Upload sensor values to Blynk and display them using Gauges on the Blynk platform.
In this example, there are 2 parts involved.
Create a device on Blynk and obtain its token.
1. Go to https://blynk.io/
1. Go to Developer Zone > My Templates, and click “+ New Template”.
1. Go to Datastreams, click “+ New Datastream” and select “Virtual Pin”.
1. Go to Web Dashboard.
Since the device will always be offline, a notification will be triggered with every interaction. By disabling this notification, we can prevent alerts about the offline status when interacting with the device.
1. Go to Devices. Click “+ New Device”.
1. Open the Blynk App and log in to your account.
Program the micro:bit to send sensor values to Blynk.
1. Initialize IoT:bit to connect to a designated WiFi network and display the connection status when successful. You may refer to the first chapter for instructions on how to connect to WiFi.
For demonstration, a random number is sent to Blynk every 1 second.
1. Get the “On Blynk Uploaded” handler from IoT:bit > IoT Services.
MakeCode: [https://makecode.microbit.org/_2v1FqMJebYJU](https://makecode.microbit.org/_2v1FqMJebYJU)
### Result
If the upload is successful, it will show OK as the status with error code 0.
Create a switch on Blynk to control the output of the micro:bit.
In this example, there are 2 parts involved.
Create a switch on Blynk and configure it to send data to the micro:bit.
We will continue to use the template created in section 9.1.1. Go to Developer Zone > My Templates. Choose the template we just created.
1. Go to Datastreams and click “Edit”.
1. Go to Web Dashboard, drag a Switch to the Dashboard area.
1. Open the Blynk App.
Program the micro:bit to respond to input from Blynk.
1. Initialize IoT:bit to connect to a designated WiFi network. You may refer to the first chapter for instructions on how to connect to WiFi.
1. In “forever”, use if-statement to check WiFi connection status.
1. Get the “On Blynk Readed” handler from IoT:bit > IoT Services.
MakeCode: [https://makecode.microbit.org/_CfDHut4T7Eif](https://makecode.microbit.org/_CfDHut4T7Eif)
### Result
We can change the value of the read pin using the switch on Blynk to check if the micro:bit can correctly receive the data.
Description:
In Part 1, we will create a device on Blynk and obtain its token.
In Part 2, we will program the micro:bit to send sensor values to Blynk.
### Part 1: Blynk Configuration
Goal:
Step 1: Create an Account
2. Register an account and log in to the platform according to the website's instructions.
Step 2: Create a Template
2. Input name, hardware and connection type accordingly. Click “Done” when finished.
- Name: iotbit
- Hardware: Other
- Connection type: WiFi
Step 3: Configure the Datastream - Add V0
2. Change the configuration of the Pin accordingly. Click “Create” when finished.
- Name: Sensor Value
- Max: 100
Step 4: Configure the Web Dashboard
2. Drag a Gauge to the Dashboard area.
3. Hover over the Gauge, click the button shown below to change its settings
4. Choose Sensor Value (V0) as the Datastream. Click “Save” when finished.
Step 5: Disable Notification Upon Interaction
1. Go to Connection Lifecycle.
2. Scroll down to Offline and click Settings.
3. Disable “Display notification upon user interaction”.
4. Click “Save” to save the entire template.
Step 6: Create a Device With the Template
2. Click “From template” and select the template we just created.
3. Rename the device as “iotbit 1” at Device Name. Click “Create” when finished.
4. Go to the Devices page and copy the token as shown below. Keep the copied token in a safe place for future use.
Step 7 (Optional): Configure the Mobile Dashboard
2. After logging in, you will find the device you just created on the page.
3. Switch to Developer Mode by clicking the button at the top right-hand side.
4. Click on the template you just created.
5. Click “+” and choose “Gauge”. A Gauge will be shown on the dashboard automatically.
6. Click the newly created Gauge and choose Sensor Value (v0) as its datastream.
### Part 2: Programming (MakeCode)
Goal:
Step 1: Connect to WiFi
2. Snap “initialize OLED with width 128 height 64” to “on start”.
Step 2: Send Data to Blynk
1. In “forever”, use if-statement to check WiFi connection status.
2. Snap the “Send Blynk token.....” block inside the if-statement.
3. Copy the token from Blynk and fill it into “Send Blynk token”.
4. Snap “pick random 0 to 10” to V0 value inside “Send Blynk token”. Change the range to “0 to 100”.
5. Snap a pause to the loop. Set the pause to be 1000 ms (1 second).
Step 3: Show Blynk Upload Status
2. Use OLED to display the upload status and error code.
Full Solution
On Blynk, you will see the value of the Gauge keep changing randomly, which is controlled by the data sent from your Micro:bit.
**Web Dashboard:**
**Mobile Dashboard:**
If the upload fails, it will show FAIL as the status with the respective error code which represents the reason of failure.
- Error code 400: The user inputted the wrong token.
- Error code -28674: There is no internet connection.
## Session 2: Get Controlled by Blynk
Goal:
Description:
In Part 1, we will create a switch on Blynk and configure it to send data to the micro:bit.
In Part 2, we will program the micro:bit to respond to input from Blynk.
### Part 1: Blynk Configuration
Goal:
Step 1: Use Existing Template
Otherwise, create a new template following the first half chapter of step 1 and 2.
Step 2: Update the Datastream - Add V1
2. Click “+ New Datastream” and select “Virtual Pin”.
3. Change the name of the pin to “on_off switch”. Click “Create” when finished.
Step 3: Add a Switch to the Web Dashboard
2. Hover over the Switch and go into its settings.
3. Choose on_off switch (V1) as the Datastream. Click “Save” when finished.
4. Click “Save And Apply” to save the entire template.
Step 4 (Optional): Configure the Mobile Dashboard
2. Switch to Developer Mode by clicking the button at the top right-hand side.
3. Click on the template you just updated.
4. Click “+” and choose “Switch”. A Switch will be shown on the dashboard automatically.
5. Click the newly created Switch and choose on_off switch (v1) as its datastream.
### Part 2: Programming (MakeCode)
Goal:
Step 1: Connect to WiFi
2. Snap “initialize OLED with width 128 height 64” to “on start”.
Step 2: Read Data from Blynk
2. Snap the “read Blynk token.....” block inside the if-statement.
3. Copy the token from Blynk and fill it into “read Blynk token”.
4. Choose V1 for “read Blynk token.....”.
5. Snap a pause to the loop. Set the pause to be 1000 ms (1 second).
Step 3: Display the Data Read
2. Create a variable to store the value read from Blynk.
3. Use OLED to display the read pin and its value.
4. Show the respective icon according to the read data.
Full Solution
You could also download the program from the following website:
1. When the Switch in on
**Web Dashboard:**
**Mobile Dashboard:**
2. When the Switch is off
**Web Dashboard:**
**Mobile Dashboard:**
