人的情绪变化总是伴随一系列生理反应如呼吸,血压,脉搏,血管容积和腺体分泌等.和汗腺分泌有关的皮肤电反应常用作情绪变化的一种间接生理指标，是指肌体受刺激时皮肤电传导的变化,一般用电阻值及其对数或电导及其平方根表示.皮肤电（或简称为皮电反应，galvanic skin response,简写为GSR）是反映情绪变化的生理指标。许多心理现象与皮肤电平有密切关系，情绪反应会引起皮肤电平的急剧变化.因此,皮肤电可以作为情绪的生理指标.本文介绍了采用MAX32600的可穿戴皮肤电反应(GSR)仪MAXREFDES73#参考设计,包括MAXREFDES73#系统框图,AC阻抗测量框图,电路图,材料清单和PCB设计图.
The MAX32600 microcontroller is based on the industrystandardARM? Cortex?-M3 32-bit RISC CPU operatingat up to 24MHz. It includes 256KB of flash memory, 32KBof SRAM, a 2KB instruction cache, and integrated highperformanceanalog peripherals.
The MAX32600 comes in 192-ball, 12mm x 12mmCTBGA and 120-ball, 7mm x 7mm CTBGAand 108-ballWLP packages.
MAX32600优势和特性:
● Integrated AFE Enables Precision WellnessMeasurements with Minimal Discretes
• 16-Bit ADC with Input Mux and PGA
Up to 500ksps Conversion Rate
PGA with Gain of 1, 2, 4, and 8 and Bypass Mode
Differential 8:1 or Single-Ended 16:1 Input Mux
Internal Mux Inputs for Measuring VDDA3
• Internal or External Voltage ReferenceProgrammable Buffers for ADC and DACs
• Two 12-Bit DACs and Two 8-Bit DACs
• Four Operational Amplifiers
• Four Low-Power Comparators
• Four Uncommitted SPST Analog Switches
• Four Ground Switches
• Up to Eight 100mA LED Driver Pairs (Sink)
• Internal Temperature Sensor
● Secure Valuable IP and Data with Robust On-BoardTrust Protection Unit
• Trust Protection Unit for End-to-End Security
• AES Hardware Engine
• μMAA for ECDSA and RSA
• Hardware PRNG
• Fast-Erase SRAM for Secure Key Storage
● Industry’s Lowest Overall System Power IncreasesBattery Life
• 175μA/MHz Active Power Executing Code from Cache
• Less Than 1.0μA Low-Power Mode 0 (LP0) Current
• Multiple Power Management Modes to OptimizePower Consumption
• Peripheral Clock Control
• 6-Channel DMA Engine Enables IntelligentPeripheral Operation While Micro is in Sleep Mode
MAX32600主要应用:
● Wearable Medical Devices
● Pulse Oximetry Measurement
● Galvanic Skin Response Measurement
● Blood Glucose Metering
图1.MAX32600简化功能框架图
GSR measurement detects human skin impedance under different situations. A variety of events affect the skin impedance of a human body, such as changes with the ambient environment, stress from a sudden event, and sweating from physical exercises. GSR devices can be used in medical treatment, lie detection, and wellness monitoring. The MAXREFDES73# reference design is a wrist-worn GSR measurement device that monitors both skin impedance and temperature on a user’s wrist. With a mobile device for
Android, a user can monitor his or her skin resistance and temperature within 20m through the
Bluetooth low-energy (BLE) wireless interface.
The MAX32600 microcontroller is the center of the GSR device. The MAX32600 integrates all the analog front-end and other peripherals required for impedance measurements, including one 16-bit ADC with input MUX and PGA, two 12-bit DACs and two 8-bit DACs, 4 operational amplifiers (OP AMP), 4 uncommitted SPST analog switches, and internal voltage references.
The MAXREFDES73# reference design is a wearable, mobile galvanic skin response (GSR) system featuring the MAX32600 wellness measurement microcontroller. This battery-powered platform takes high-precision AC impedance measurements while consuming minimal power. The MAX32600 microcontroller features the industry-standard ARM® Cortex®-M3 32-bit RISC CPU that operates at up to 24MHz, while integrating multiple high-performance analog peripherals. Analog features include a 16-bit ADC with PGA, two 12-bit DACs, and a 16-channel multiplexer along with classic digital features such as 256KB of flash memory, 32KB of SRAM, and a 2KB instruction cache. The reference design provides a high-performance and flexible development platform, which is a foundation for many fitness and medical measurement applications, especially galvanic skin response measurement. The reference design arrives as a wrist-worn unit, powered by a LIR2032 rechargeable coin battery. A mobile application program for devices for Android™ provides the interface, and is free for download. The device communicates with a device for Android though a Bluetooth® low-energy wireless interface. Test results, hardware files, and firmware source code provide complete documentation for the design. The complete wrist-worn unit is available for purchase.
皮电反应(GSR)仪主要特性:
High precision
Integrated AFE
Low power consumption
Compact and low cost
和同类产品相比优势:
Single-chip AC impedance measurement
Wireless communication with mobile device
Portable, compact, and cost effective
皮电反应(GSR)仪应用:
AC impedance measurement
GSR measurement
图7. MAXREFDES73#系统电路图(3)
图9.MAXREFDES73#系统PCB设计图(1)
图10.MAXREFDES73#系统PCB设计图(2)
图11.MAXREFDES73#系统PCB设计图(3)
图12.MAXREFDES73#系统PCB设计图(4)
图13.MAXREFDES73#系统PCB设计图(5)
图14.MAXREFDES73#系统PCB设计图(6)
图15.MAXREFDES73#系统PCB设计图(7)
图16.MAXREFDES73#系统PCB设计图(8)
图17.MAXREFDES73#系统PCB设计图(9)
图18.MAXREFDES73#系统PCB设计图(10)
详情请见:
和
以及
与
MAX32600.pdf
MAXREFDES73_BOM_RA.pdf
MAXREFDES73_LAYOUT_RA.pdf
MAXREFDES73_SCH_RA.pdf
(编辑：mao35 来源：网络整理)
