物联网AI MicroPython传感器学习 之 手指侦测心跳传感器

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一、产品简介

手指侦测心跳传感器是通过LED和光电晶体管监测手指血压脉冲，来判断人的心脏跳动。其结构简单成本低廉，只能是做一些实验和学习相关的知识（没有医疗实用价值）

引脚定义

• -: GND
• +: 3.3V
• S: 模拟信号输出

二、软件接口

FHEARTBEAT(adcObj) - 创建FHEARTBEAT驱动对象

• 函数原型:

fheartbeatObj = FHEARTBEAT(adcObj)

• 参数说明:

• 返回值:

创建对象成功，返回FHEARTBEAT对象；FHEARTBEAT对象创建失败，抛出Exception

• 示例代码:

from machine import ADC,Pin
import fheartbeat

adcObj = ADC(Pin(32))
fheartbeatDev = fheartbeat.FHEARTBEAT(adcObj)
print("fheartbeat  Init...")
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• 输出:

fheartbeat  Init...
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getVoltage - 测量手指侦测心跳电压值

• 函数功能:

量测手指侦测心跳电压值并返回测量结果

• 函数原型:

FHEARTBEAT.getVoltage()

• 参数说明:
  无
• 返回值:

成功返回手指侦测心跳电压值测量结果（数据类型：浮点型；单位：mV）；失败抛出Exception

• 示例:

from machine import ADC,Pin
import fheartbeat

adcObj = ADC(Pin(32))
fheartbeatDev = fheartbeat.FHEARTBEAT(adcObj)
print("fheartbeat  Init...")

voltage = fheartbeatDev.getVoltage()
print("voltage: %d"%voltage)
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• 输出:

Testing fheartbeat  ...
voltage: 800.0
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三、接口案例

• 代码:

# Python代码
import utime                         # 延时API所在组件
from machine import ADC,Pin
import fheartbeat

i = 0
trip = {}
adcObj = ADC(Pin(32))
fheartbeatDev = fheartbeat.FHEARTBEAT(adcObj)
print("fheartbeat  Init...")
while 1:
    voltage = fheartbeatDev.getVoltage()
    trip[i] = voltage
    i  = i + 1
    if i == 50:
        i = 0
        print("trip:",trip)
    utime.sleep_ms(10)
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• 输出：

...
Testing fheartbeat  ...
trip: {0: 3719, 1: 3720, 2: 3719, 3: 3720, 4: 3717, 5: 3734, 6: 3726, 7: 3732, 8: 3730, 9: 3732, 10: 3724, 11: 3724, 12: 3732, 13: 3732, 14: 3734, 15: 3730, 16: 3726, 17: 3719, 18: 3734, 19: 3728, 20: 3724, 21: 3728, 22: 3732, 23: 3720, 24: 3732, 25: 3724, 26: 3720, 27: 3720, 28: 3724, 29: 3719, 30: 3717, 31: 3726, 32: 3720, 33: 3722, 34: 3719, 35: 3734, 36: 3722, 37: 3717, 38: 3722, 39: 3720, 40: 3719, 41: 3720, 42: 3711, 43: 3717, 44: 3734, 45: 3724, 46: 3722, 47: 3720, 48: 3724, 49: 3717}
trip: {0: 3732, 1: 3720, 2: 3720, 3: 3713, 4: 3719, 5: 3719, 6: 3717, 7: 3720, 8: 3717, 9: 3717, 10: 3719, 11: 3717, 12: 3724, 13: 3724, 14: 3720, 15: 3720, 16: 3720, 17: 3724, 18: 3713, 19: 3719, 20: 3719, 21: 3715, 22: 3713, 23: 3713, 24: 3720, 25: 3717, 26: 3713, 27: 3717, 28: 3720, 29: 3709, 30: 3722, 31: 3715, 32: 3719, 33: 3719, 34: 3715, 35: 3709, 36: 3724, 37: 3719, 38: 3717, 39: 3717, 40: 3719, 41: 3711, 42: 3728, 43: 3720, 44: 3719, 45: 3724, 46: 3717, 47: 3717, 48: 3717, 49: 3732}
...
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四、通信协议

主控芯片通过ADC读取手指侦测心跳传感器的电压值数据。

五、工作原理

当手指放在发射器与接收器之间，红外发射LED发射的光将穿过手指，到被接收器接收。而血压会随着脉搏变化，导致红外接收器接收到的光通量也会随之变化，因此可以通过红外光接收的情况来统计监测心跳。其大概的电原理示意图如下：

参考文献及购买链接

[1] 商品链接