A medical human basic parameter Tester design (1)

1 Introduction

Research is a fundamental instrument of human body, can measure temperature, pulse and respiratory parameters such as the interval.

These parameters and the record is the most basic nursing technique, the technology is more mature. But ordinary single large multifunctional portable devices, accuracy is not high, and can only be used as a temporary measure to track patients throughout the treatment process: the hospital's medical equipment used to provide a high level of accuracy, and full-featured, but too professional to use and high prices lead to their market requirements. Given these shortcomings, the system has the following significance: ① adoption of an instrument will human parameters together in real time measurements to improve measuring instruments of integrated and convenience. ② measurement using a fully automated way, through the various parameters you can set a threshold on the measure exceeds the threshold parameters automatically gives the instructions. This portable, precision and can record the body parameter Tester has a high scientific value and social significance.

Comparative analysis of 2 designs

Measurement of body temperature 2.1

Programme l: the use of digital temperature sensors.

Digital temperature sensor internal integrated temperature sensor and a/d converter, can convert temperature directly into digital content into the microprocessor.

Scenario 2: using analog temperature sensor.

That is, the output voltage can be continuously changing analog temperature sensors, and high-precision A/D converter analog voltage output is converted to digital.

Scenario 1 is easy to implement, but would like to realize high-precision temperature measurement, the cost is relatively high.

And programme 2 as the output voltage of the sensor can be continuous change, simply raise A/D converter accuracy can substantially improve the accuracy of the temperature measurement, the system uses the scenario 2.

2.2 breathing interval measurement

Scenario 1: human body chest of ups and downs through the expansion of elastic material to reflect, elastic material expansion driven sliding vane sliding on the resistance wire, change its both ends of the resistance.

Through the resistor divider methods enable voltage changes and ups and downs of the chest, the ultimate realization of breathing interval measurement. This programme on elastic material and resistance wire, and the bundled ways has strict requirements.

Scenario 2: uses a pressure sensor.

His installation as shown in Figure 1. Diagram of scallops selection length deformation small wire and strap on fixed a pressure sensor, pressure fluctuations cause pleural cavity sensor pressure changes, through the acquisition of electrical signals in the sensor output timeline snapping pleural undulating trend, you can achieve respiration measurement interval time. The installation is simple, more adapted to the requirements of the portable device.

To sum up, the system selects scenario 2.

2.3 pulse measurement

Option 1: adopt photoelectric sensor.

The finger is placed in between the light source and photodetector, when your finger on the pulse of a beating in the light of changes in blood, photodetector received light intensity. To get the pulse beat of change of electrical signals, but the signal is very weak extraction.

Scenario 2: using piezoelectric sensors.

In the wrists installation sensitivity high piezoelectric sensors, the beating pulse pressure signals converted to electrical signals for pulse measurement. But the cost is relatively high.