Design of Domestic Calorie Electronic-Weighing Device

摘要

Calorie Electronic-weighting device, which is used to calculate the food calorie, is addressed in this paper. Today health is the first thing to everybody, legitimacy of the food is the guarantee of health. When a food (for example beef, bread or banana) is put on the device, the user input its sort then the device will calculate and display the food calorie (Fat, Protein). This device is designed specially to diabetic, in other hand it is useful to healthy person. The device is based on a Motorola MCU (Micro controller Unit) and includes four parts, which are weighing device module, input module (keyboard), display module (LCD) and MCM (management/calculate module). The characteristic of device is it can auto calculate and display the calorie of the food in the weighting device. The weighting device includes a pressure sensor, an amplifier and A/D circuit. The low cost pressure sensor is based on reliable semiconductor technology and the Full Scale Span of it is 5kg. With the mass of the food on pressure sensor changed, a linear voltage is sent to the amplifier and A/D circuit. As a base of device, the biggest challenge is to acquire accurate data of the food, this paper will put its focus on how to calibrate the data and compensate temperature coefficient. The use of Dual slope input A/D conversion has 12 bits measuring precision, which can meet the demand of device measuring, on second thoughts it have a low cost. The management/calculate module is another important part in this device. Various sorts of food and calorie data of each food per unit are saved in the memory, as the mass data of the food is send to the MCM, it will calculate the food calorie and display in the LCD. The device is low cost, convenient, exact, it fits the demand of family.