Design of Embedded Intelligent Insulin Pump Based on LPC2478

Overview

Currently, one diabetic patient dies from complications every 10 seconds worldwide, and two new diabetic patients are diagnosed in the same 10 seconds. The total number of people affected by diabetes is about 246 million, and it is expected that the number of diabetic patients will rise to 380 million in the next 20 years. Diabetes is a lifelong metabolic disease. If it can be effectively controlled, patients can live with the disease for life without affecting their work and life. If it is not properly controlled, it will lead to serious complications such as cardiovascular disease, dyslipidemia, blindness, renal failure and amputation.

Existing insulin pumps can only inject insulin, but lack the ability to monitor blood sugar in patients. It is a "semi-open loop" system. With the improvement of the national economy and people's living standards, patients' demand for medical equipment is growing, and their performance requirements are also increasing. Therefore, it is necessary for us to design an intelligent insulin pump based on an embedded system, which has two functions of injection and monitoring, to achieve true "closed loop" control and minimize the inconvenience brought by diabetes to patients' lives. And it is small in size, low in price, and can meet the health needs of the majority of diabetic patients. Therefore, the development of intelligent insulin pumps has broad application and market prospects.

System Implementation

The embedded intelligent insulin pump mainly includes the main processor, power supply and reset, LCD touch screen, pump driver module and signal acquisition module. With the help of the highly integrated LPC2478 microcontroller, the chip integrates USB controller, Ethernet interface, PWM, ADC and convenient LCD display interface. The USB is used to transmit data, the ADC is used to collect blood sugar signals, the PWM function is used to drive the pump, the LCD interface provides the human-computer interaction display part, and the Ethernet interface will provide network service functions.

Since the current insulin pump is only a device for inputting insulin, it cannot automatically sense the blood sugar concentration in the user's body, nor can it automatically control blood sugar to normal. Therefore, this design adds a blood sugar monitoring function based on the original function of the insulin pump, collects blood sugar values ​​at intervals, and adjusts the temporary injection volume in real time through comparison. The LCD touch screen can be used to easily query blood sugar values ​​and historical injection records. USB and Ethernet can exchange data with PCs and send them to doctors through the network. Doctors use blood sugar charts to formulate corresponding treatment plans, and can reset the insulin injection volume based on the treatment plan. The use of a friendly human-computer interaction interface brings great convenience to diabetic patients and helps patients get rid of the distress of inconvenience in life.

Based on the original function of insulin pump, this system adds blood sugar monitoring function, which truly plays the role of artificial pancreas. The stored data is plotted into blood sugar graph and transmitted to doctors through the network so that doctors can formulate corresponding treatment plans, and finally realize the integrated treatment of individuals, instruments and medical institutions.

The hardware platform uses a self-drawn PCB board, including six parts: microcontroller module, motor drive module, LCD display module, signal acquisition and amplification circuit, USB interface module and Ethernet interface module. The hardware schematic diagram is shown in Figure 1.

Microprocessor module

The microprocessor module uses the LPC2478 chip with ARM7 TDMI-S as the core. Its operating voltage range is 3.3V~3.5V, and it has 512kB on-chip high-speed Flash memory, 1 external memory controller (EMC), 1 LCD controller, 1 10/100 Ethernet media access controller (MAC), 1 USB full-speed Device/Host/OTG controller, 1 10-bit ADC and 1 PWM unit and other on-chip resources.

LCD Display Module

Since the LCD controller is integrated in the LPC2478 microcontroller, the system design is simplified, the development difficulty is reduced, and a low-cost, low-power and efficient LCD display solution is provided. The LCD interface circuit is shown in Figure 2, which is a 4-wire touch screen interface circuit based on ADS7843.

Motor drive module

The micro pump drive circuit adopts ROHM's H-bridge driver, whose low voltage and convenient PWM signal (20kHz~100kHz) input controls the motor speed, providing a high efficiency and low power consumption solution for the system.