Function graph_stream

AppData/app.py:528–728

Stream real-time GPIO voltage data based on mathematical equation Expects JSON: { 'equation': str, # Math expression (e.g., "1.65 + 1.65 * sin(x)") 'frequency': float, # Animation update frequency in Hz (1-10) 'duration': float, # Duration in seco

()

@app.route('/api/graph/stream', methods=['POST'])
def graph_stream():
    """Stream real-time GPIO voltage data based on mathematical equation
    
    Expects JSON:
    {
        'equation': str,      # Math expression (e.g., "1.65 + 1.65 * sin(x)")
        'frequency': float,   # Animation update frequency in Hz (1-10)
        'duration': float,    # Duration in seconds
        'pin': int,          # GPIO pin number
        'sample_rate': int,  # Samples per second
        'x_max': float       # X-axis maximum (time span)
    }
    """
    import math
    
    def generate():
        pwm_device = None
        start_time = time.time()
        
        try:
            data = request.get_json()
            equation_str = data.get('equation', '1.65 + 1.65 * sin(x)')
            pin = int(data.get('pin', 18))
            animation_freq = float(data.get('frequency', 1.0))  # Animation speed (1-10 Hz)
            sample_rate = int(data.get('sample_rate', 60))
            x_max = float(data.get('x_max', 10))
            
            # PWM frequency for GPIO hardware (much higher than animation frequency)
            PWM_FREQUENCY = 1000  # 1kHz is good for LEDs/bulbs
            VOLTAGE_LIMIT = 3.3
            
            # Calculate timing based on animation frequency
            update_interval = 1.0 / max(animation_freq, 0.1)  # Time between updates in seconds
            
            # Validate pin
            if pin not in VALID_PINS:
                yield f"data: {json.dumps({'error': f'Invalid pin {pin}'})}\n\n"
                return
            
            # Setup PWM on the pin with proper frequency for hardware
            try:
                cleanup_pin(pin)
                
                if GPIO_BACKEND == 'gpiozero':
                    pwm_device = PWMOutputDevice(pin, frequency=PWM_FREQUENCY)
                    log_event(f"PWM device created on pin {pin} with {PWM_FREQUENCY}Hz frequency (gpiozero)")
                elif GPIO_BACKEND == 'RPi.GPIO':
                    GPIO.setup(pin, GPIO.OUT)
                    pwm_device = GPIO.PWM(pin, PWM_FREQUENCY)
                    pwm_device.start(0)  # Start with 0% duty cycle
                    log_event(f"PWM device created on pin {pin} with {PWM_FREQUENCY}Hz frequency (RPi.GPIO)")
                else:  # mock
                    pwm_device = GPIO.PWM(pin, PWM_FREQUENCY)
                    pwm_device.start(0)
                    log_event(f"PWM device created on pin {pin} with {PWM_FREQUENCY}Hz frequency (mock)")
                
                pwm_devices[pin] = {
                    'device': pwm_device,