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In this blog, we'll explore how to create a web-based temperature monitor using the Thingy:52 sensor and the Web Bluetooth API. This project will guide you through setting up the hardware, connecting it to your web application via Bluetooth, and displaying the real-time temperature data on a web chart. Let's get started!
Components Required- Thingy:52
- Computer or mobile device with Bluetooth support
- A web server to host your web application (optional)
Thingy:52 is a compact, versatile sensor platform designed for IoT applications.
It features various sensors, including temperature, humidity, air quality, and more. Before diving into the code, ensure your Thingy:52 is powered on and ready for Bluetooth connections.
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Creating the Web Application1. Setting Up the HTML StructureCreate an HTML file to serve as the structure of your web application. This file will include the necessary elements for connecting to Thingy:52 and displaying the temperature data.
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Thingy:52 Temperature Monitor</title>
<script src="https://cdn.jsdelivr.net/npm/chart.js"></script>
</head>
<body>
<h1>Thingy:52 Temperature Monitor</h1>
<button id="connectButton">Connect</button>
<canvas id="temperatureChart" width="400" height="200"></canvas>
<p id="temperatureData">Temperature: --°C</p>
<script src="main.js"></script>
</body>
</html>Next, create a JavaScript file (main.js) to handle the Bluetooth connection, read the temperature data, and update the chart.
Initialize Chart.js
First, let's initialize a line chart using Chart.js to display the temperature data.
const ctx = document.getElementById('temperatureChart').getContext('2d');
const temperatureChart = new Chart(ctx, {
type: 'line',
data: {
labels: [],
datasets: [{
label: 'Temperature (°C)',
data: [],
borderColor: 'rgba(75, 192, 192, 1)',
borderWidth: 1
}]
},
options: {
scales: {
x: {
type: 'time',
time: {
unit: 'second'
}
},
y: {
beginAtZero: true
}
}
}
});Connect to Thingy:52 via Web Bluetooth
Add the following code to handle the Bluetooth connection and read the temperature data from Thingy:52.
const connectButton = document.getElementById('connectButton');
const temperatureData = document.getElementById('temperatureData');
let thingyDevice;
let temperatureCharacteristic;
connectButton.addEventListener('click', async () => {
try {
thingyDevice = await navigator.bluetooth.requestDevice({
filters: [{ services: ['ef680200-9b35-4933-9b10-52ffa9740042'] }]
});
const server = await thingyDevice.gatt.connect();
const service = await server.getPrimaryService('ef680200-9b35-4933-9b10-52ffa9740042');
temperatureCharacteristic = await service.getCharacteristic('ef680201-9b35-4933-9b10-52ffa9740042');
temperatureCharacteristic.addEventListener('characteristicvaluechanged', handleTemperatureData);
await temperatureCharacteristic.startNotifications();
console.log('Connected to Thingy:52');
} catch (error) {
console.error('Error connecting to Thingy:52', error);
}
});
function handleTemperatureData(event) {
const value = event.target.value.getUint8(0);
const temperature = value / 10;
temperatureData.textContent = `Temperature: ${temperature}°C`;
const currentTime = new Date();
temperatureChart.data.labels.push(currentTime);
temperatureChart.data.datasets[0].data.push(temperature);
temperatureChart.update();
}This code handles the following tasks:
- Connects to the Thingy:52 device via Bluetooth.
- Subscribes to the temperature characteristic to receive updates.
- Reads and processes the temperature data.
- Updates the Chart.js chart with the new temperature data.
To run the web application, you can simply open the index.html file in a web browser that supports the Web Bluetooth API (e.g., Chrome, Edge).
If you're hosting the application on a web server, ensure the server supports HTTPS, as Web Bluetooth requires a secure context.
Here is the complete HTML file.
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Thingy:52 Temperature Monitor</title>
<script src="https://cdn.jsdelivr.net/npm/chart.js"></script>
<style>
:root {
--bg-primary: #1a1a1a;
--bg-secondary: #2d2d2d;
--text-primary: #ffffff;
--accent-color: #00ff9d;
--accent-hover: #00cc7d;
--error-color: #ff4444;
--gradient-start: #2d2d2d;
--gradient-end: #1a1a1a;
}
* {
margin: 0;
padding: 0;
box-sizing: border-box;
transition: all 0.3s ease;
}
body {
font-family: 'Segoe UI', sans-serif;
background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
color: var(--text-primary);
padding: 2rem;
min-height: 100vh;
}
.container {
max-width: 900px;
margin: 2rem auto;
background: rgba(45, 45, 45, 0.8);
padding: 3rem;
border-radius: 1.5rem;
box-shadow: 0 8px 32px rgba(0, 0, 0, 0.4);
backdrop-filter: blur(20px);
}
h1 {
text-align: center;
margin-bottom: 3rem;
font-size: 3rem;
letter-spacing: 2px;
background: linear-gradient(45deg, var(--accent-color), #00ffff, var(--accent-color));
background-size: 200% auto;
-webkit-background-clip: text;
background-clip: text;
color: transparent;
animation: gradient 3s ease infinite;
}
.chart-container {
height: 450px;
margin: 3rem 0;
padding: 1.5rem;
background: rgba(0, 0, 0, 0.3);
border-radius: 1.5rem;
border: 2px solid rgba(255, 255, 255, 0.1);
transition: all 0.4s ease;
}
.chart-container:hover {
transform: translateY(-5px);
}
button {
padding: 0.8rem 1.5rem;
background: linear-gradient(45deg, var(--accent-color), #00ffff);
color: var(--bg-primary);
border: none;
border-radius: 0.5rem;
cursor: pointer;
font-size: 1rem;
font-weight: bold;
display: block;
margin: 0 auto;
transition: all 0.3s ease;
box-shadow: 0 4px 15px rgba(0, 255, 157, 0.2);
}
button:hover {
transform: translateY(-2px);
box-shadow: 0 6px 20px rgba(0, 255, 157, 0.3);
}
button:active {
transform: translateY(0);
}
.status {
font-size: 1.2rem;
padding: 1.2rem;
margin: 2rem 0;
border-radius: 0.5rem;
text-align: center;
background: rgba(0, 0, 0, 0.3);
border: none;
box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
}
.error {
background: rgba(255, 68, 68, 0.2);
border-color: var(--error-color);
animation: shake 0.5s ease-in-out;
}
@keyframes gradient {
0% { background-position: 0% 50%; }
50% { background-position: 100% 50%; }
100% { background-position: 0% 50%; }
}
@keyframes shake {
0%, 100% { transform: translateX(0); }
25% { transform: translateX(-5px); }
75% { transform: translateX(5px); }
}
</style>
</head>
<body>
<div class="container">
<h1>Thingy:52 Temperature Monitor</h1>
<button id="connectButton">Connect to Thingy:52</button>
<div id="statusText" class="status">Ready to connect</div>
<div class="chart-container">
<canvas id="tempChart"></canvas>
</div>
</div>
<script>
const THINGY_SERVICE_UUID = 'ef680200-9b35-4933-9b10-52ffa9740042';
const TEMP_CHARACTERISTIC_UUID = 'ef680201-9b35-4933-9b10-52ffa9740042';
let device = null;
let tempChart = null;
const MAX_DATA_POINTS = 10;
const UPDATE_INTERVAL = 2000; // 5 seconds
let lastUpdateTime = 0;
function initChart() {
const ctx = document.getElementById('tempChart').getContext('2d');
const style = getComputedStyle(document.documentElement);
const accentColor = style.getPropertyValue('--accent-color').trim();
const textColor = style.getPropertyValue('--text-primary').trim();
tempChart = new Chart(ctx, {
type: 'line',
data: {
labels: [],
datasets: [{
label: 'Temperature °C',
data: [],
borderColor: accentColor,
backgroundColor: 'rgba(0, 255, 157, 0.1)',
tension: 0.4,
borderWidth: 3,
pointRadius: 6,
pointBackgroundColor: accentColor,
pointHoverRadius: 8,
pointHoverBorderWidth: 3,
fill: true
}]
},
options: {
responsive: true,
maintainAspectRatio: false,
animations: {
tension: {
duration: 1000,
easing: 'ease-in-out'
}
},
plugins: {
legend: {
labels: {
color: textColor,
font: {
size: 16,
weight: 'bold'
},
padding: 20
}
},
tooltip: {
backgroundColor: 'rgba(0, 0, 0, 0.8)',
titleFont: {
size: 16
},
bodyFont: {
size: 14
},
padding: 12
}
},
scales: {
y: {
beginAtZero: false,
ticks: {
color: textColor,
font: {
size: 14
},
padding: 10
},
grid: {
color: 'rgba(255, 255, 255, 0.1)'
}
},
x: {
ticks: {
color: textColor,
font: {
size: 14
},
padding: 10
},
grid: {
color: 'rgba(255, 255, 255, 0.1)'
}
}
}
}
});
}
function updateChart(temperature) {
const timeString = new Date().toLocaleTimeString();
tempChart.data.labels.push(timeString);
tempChart.data.datasets[0].data.push(temperature);
if (tempChart.data.labels.length > MAX_DATA_POINTS) {
tempChart.data.labels.shift();
tempChart.data.datasets[0].data.shift();
}
tempChart.update('none');
}
function parseTemperature(value) {
const dataView = new DataView(value.buffer);
const integer = dataView.getInt8(0);
const decimal = dataView.getUint8(1);
return integer + decimal/100.0;
}
function updateTemperatureDisplay(temperature) {
const statusEl = document.getElementById('statusText');
const tempStr = temperature.toFixed(1);
statusEl.innerHTML = `
<div style="font-size: 2rem; margin-bottom: 0.5rem">
${tempStr}°C
</div>
<div style="font-size: 0.9rem; opacity: 0.8">
Last updated: ${new Date().toLocaleTimeString()}
`;
}
async function connectToThingy() {
try {
device = await navigator.bluetooth.requestDevice({
filters: [{ namePrefix: 'Thingy' }],
optionalServices: [THINGY_SERVICE_UUID]
});
const server = await device.gatt.connect();
const service = await server.getPrimaryService(THINGY_SERVICE_UUID);
const characteristic = await service.getCharacteristic(TEMP_CHARACTERISTIC_UUID);
await characteristic.startNotifications();
characteristic.addEventListener('characteristicvaluechanged', (event) => {
const now = Date.now();
if (now - lastUpdateTime >= UPDATE_INTERVAL) {
const temperature = parseTemperature(event.target.value);
updateChart(temperature);
updateTemperatureDisplay(temperature);
lastUpdateTime = now;
}
});
document.getElementById('connectButton').textContent = 'Disconnect';
document.getElementById('statusText').textContent = 'Connected';
} catch (error) {
console.error('Error:', error);
document.getElementById('statusText').textContent = error.message;
document.getElementById('statusText').classList.add('error');
}
}
window.addEventListener('load', () => {
initChart();
document.getElementById('connectButton').addEventListener('click', async () => {
if (device?.gatt?.connected) {
await device.gatt.disconnect();
document.getElementById('connectButton').textContent = 'Connect to Thingy:52';
document.getElementById('statusText').textContent = 'Disconnected';
} else {
await connectToThingy();
}
});
});
</script>
</body>
</html>In this blog, we've demonstrated how to create a web-based temperature monitor using the Thingy:52 sensor and the Web Bluetooth API. This project showcases the power of Web Bluetooth for building real-time, interactive IoT applications. You can further enhance this project by adding features such as data logging, and alerts, or integrating other sensors from the Thingy:52 platform. Happy coding
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