Physics Lab Equipment

LEMI-65 Pressure Sensor and Measurement of Heart Rate & Blood Pressure

LEMI-65 Pressure Sensor and Measurement of Heart Rate & Blood Pressure


Pressure is a non-electric physical quantity. Besides of the traditional method for gas pressure measurement using pointer pressure gauges, the use of pressure sensors to convert gas pressure into an electric quantity to achieve digital display and monitoring is also applicable. 

LEMI-65, Pressure Sensor Characteristics and Measurement of Human Heart Rate and Blood Pressure, is a specially designed teaching apparatus for medical undergraduates or graduates to learn and master the characteristics of gas pressure sensors and their applications. 

This apparatus uses a MPS3100 pressure sensor to convert the gas pressure into voltage and uses an amplifier and a digital voltmeter to construct a digital pressure gauge, then uses a standard pressure gauge to calibrate its readings. Considering that the apparatus mainly measures human blood pressure, its measurement range is set at 0 - 32 kPa (240 mmHg). Due to the excellent linearity of the MPS3100 pressure sensor (0.3% FS), the constructed digital pressure gauge has good accuracy. 

This apparatus uses a quantitative gas pump-in device, which enables to prove Boyle’s gas law experimentally. Combined with pulse sensor, blood pressure cuff, squeeze ball and medical stethoscope, the body's pulse wave, heart rate and blood pressure can be measured. By conducting experiments using this apparatus, students can achieve following objectives:

1. Understand the working principle of the gas pressure sensor and test its characteristics.

2. Use gas pressure sensor, amplifier and digital voltmeter to construct a digital pressure gauge and calibrate it with a standard pointer pressure gauge.

3. Understand the principle of measuring human heart rate and blood pressure, use pulse sensor to measure pulse waveform and heartbeat frequency, and use the constructed digital pressure gauge to measure human blood pressure.

4. Verify Boyle’s law of the ideal gas. (Optional)

5. Use slow scanning long afterglow oscilloscope (need to be purchased separately) to observe the body pulse waveform and analyze the heart beat, estimate heart rate, blood pressure and other parameters. (Optional)

The instruction manual contains experimental configurations, principles, step-by-step instructions, and examples of experiment results. Please click Experiment Theory and Contents to find more information about this apparatus.

Main Specifications

DC regulated power supply5 V 0.5 A (×2)

Digital voltmeter

Range: 0 ~ 199.9 mV, resolution 0.1 mV

Range: 0 ~ 1.999 V, resolution 1 mV

Pointer pressure gauge0 ~ 40 kPa (300 mmHg)
Smart pulse counter0 ~ 120 ct/min (data hold 10 tests)
Gas pressure sensorRange 0 ~ 40 kPa, linearity ± 0.3%
Pulse sensorHK2000B, analog output
Medical stethoscopeMDF 727

Parts List  

Main unit1
Pulse sensor1
Medical stethoscope1
Blood pressure cuff1
100 mL syringe2
Rubber tubes and tee 
1 set
Connection wires12
Power cord1
Instruction manual1


Schematic of panel drawing

(Click figure to enlarge)

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