calculators/tap-tempo-calculator.html at master · guyru/calculators · GitHub

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<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Tap Tempo BPM Calculator - Real-time Beat Detection</title>
    <meta name="description" content="Tap tempo BPM calculator with configurable sample size and timeout. Detect beats per minute in real-time by tapping a button. Perfect for musicians and DJs.">
    <meta name="keywords" content="tap tempo, bpm calculator, beats per minute, tempo calculator, music tempo, rhythm calculator, metronome">
    <meta name="author" content="guyru">

    <!-- Open Graph / Facebook -->
    <meta property="og:type" content="website">
    <meta property="og:url" content="https://guyru.github.io/calculators/tap-tempo-calculator.html">
    <meta property="og:title" content="Tap Tempo BPM Calculator - Real-time Beat Detection">
    <meta property="og:description" content="Tap tempo BPM calculator with configurable sample size and timeout. Detect beats per minute in real-time by tapping a button.">

    <!-- Twitter -->
    <meta property="twitter:card" content="summary">
    <meta property="twitter:url" content="https://guyru.github.io/calculators/tap-tempo-calculator.html">
    <meta property="twitter:title" content="Tap Tempo BPM Calculator - Real-time Beat Detection">
    <meta property="twitter:description" content="Tap tempo BPM calculator with configurable sample size and timeout. Detect beats per minute in real-time by tapping a button.">

    <link rel="stylesheet" href="shared.css">
    <style>
        .tap-button {
            width: 100%;
            min-height: 200px;
            font-size: 1.5rem;
            font-weight: 600;
            background: var(--color-primary);
            color: white;
            border: none;
            border-radius: var(--radius-md);
            cursor: pointer;
            transition: all 0.15s ease;
            margin: var(--spacing-md) 0;
            display: flex;
            align-items: center;
            justify-content: center;
            user-select: none;
            -webkit-tap-highlight-color: transparent;
            letter-spacing: 0.025em;
        }

        .tap-button:hover {
            background: var(--color-primary-hover);
        }

        .tap-button:active,
        .tap-button.active {
            transform: scale(0.98);
            background: var(--color-primary-hover);
        }

        .bpm-display {
            text-align: center;
            margin: var(--spacing-md) 0;
        }

        .bpm-value {
            font-size: 3rem;
            font-weight: 700;
            color: var(--color-text);
            margin: var(--spacing-xs) 0;
            letter-spacing: -0.025em;
        }

        .bpm-label {
            font-size: 1rem;
            color: var(--color-text-secondary);
            margin-bottom: var(--spacing-xs);
            font-weight: 500;
        }

        .tap-count {
            font-size: 0.875rem;
            color: var(--color-text-secondary);
            margin-top: var(--spacing-xs);
        }

        .settings-grid {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: var(--spacing-md);
            margin-bottom: var(--spacing-md);
        }

        .reset-button {
            background: var(--color-surface);
            color: var(--color-text);
            border: 1px solid var(--color-border);
            padding: 0.625rem 1.25rem;
            border-radius: var(--radius-md);
            cursor: pointer;
            font-size: 0.9375rem;
            transition: all 0.15s ease;
            margin-top: var(--spacing-xs);
            font-weight: 500;
        }

        .reset-button:hover {
            border-color: var(--color-primary);
            color: var(--color-primary);
        }

        @media (max-width: 768px) {
            .settings-grid {
                grid-template-columns: 1fr;
                gap: var(--spacing-sm);
            }

            .tap-button {
                min-height: 150px;
                font-size: 1.25rem;
            }

            .bpm-value {
                font-size: 2.5rem;
            }
        }
    </style>
</head>
<body>
    <div class="calculator-container">
        <div class="header">
            <h1>Tap Tempo BPM Calculator</h1>
            <p>Tap the button to detect beats per minute in real-time</p>
        </div>

        <button class="tap-button" id="tapButton"
                aria-label="Tap this button to the beat to calculate BPM">
            TAP HERE
        </button>

        <div class="bpm-display">
            <div class="bpm-label">Beats Per Minute</div>
            <div class="bpm-value" id="bpmValue" aria-live="polite">--</div>
            <div class="tap-count" id="tapCount" aria-live="polite">Tap to start</div>
            <button class="reset-button" id="resetButton" aria-label="Reset all taps and start over">
                Reset
            </button>
        </div>

        <form id="calculatorForm">
            <div class="settings-grid">
                <div class="form-group">
                    <label for="sampleSize">Sample Size</label>
                    <input type="number" id="sampleSize" min="2" max="20" value="5"
                           aria-describedby="sampleSizeHelp" aria-label="Number of taps to average for BPM calculation">
                    <div class="help-text" id="sampleSizeHelp">Number of taps to average (smoothing factor)</div>
                </div>

                <div class="form-group">
                    <label for="timeout">Timeout (seconds)</label>
                    <input type="number" id="timeout" min="1" max="30" value="5"
                           aria-describedby="timeoutHelp" aria-label="Seconds before clearing tap history">
                    <div class="help-text" id="timeoutHelp">Seconds of inactivity before clearing taps</div>
                </div>
            </div>
        </form>

        <div class="github-links">
            <a href="index.html" aria-label="Back to calculators index">← Back to Calculators</a>
            <a href="https://github.com/guyru/calculators" target="_blank" rel="noopener noreferrer">View Source</a>
            <a href="https://github.com/guyru/calculators/issues" target="_blank" rel="noopener noreferrer">Report Issue</a>
        </div>
    </div>

    <script>
        class TapTempo {
            constructor(sampleSize = 5, timeoutSeconds = 5) {
                this.sampleSize = sampleSize;
                this.timeout = timeoutSeconds * 1000; // Convert to milliseconds
                this.timestamps = [];
            }

            updateSettings(sampleSize, timeoutSeconds) {
                this.sampleSize = sampleSize;
                this.timeout = timeoutSeconds * 1000;
                // Clear timestamps when settings change to avoid inconsistency
                this.timestamps = [];
            }

            tap() {
                const now = Date.now();

                // Remove timestamps older than sample size
                if (this.timestamps.length >= this.sampleSize) {
                    this.timestamps = this.timestamps.slice(0, this.sampleSize - 1);
                }

                // Reset timestamps if the duration since the last timestamp exceeds the timeout
                if (this.timestamps.length > 0) {
                    const lastTimestamp = this.timestamps[0];
                    if (now - lastTimestamp > this.timeout) {
                        this.timestamps = [];
                    }
                }

                // Store the timestamp at the beginning of the array (most recent first)
                this.timestamps.unshift(now);

                // Calculate average duration between taps
                if (this.timestamps.length > 1) {
                    const totalDuration = this.timestamps[0] - this.timestamps[this.timestamps.length - 1];
                    const averageDuration = totalDuration / (this.timestamps.length - 1);
                    const bpm = 60000 / averageDuration; // Convert to BPM

                    return {
                        bpm: bpm,
                        tapCount: this.timestamps.length
                    };
                }

                return {
                    bpm: null,
                    tapCount: this.timestamps.length
                };
            }

            reset() {
                this.timestamps = [];
            }
        }

        // DOM elements
        const tapButton = document.getElementById('tapButton');
        const bpmValue = document.getElementById('bpmValue');
        const tapCount = document.getElementById('tapCount');
        const resetButton = document.getElementById('resetButton');
        const sampleSizeInput = document.getElementById('sampleSize');
        const timeoutInput = document.getElementById('timeout');

        // URL fragment state management
        function parseHash() {
            const hash = window.location.hash.slice(1);
            const params = {};
            if (hash) {
                hash.split('&').forEach(part => {
                    const [key, value] = part.split('=');
                    if (key && value !== undefined) {
                        params[decodeURIComponent(key)] = decodeURIComponent(value);
                    }
                });
            }
            return params;
        }

        function updateHash() {
            const params = {};
            if (sampleSizeInput.value && sampleSizeInput.value !== '5') {
                params.sampleSize = sampleSizeInput.value;
            }
            if (timeoutInput.value && timeoutInput.value !== '5') {
                params.timeout = timeoutInput.value;
            }

            const hashString = Object.entries(params)
                .map(([k, v]) => `${encodeURIComponent(k)}=${encodeURIComponent(v)}`)
                .join('&');
            history.replaceState(null, '', hashString ? '#' + hashString : window.location.pathname);
        }

        function loadFromHash() {
            const params = parseHash();
            if (Object.keys(params).length === 0) return;

            if (params.sampleSize) sampleSizeInput.value = params.sampleSize;
            if (params.timeout) timeoutInput.value = params.timeout;
        }

        // Load settings from URL hash
        loadFromHash();

        // Initialize the tap tempo calculator with current settings
        let tapTempo = new TapTempo(
            parseInt(sampleSizeInput.value) || 5,
            parseInt(timeoutInput.value) || 5
        );

        // Handle tap button clicks
        tapButton.addEventListener('click', function() {
            const result = tapTempo.tap();

            if (result.bpm !== null) {
                bpmValue.textContent = Math.round(result.bpm); // Round to integer
                tapCount.textContent = '';
            } else {
                bpmValue.textContent = '--';
                tapCount.textContent = result.tapCount === 1 ? 'Tap again for BPM' : 'Keep tapping';
            }
        });

        // Handle reset button
        resetButton.addEventListener('click', function() {
            tapTempo.reset();
            bpmValue.textContent = '--';
            tapCount.textContent = 'Tap to start';
        });

        // Handle settings changes
        function updateSettings() {
            const sampleSize = parseInt(sampleSizeInput.value);
            const timeout = parseInt(timeoutInput.value);

            if (sampleSize >= 2 && sampleSize <= 20 && timeout >= 1 && timeout <= 30) {
                tapTempo.updateSettings(sampleSize, timeout);
                // Reset display when settings change
                bpmValue.textContent = '--';
                tapCount.textContent = 'Tap to start';
                updateHash();
            }
        }

        sampleSizeInput.addEventListener('input', updateSettings);
        timeoutInput.addEventListener('input', updateSettings);

        // Add keyboard support for spacebar tapping
        document.addEventListener('keydown', function(event) {
            if (event.code === 'Space') {
                event.preventDefault(); // Prevent page scrolling
                tapButton.classList.add('active');
                tapButton.click();
            }
        });

        document.addEventListener('keyup', function(event) {
            if (event.code === 'Space') {
                tapButton.classList.remove('active');
            }
        });
    </script>
</body>
</html>