added ecg visualisation and bpm monitoring

Author: Balaji-Avk

main.py

@@ -7,14 +7,63 @@
 HEIGHT = 64
 
 i2c = I2C(0, scl = Pin(17), sda = Pin(16), freq=200000)
-display = SSD1306_I2C(128, 64, i2c)
+display = SSD1306_I2C(WIDTH, HEIGHT, i2c)
 display.fill(0)
 
 adc = ADC(28)
+history = []  # List to store ADC readings
+peak_detected = False
+peak_count = 0
+last_peak_time = utime.ticks_ms()
+bpm=0
 while True:
-    adc_reading = round(adc.read_u16())
+    adc_reading = round(adc.read_u16() / 64)
     print(adc_reading)
-    display.text(str(adc_reading),0,14)
-    display.show()
+    # Add the ADC reading to the history
+    history.append(adc_reading)
+
+    # Keep the history length within the width of the display
+    max_history_length = WIDTH // 2
+
+    if len(history) > max_history_length:
+        history.pop(0)
+
+    # Calculate the scaling factors for the graph
+    max_value = max(history, default=0)
+    scale_x = WIDTH / (max_history_length - 1)
+    scale_y = (HEIGHT - 50) / max_value  # Adjusted for y = 35
+
     display.fill(0)
+    display.text("ECG:", 10, 0)
+
+    # Draw the line graph
+    prev_x, prev_y = None, None
+    for i, value in enumerate(history):
+        x = int(i * scale_x)
+        x2 = int((i + 1) * scale_x) if i < len(history) - 1 else int(i * scale_x)
+        y = HEIGHT - 35 - int(value * scale_y)  # Adjusted for y = 35
+
+        if prev_x is not None and prev_y is not None:
+            display.line(prev_x, prev_y, x2, y, 1)
+
+        prev_x, prev_y = x, y
+
+    display.show()
+    display.text("BPM:", 0, 55)
+    display.text(str(bpm), 35, 55)
+    display.show()
+    # Check for peaks in the ECG signal
+    if len(history) > 2 and history[-2] < history[-1] > history[-3]:
+        if not peak_detected:
+            peak_detected = True
+            peak_count += 1
+            current_time = utime.ticks_ms()
+            elapsed_time = utime.ticks_diff(current_time, last_peak_time)
+            last_peak_time = current_time
+            bpm = int(60000 / elapsed_time)
+
+            # Adjust BPM to be within the desired range
+            bpm = max(60, min(bpm, 95))
+            print(f"BPM: {bpm}")
+
     utime.sleep(0.04)