Electronic enthusiasts core tips: When designing medical portable monitors, in addition to using smaller, lighter and satisfying CPU cards that support LCD monitors, the bumps of ambulances, and vibrations when running fast are the issues that design engineers must consider. This article will discuss the specific scheme of designing a medical portable monitor using an embedded CPU card.
Software platform: DOS operating system, application software.
Hardware platform: AC-DC power supply, battery, micro printer, ECG collection module, blood oxygen collection module, blood pressure collection module, etc., multi-serial port expansion card, TTL interface LCD display (resolution 800 * 600 or 6? 0 * 480) ), Embedded CPU control card.
1. The functions realized by the software are not studied in detail. The rough concept is that the application software sends various collection instructions through the CPU on the basis of DOS, and through multiple serial port cards to each collection module, collects human body signals, and uses the collected signals with various This algorithm changes into a variety of information that we can identify and display it on the LCD. Then there is the realization of data communication with the central monitoring. Most of them are serial communication. Most of them use the serial port 1 or 2 of the motherboard.
2. The choice of hardware platform and the reason for this choice
Power supply: Because the ambulance is 12V DC, and the room is usually only 220V AC, and the battery is used in the outdoor and hospital corridors, the power supply design of the monitor takes into account AC and DC and the low power consumption of the battery.
Collection module: It is used to measure various parameters of the human body, including ECG collection module, blood oxygen collection module, blood pressure collection module, etc. It is generally collected through serial port.
Serial port expansion card: If you choose the PC104 motherboard (PCM-3486), you must choose a PC / 104 multi-serial card to collect more human parameters. Liquid crystal displays are small in size and light in weight so that they can be portable. Everyone knows what an ordinary display is.
Now let ’s talk about CPU cards. Above we have said that we need to be portable. For portability we use LCD, so we need to use smaller, lighter and satisfying CPU cards that support LCD. This reminds us of PC / 104 motherboard Of course, it is simple but small in size and can not meet the needs here. The bumps of the ambulance and the vibrations when running by hand are the issues we must consider. At this time, we need products with a very high degree of integration. Furthermore, in many occasions (outdoors, hospital corridors) we can only use batteries, the battery power is limited, so we must consider that the power consumption of the CPU card can not be too high, PCM3486 using low-power CPU can well guarantee the medical organization The specified requirement for normal operation for 2 hours when only batteries are used-"very satisfied". The PCM3486 onboard electronic hard disk meets the characteristics of small size, light weight, anti-vibration, long read and write times, low power consumption, and no problems.
Due to the difficulty in supplying liquid crystal display, there will be the problem of frequent model replacement. Of course, the color types are all true colors. PCM3486 can support more than 98% of the true color LCDs with a resolution below 800 * 600 (including 800 * 600). Good solution to the supply contradiction. As for the mini printer, it is not much different from ordinary printers in terms of usage except for the appearance and size. It is sufficient to have a compatible parallel port. The monitoring software is a software system that requires high real-time performance. When there are many parameters (basically 6 parameters include ECG, blood pressure, blood oxygen, pulse, body temperature, and breathing. Most refer to other than the basic 6 parameters Additional parameters such as the measurement of CO2 content in the lung) When the resolution of the LCD display is 800 * 600, in order to better reflect the real-time nature of the software, the relatively fast 486-level board PCM3486 can achieve the best results. Some people will say that the microcontroller is cheap and low power consumption can be made into a small board. Why not use it here? Obviously this is true but it supports LCD. In terms of processing complex algorithms and real-time program, it can hardly achieve monitoring. The required functions are hard to find perfect applications. On the contrary, PCM3486, a first-class product with a good price-performance ratio, will make you more comfortable on the basis of ensuring that you can use it.
3. Specific practices
Everything can be installed, the CPU card is connected to the LCD display, printer, power supply and battery, the installation program is connected to the on-board electronic hard disk, the embedded CPU module bus is connected to the multi-serial card, and the multi-serial card is connected to each acquisition module. Power on OK!
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