基于加速度传感器的坠落检测系统.doc

目录
摘要: 1
0 前言 2
1单片机简介 2
STC89C52引脚及其功能 3
中断系统 5
定时器/计数器 7
串行口及IIC总线接口 8
2 ADXL345加速度传感器简介 9
ADXL345工作原理 9
ADXL345内部寄存器介绍 10
ADXL345通过IIC总线方式连接简介 11
3 LCD1602液晶简介 12
主要接口及存储器映射 12
基本操作时序 13
4 系统分析与实现 13
硬件连接 14
程序流程 15
部分程序代码 16
系统运行说明 20
5 结论 20
参考文献 21
基于加速度传感器的坠落检测系统
(河南大学物理与电子学院,河南开封,475004)
摘要:
硬盘在读写数据时,磁头与碟片之间的间距很小,同时碟片转速也很高,因此,外界的震动很容易就可能对硬盘造成很大的伤害,造成数据丢失的后果。为提高耐用性我们必须能够可靠的检测到“自由落体”坠落,保证硬盘磁头在碰撞到来前停止工作,从而避免或减轻硬盘可能受到的损坏。
ADXL345是一款非常适合移动设备的加速度传感器,低功耗、高分辨率,可通过SPI或IIC数字接口访问数字输出数据。它可以检测静态或动态重力加速度,自由落体检测功能可以检测器件是否正在掉落。
这里利用ADXL345三轴加速度计检测重力加速度的方法,检测系统状态,模拟硬盘坠落保护系统。同时,根据三轴测量结果,计算各方向的倾斜角度,实现对系统姿态的感知。
关键词:
MEMS;ADXL345;单片机;坠落检测;
The Fall sensing System Based on Digital Accelerometer
Gao Xiang
(School of Physics and Electronics, Henan University, Henan Kaifeng 475004, China)
Abstract:
The space between the read head and disc is so small while hard disk is reading or writing data, the speed is very high in the same time, a little shock may cause considerable damage to the hard disk and destroy data. We must detect Free-fall reliable to ensure the read head stop reading or writing data before the es, in order to avoid or less damaging,
The ADXL345 is a small, thin, ultralow power accelerometer with high resolution, which is well suited for mobile device applications, its digital output data is accessible through erther a SPI or IIC digital measures the static acceleration of gravity and dynamic acceleration resulting from motion or shock. Free-fall sensing detects if the device if falling.
By the way of check the measurements of acceleration, to judge whether the system is falling down, we can simulate the fall sensing system of hard disk. Similar, comparing the acceleration on any axis and calculate the inclination changes, to realize the detection and control of the system.
Key words:
MEMS;ADXL345;Microcontrollers;Fall sensing;
0 前言
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