Button for parents

Introduction

You know the feeling: you're deep in a game or listening to loud music, and when your mum calls you for dinner, you have no idea. So build your parents a smart button that lets them call you through your phone, without shouting all over the house.

In this project, you will learn how to send a message to a phone with a button, from anywhere in the house. 👌

You will need the box with a button and the USB dongle, so the basic HARDWARIO Start Set is all you need.

Get it started in Node-RED

1. Assemble the Start Set and pair it. The Core Module needs the twr-radio-push-button firmware.
2. In Playground, click the Functions tab. This is where you set up the box to do whatever you want.
3. Let's start programming. 🤞 Place a light purple bubble, called a node, on the Node-RED workspace. You'll find it on the left as mqtt in in the network section.

If you're opening the program for the first time: this node is already on the workspace, preset as node/#. You can delete the second, dark green bubble.

4. In the node, you set up the key function: the button press. Double-click the node and copy this line into the Topic field:

node/push-button:0/push-button/-/event-count

Confirm with Done.

Tip: Do you see the Messages tab in Playground? It shows every event, line by line. Press the button on the box and… ta-da, the same line appears:

node/push-button:0/push-button/-/event-count

What does that mean? Next time, you can copy lines into the Topic field straight from the Messages tab.

Write your own message

1. You set the message here in Node-RED too. Anywhere next to the light purple MQTT input, place the yellow change node from the function section.

2. The change node decides what happens when the button is pressed, for example that a message is sent. Let your imagination run wild and write your own (just remember that Blynk doesn't show accented letters such as č or á). A little inspiration:
   • Grub's up!
   • Feeding time
   • Fill your belly with real mana
   • Your health potion is ready

Just double-click the node and write the message on the second line of the Rules field.

Confirm with Done.

3. On the edge of each node there's a small grey dot. Click it, hold the mouse button and drag to the side, and you'll pull a wire out of the node. That's how nodes are connected. Try it out. Connect the two nodes by dragging the mouse from one bubble to the other. Easy. 🙆

Prepare the Blynk IoT app

The box with the button connects to a smartphone through the Blynk IoT app. Node-RED sends the text of the message to Blynk, and a Blynk automation turns every new message into a push notification.

1. If you don't have a Blynk IoT account yet, create one. The free plan is enough for this project: at the time of writing, it includes push notifications in the app and up to five automations.

2. The next step is to create a device template. Blynk's quick guide shows you how. If you have a template from an earlier project, feel free to use it.

3. Now set up a new datastream. In the template details, open the Datastreams tab, click New Datastream and choose Virtual Pin. The datastream settings open.

4. Name the new datastream (for example Message) and pick one of the free pins, for example V2. The notification on your phone should show your own message, so choose String as the Data Type (a text string).

5. In the datastream settings, also allow automations to use it as a condition: in the Automations section, turn on Use as Condition. Create the datastream by clicking Create.

6. Save the template with the Save button in the top right corner.

Create a device

If you don't have one yet, create a device from the template: in Devices, add a new device, choose your template and give the device a name. You'll find its Auth Token on the device's Device Info tab. You'll need it in Node-RED.

Create an automation

1. Switch to the Automations section and create a new automation.

2. Choose Device State as the condition. The automation then runs every time Node-RED sends Blynk a new message.

3. Setting up the automation is simple: under When, you decide when it runs, and under Do this, what happens next.

4. Start with When. Choose your device and the datastream you created. A third dropdown appears: leave it set to Is Any. The automation then reacts to every message, even when it's the same as the last one.

5. Under Do this, add the action that sends a notification to the mobile app (Send In-App Notifications) and choose yourself as the recipient. Put the Trigger value placeholder ({TRIGGER_VALUE}) in the notification text. Blynk replaces it with the text of your message.

6. Finally, don't forget to name the automation. Limit period sets how soon the automation may run again. Choose the shortest option, otherwise a second message sent soon after the first won't arrive.

7. Save the automation by clicking Save.

Set up the app on your phone

😎 Download the Blynk IoT app to your phone from the App Store or Google Play. Sign in with the same account and allow notifications, so the message can pop up.

Connect your phone to the box

1. Go back to your computer. On the Node-RED workspace, add the green write node after the two nodes. You'll find it on the left in the Blynk IoT section (the Blynk ws section belongs to the old Blynk, which no longer works).
2. Double-click the node to open it. Next to Connection you'll see a small pencil. Click it and a new window opens.
3. In the Url field, enter blynk.cloud.
4. Into the Auth Token and Template ID fields, copy the values from the Blynk web app on your computer: the Auth Token is on the device's Device Info tab, the Template ID in the template details.
5. Confirm the settings with Add.
6. In the Virtual Pin field, enter the number of the datastream's pin (2 for V2) and save everything with Done.
7. Connect the write node to the node where you set your message. You've now programmed the device so that pressing the button on the box ➡️ turns into a message ➡️ that travels all the way to your phone. 👾

❗ Start the whole flow with the red Deploy button in the top right corner. 🚨

Action!

1. Press the button and… magic! 🎇 The message appears on your phone! 🙌
2. Give the button to your mum or dad. Amazed, aren't they? Family peace before dinner is saved. 🤓