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优右仰
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1 實驗一報告報告繳交期限 : 10 月 9 日 ( 二 )11:00 Report content ( 報告內容 ) 1. Complete three experiment reports ( 三份實驗紀錄表格檔案 ) 2. Complete additional questions 請合併成一個 PDF 檔案寄到助教的信箱 (belab.ntu@gmail.com), 主旨標明組別及實驗序

2 行事曆

3 期中報告期中報告 (Group) 題目 : 生醫工程相關皆可, 例如 : 生理電信號原理醫學影像等在決定題目之前請先跟助教討論, 確定報告的題目範圍是否會太廣而無法負荷要求 : 每組報告時間約 15 分鐘, 提問 5 分鐘 ( 有提問者另外加分 ) 註 : 期中報告結束的一個禮拜一定要給我們發票 11/06 截止

4 實驗二 : 生理電信號量測電路設計與實現

5 Introduction 根據實驗一選定的生理電信號繼續對這種信號作量測電路的設計在操作實驗一的時候你發現什麼? 應該很順利都可以量到信號是否跟文獻做過比較? 自行設計電路不同的生理電信號其設計方式也會不同利用 NI ELVIS / Arduino + Android APP Invertor 實現

6 Experiment Overview Design circuit(s) for bio-signal detection 1. ECG 2. EMG 3. EEG PART I Digitize the detected waveform (ADC) Transmit to the self-designed APP via bluetooth APP: Waveform display oscilloscope PART II

7 PART I: 量測電路 Circuit Design for Bio-Signal Detection

8 PARTI: Introduction Characteristics of ECG, EMG, and EEG waveform Based on the findings from experiment 1 and published reports/journals Examples: amplitude, center frequency and bandwidth Design your own detection circuit(s) Use NI ELVIS II to test the effectiveness of your circuit Energy efficient circuit

9 Simplified Layout of Detection Circuit Signal Inputs (3 Leads) ~µv ~mv Pre-Amplification Filter (LPF / HPF / NOTCH / BPF) Display Post-Amplification ADC Circuitry Voltage Level Shifter Signal Output (0V 5V)

10 Noise Figure 如何達成最高的增益最低的雜訊指數? Noise Figure

11 Pre Amplifier Lead II 三點 ECG( 正極負極接地 ) OP 放大器? 雙極訊號轉為單極訊號差動放大器

12 Buffer 使前一級電路不受負載影響 R=

13 儀表放大器差動放大器儀表放大器 (INA128) 在正負輸入端都加上 unit gain buffer 非常低直流偏移低漂移低雜訊非常高的開迴路增益非常大的共模拒斥比高輸入阻抗

14 市電市電, 又稱壁上電源交流電輸電網, 為城市裡主要提供市民使用的電源一般家庭用電為 AC 100~125V 60Hz 正弦波該如何解決 60Hz 的訊號影響? Notch filter

15 訊號頻率範圍從頻譜以及文獻看訊號主要的頻帶在哪設計適當的濾波器高通濾波器 (DC offset 低頻雜訊) 低通濾波器 ( 高頻雜訊 ) Notch filter( 市電 )

16 Low Pass Filter V out V in R V out 1 R + sc V out V in = f c = 1 2πRC = V out 1 sc = V in R src = RC s + 1 RC C = 0.33uF R = 10k Cut off frequency = 48Hz

17 Low Pass Filter 頻率響應 Gain = 1 RC s + 1 RC 1 2πRC 參考電路 ( 二階低通濾波器 ) Sallen-Key Lowpass filter

18 High Pass Filter V out V in = V out 1 R sc 1 V out R + sc = scv in V out = src V in 1 + src = s s + 1 RC f c = 1 2πRC

19 High Pass Filter 頻率響應 Gain = s s + 1 RC 1 2πRC 參考電路 ( 二階低通濾波器 ) Sallen-Key highpass filter

20 Notch Filter Twin-T notch Center reject frequency er.php

21 Notch Filter Wien Bridge Notch Filter f c = 1 2πRC

22 Post Amplifier 基本 OP 放大器 non-inverting amplifier Gain=1+R2/R1

23 Level Shifter Arduino 接收電壓範圍 0~5V 不准送負的電壓進去 Arduino V out = V R2 R1 V + = R3V2 R3 + R4 + R4V1 R3 + R4 透過電阻與電源的分壓讓心電圖的訊號平移至 0V 以上

24 Analog to Digital Converter 如何將 0~5V 電壓轉換為數位訊號? 8bits ADC 2^8=256 0~255 例如輸入電壓 3V 255/5*3=153(DEC)= (BIN)

25 Digital Signal ADC (Analog-Digital-Convertor) Nyquist sampling frequency Quantization error Offset error (LSB) Digital filter: MATLAB Built-in functions: butter / besself / cheby1 / maxflat Self-design: designfilt

26 Simplified Layout of Detection Circuit Pre-Amplification Filter (LPF / HPF / NOTCH / BPF) Post-Amplification Circuitry Voltage Level Shifter

27 This detection circuit could be the platform for building your term project

28 Goals Accuracy MOST IMPORTANT! Regardless of the complexity of the detection circuit Compare the detected signal with the results from exp.1 ECG: PR interval / QRS interval / ST intervals etc. EMG: Tonus measurement etc. 與實驗二結果比較量到的電信號波形穩定與否 Noise 的情況又是如何?SNR? 商用儀器 v.s. 自行設計之電路

29 Goals 1. ECG EMG 必須透過電路設計出適當的濾波器 2. EEG 可以藉由電腦設計出適當的濾波器 α: 8 13Hz β: 13 40Hz θ: 4~7Hz δ: 0.5~4Hz

30 PART II: 資料擷取與 APP 設計 DAQ and APP for Bio-Signal Detection

31 Simplified Layout of Detection Circuit Signal Inputs (3 Leads) ~µv ~mv Pre-Amplification Filter (LPF / HPF / NOTCH / BPF) Display Post-Amplification ADC Circuitry Voltage Level Shifter Signal Output (0V 5V)

35 Analog Input 類比輸入 Analog Outputs 類比輸出 Func. Generator 函數產生器 Manual Control 手動控制 Var. Power Supply 可變電源 Fix Power Supply & Ground 固定電源 & 接地

36 NI ELVISmx Instrument Launcher 可變電源供應器 - 可變電源供應器 +

37 NI ELVISmx Instrument Launcher 啟動頻率波形振幅 Offset

38 NI ELVISmx Instrument Launcher 顯示頻道歸零刻度 Time Base 啟動固定波形紀錄

39 NI ELVISmx Instrument Launcher

40 PARTI: Introduction Analog signal Digital signal Digital filter Decrease the chance of signal distortion System integration Arduino Uno v3 (or any mcu eval. board) User interface & display recorded signal Bluetooth (BT) module HC-05 App Inventor 2 Android APP

41 Arduino Uno Microcontroller evaluation board ATmega328 microcontroller Clock: 16 MHz 14 Digital I/O 6 Analog inputs 10 bits ADC Software serial function

42 Arduino IDE 1. Import Library 2. Define Variables/Constants 1. Setup Pins 2. Initialize Functions Do until power is turned off! 1. Read ADC output 2. Send ADC result via BT module

43 Arduino IDE Tool Please select the correct board and port

44 HC-05 Bluetooth Module Enter AT Mode 1. KEY: HIGH (or) 2. Push Button Down Before power up Bluetooth Module 1. AT 2. AT+NAME? 3. AT+PSWD? 4. AT+UART = Baud Rate, 停止位元, 同位 (parity) 位元

45 App Inventor 2 You need to have a Google Account URL: ai2.appinventor.mit.edu

46 App Inventor 2

47 App Inventor 2

48 App Inventor 2

49 Important! Arduino CANNOT sample negative voltages. Voltage range: Vref_- (i.e., GND) and Vref_+ (i.e., +5V, +3.3V or external voltage) What is your sampling frequency, and how is this defined in Arduino s code. Syntax: references Arduino App Inventor 2 Please download: Arduino software:

50 Demo Date: 23 October 2018 (12:20 14:00) Circuit: ECG(30%), EMG(30%) and EEG (20%) Display your recorded waveform on oscilloscope (ELVIS II) Display your recorded waveform on your designed APP (Arduino + App, 20%) Grading Accuracy of the bio-signal recorded App v.s. Oscilloscope

51 Report Date: 30 October 2018, 11am Contents Normal report format: Introduction, Method, Results, Discussions, Conclusions Design/Specification: circuits, Arduino program, App Additional questions! ( 詳見生醫工程網頁 )

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