怀孕监视器采用监测荷尔蒙水平来实现, 荷尔蒙水平监测由三种标准方法:尿液, 唾液和体温.每种检测需要模拟前端来实现.本文介绍了采用Cypress公司的CY8C38系列来开发怀孕监视器的确具体方案,方框图以及CY8C38 系列特性,框图,CY8C38系列典型应用电路图以及CY8CKIT-001 PSoC开发板主要特性,电路图和材料清单.
Fertility Monitors are devices that monitor fertility levels by monitoring hormone levels. A fertility monitor may analyze hormone levels in bodily fluids, resistance in bodily fluids, basal temperature, or a combination of these methods. There are three standard methods for monitoring hormone levels:
Urine: Tests for luteinizing hormone surge
Saliva: Detects changing electrolyte levels
Temperature: Monitors basal body temperature to predict cycles
Each of these sensing methods require an analog front end (AFE) to perform the necessary measurements. Fertility Monitors are battery powered devices so active power consumption and sleep current are important considerations. A fertility monitor also includes a display, memory for storage of fertility reading history, serial communication such as USB. A touchscreen or capsense user interface may also be seen in fertility monitors.
PSoC® 3 and PSoC 5 provide a scalable platform which provides all the requisite circuitry to provide a configurable Fertility Monitor on Chip, including:
• High precision Analog front end, including a 0.1% accurate Voltage reference and up to 20 bits of resolution
• Circuitry for sequencing and driving LED for optical measurement of the test strip and the circuitry for reading the photodiode to create a full optical measurement system
• LCD direct drive and control
• Low active and sleep mode power consumption, with full operation down to 0.5V
• CapSense fully integrated
• FS USB
• On chip EEPROM
图1. 怀孕监视器框图
PSoC®3 具有独特的可配置模块阵列,是真正的系统级解决方案,能够通过单个芯片提供 MCU、存储器、模拟和数字外设功能。
CY8C38 系列提供了一种新型的信号采集、信号处理和控制方法,并具有高精度、高带宽和高灵活性等特点。其模拟功能涵盖了从热电偶信号(接近直流电压)到超声波信号的广泛信号范围。CY8C38 系列可以处理数十个数据采集通道以及每个 GPIO 引脚上的模拟输入。CY8C38 系列还是一个高性能的可配置数字系统,具有 USB、多主控 I2C 以及 CAN 等接口。除了通信接口之外,CY8C38 系列还具有易于配置的逻辑阵列,至所有 I/O 引脚的灵活路由,以及高性能的单周期 8051 微处理器内核。通过分层式电路图设计输入工具 PSoC® Creator™,设计人员可以使用包含众多预建组件和布尔基元的资料库,轻松创建系统级设计。使用 CY8C38 系列不仅可以实现模拟和数字材料表的集成,而且只需通过简单的固件更新,即可轻松纳入最新的设计变更。
CY8C38 系列特性: