payload","pt":"msg","to":"\"#FF0000\"","tot":"str"}],"action":"","property":"","from":"","to":"","reg":false,"x":640,"y":200,"wires":[["c150a9bf93daec3d"]]},{"id":"421ceca3a1e659e6","type":"switch","z":"b0e6a61052f6464e","name":"Condition","property":"payload","propertyType":"msg","rules":[{"t":"gt","v":"25","vt":"num"}],"checkall":"true","repair":false,"outputs":1,"x":480,"y":200,"wires":[["e3fdded3dab459dd"]]},{"id":"dc7bbeb8ef8e5bea","type":"change","z":"b0e6a61052f6464e","name":"Color change","rules":[{"t":"set","p":"payload","pt":"msg","to":"\"#0000FF\"","tot":"str"}],"action":"","property":"","from":"","to":"","reg":false,"x":640,"y":120,"wires":[["c150a9bf93daec3d"]]},{"id":"54516ae2.8f3d14","type":"mqtt-broker","name":"","broker":"localhost","port":"1883","clientid":"","autoConnect":true,"usetls":false,"protocolVersion":"4","keepalive":"60","cleansession":true,"birthTopic":"","birthQos":"0","birthPayload":"","birthMsg":{},"closeTopic":"","closePayload":"","closeMsg":{},"willTopic":"","willQos":"0","willPayload":"","willMsg":{},"sessionExpiry":""}]
  1. Click the Deploy button in the top right corner
  2. Go to the Messages tab — if everything is working, you should see incoming messages from the power-controller
  3. The flow is now configured so that: • When the temperature exceeds 25 °C, the LED strip changes color to red • When the button is pressed, the LED strip changes color to blue
  4. If everything is working properly, you should be able to control the LED strip color based on the set conditions