Shimmer Shimmer3 Bedienungsanleitung

Realtime Technologies Ltd IMU User Manual

EMG User Guide

Revision 1.12

Realtime Technologies Ltd EMG User Guide

Legal Notices and Disclaimer

Redistribution IS permitted provided that the following conditions are met:

Redistributions must retain the copyright notice, and the following disclaimer. Redistributions in electronic form must reproduce the above

copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the

document.

Neither the name of Shimmer Research, or Realtime Technologies Ltd. nor the names of its contributors may be used to endorse or promote

products derived from this document without specific prior written permission.

THIS DOCUMENT IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,

INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE

DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR

SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,

WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

OF THIS DOCUMENT, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Realtime Technologies Ltd EMG User Guide

Table of Contents

1. Introduction.............................................................................................................................. 5

2. General Information ................................................................................................................. 6

2.1. Safety Information ............................................................................................................. 6

2.2. Pre-Requisites.................................................................................................................... 6

2.3. EMG Unit Specification Overview....................................................................................... 6

3. Using the EMG Unit................................................................................................................... 7

3.1. Basic System Overview....................................................................................................... 7

Common Mode Rejection .......................................................................................................... 8

3.2. EMG Electrode Positioning................................................................................................. 8

3.3. Configuration Options and Recommended Settings............................................................ 9

Data Rate................................................................................................................................. 10

Gain......................................................................................................................................... 10

Input Multiplexer..................................................................................................................... 11

Right-Leg Drive (Common-mode Rejection) ............................................................................. 11

Test Signal ............................................................................................................................... 12

4. Measuring EMG Signals........................................................................................................... 13

4.1. Best Practice on How to Acquire an EMG signal................................................................ 13

Skin Preparation ...................................................................................................................... 13

Research.................................................................................................................................. 13

Sampling Frequency................................................................................................................. 13

4.2. Signal Calibration ............................................................................................................. 13

ADC Offset Measurement........................................................................................................ 14

Gain Measurement.................................................................................................................. 14

5. Common EMG Signal Processing Techniques .......................................................................... 15

5.1. Filtering [2] ...................................................................................................................... 15

5.2. Extracting the Linear Envelope of an EMG Signal [3]......................................................... 16

5.3. Integration Techniques [3] ............................................................................................... 17

5.4. Normalisation [3, 4] ......................................................................................................... 18

5.5. Frequency Domain Analysis [3, 5]..................................................................................... 18

6. Hardware Considerations........................................................................................................ 19

Realtime Technologies Ltd EMG User Guide

6.1. Board Layout.................................................................................................................... 19

6.2. Channel assignment......................................................................................................... 20

6.3. Data considerations ......................................................................................................... 21

7. Firmware Considerations ........................................................................................................ 21

8. Troubleshooting...................................................................................................................... 21

8.1. Verifying That Your EMG Unit Works................................................................................ 21

8.2. Signal Quality ................................................................................................................... 21

9. References .............................................................................................................................. 22

10. Appendices.......................................................................................................................... 23

10.1. Legacy Hardware.......................................................................................................... 23

Board Layout ........................................................................................................................... 23

Channel assignment................................................................................................................. 24

Troubleshooting ...................................................................................................................... 25

10.2. Opening the Shimmer3 expansion enclosure................................................................ 25

Realtime Technologies Ltd EMG User Guide

1. Introduction

This document is an accompaniment to the Shimmer3 EMG Unit (called EMG Unit in the rest of this

document). Its purpose is to aid the user in getting started with EMG measurements.

The EMG Unit can be configured to measure electrical signals from the skin, including EMG

(Electromyograph). Any user who wishes to use Shimmer hardware to record ECG

(Electrocardiograph) signals from the skin should refer to the Shimmer3 ECG User Guide, which is

available for download from http://www.shimmersensing.com.

The five-wire EMG Unit can be configured to record the electrical activity associated with skeletal

muscle contractions; this can be used to analyze and measure the biomechanics of human or animal

movement. The EMG Unit is non-invasive, measuring surface EMG and, therefore, the activity it

measures is a representation of the activity of the whole muscle or group of muscles whose

electrical activity is detectable at the electrode site. The EMG Unit offers a wireless solution for a

host of muscle, gait and posture disturbances in an easy to integrate and ergonomically valuable

arrangement. Signals are collected from the skin via five wires, which are connected externally to

the Shimmer3 EMG Unit, and to which should be attached conventional disposable electrodes. The

EMG Unit uses a low-power, multichannel analog front-end especially designed for biopotential

measurements, consisting of delta-sigma analog-to-digital converters and programmable gain

amplifiers.

Realtime Technologies Ltd EMG User Guide

2. General Information

2.1. Safety Information

As a precaution it is important to note that the EMG leads are not to be applied to the subject's body

while unit is in a USB dock or multi-charger.

2.2. Pre-Requisites

A Shimmer3 EMG Unit programmed with appropriate firmware. For example, LogAndStream

(v0.6.0 or greater) can be used to stream data over Bluetooth and/or log data to the SD card

or SDLog (v0.12.0 or greater) can be used to log data to the SD card; both are available for

download from www.shimmersensing.com.

Five DIN snap leads.

-9-inch and 18-inch leads are shipped with the EMG Development Kit and EMG

Bundles.

-Replacements can be purchased from www.shimmersensing.com.

Surface EMG electrodes.

-Disposable electrodes are shipped with the EMG Development Kit and EMG Bundles.

-For replacements, see www.shimmersensing.com. Alternatively, the Covidien

Kendall Disposable Surface EMG/ECG/EKG electrodes 1" (24mm) or Covidien Kendall

Disposable Surface EMG/ECG/EKG electrodes 1 3/8" (35mm), available on www.bio-

medical.com with product codes 'BRD H124SG' and 'BRD H135SG', respectively, and

the Ambu Blue Sensor T electrodes, available from various suppliers, are all suitable

options and have been validated for use with Shimmer equipment.

2.3. EMG Unit Specification Overview

For specifications on the general Shimmer3 part, (i.e. microprocessor, radio, data storage

and inertial sensors) of the Shimmer3 EMG Unit, please refer to the Shimmer User Manual.

Gain: Configurable (1, 2, 3, 4, 6, 8, 12).

Data rate: software configurable (125, 250, 500, 1000, 2000, 4000, 8000 SPS).Input

differential dynamic range

: approx 800 mV (for gain = 6).

Bandwidth

: 8.4 kHz

Ground: Wilson Type Driven Ground

Input Protection: ESD and RF/EMI filtering; Current limiting; inputs include defibrillation

protection (survive only, not repeat). NOTE: For inputs Ch1N and Ch1P the defibrillation

protection is not present to facilitate Respiration demodulation when the EMG Unit is

configured as ECG Unit, refer to Shimmer3 ECG Unit for details.

Connections: Input Ch1N, Input Ch1P, Input Ch2N, Input Ch2P, Reference (Ref).

oAll Hospital-Grade 1mm Touchproof IEC/EN 60601-1 DIN42-802 jacks.

Calculated specification; exact value subject to environmental and component variation. ADS1292R is

optimized for power with a differential input signal of approx. 300 mV when gain = 6.

Specifications from ADS1292R datasheet; exact value subject to environmental and component variation.

Realtime Technologies Ltd EMG User Guide

Ultra-lightweight (31 grams); Compact Dimensions (65 x 32 x 12 mm).

EEPROM memory: 2048 bytes.

3. Using the EMG Unit

3.1. Basic System Overview

Figure 3-1: Simplified Block Diagram

Electrodes: Each EMG board connects to Ch2N (white), Ch2P (black), Ref (green), Ch1N (red)

and Ch1P (brown) electrodes.

Defibrillation protection: Survive only; not repeat. No defibrillation protection is present for

inputs Ch2P and Ch2N to facilitate Respiration demodulation (refer to Shimmer3 ECG User

Guide).

EMI Filter: Reduces electromagnetic interference; -3dB filter bandwidth is approximately

3MHz.

Right-Leg Drive Amplifier (RLD Amp): Counteracts common-mode interference (e.g. from

mains power lines, fluorescent lights and other sources).

Programmable Gain Amplifier (PGA): Increases amplitude of input signal; seven gain

settings available. See Section 4.2 to accurately calculate the gain of your device. Default

gain is configurable in software.

 Analog to Digital Converters ( ADC): Converts the input analogue signals to a digital

representation of this signal by a 24-bit signed integer value to each sample. These values

are fed to the Shimmer3 processor to be saved to the SD card or transmitted over Bluetooth.

Realtime Technologies Ltd EMG User Guide

Common Mode Rejection

Each EMG board connects to five electrodes, namely, a positive and a negative electrode for each for

two channels and a neutral reference electrode. The reason for using three electrodes in this way is

that the EMG signal amplitude is, typically, very small relative to noise, for example, interference

from power lines and nearby electrical sources. The signal picked up by each individual electrode

consists of noise from the environment along with the local electrical signal from the muscles at the

position of skin contact. The noise from the environment is common to all electrodes, whilst the

local electrical signal depends on the electrode’s position. Thus, if one signal is subtracted from

another, the common component (the undesired noise) will be cancelled by the subtraction, whilst

the local signals (the desired EMG component) will remain after subtraction and can be amplified to

make it easier to process. This process is called Common Mode Rejection (CMR) and is used in the

Shimmer EMG board.

3.2. EMG Electrode Positioning

The inputs to the EMG Unit are labelled according to the suggested placement, in order to measure

EMG data from two channels:

Channel 1:

oCh1N Negative terminal

oCh1P Positive Terminal

Channel 2:

oCh2N Negative terminal

oCh2P Positive Terminal

Reference electrode:

oRef

Figure 3-2: Example positioning of the electrodes for EMG measurement.

Realtime Technologies Ltd EMG User Guide

Figure 3-2 shows an example of how the electrodes should be positioned on the body. The positive

and negative electrodes should be placed in parallel with the muscle fibres of the muscle being

measured, near the centre of the muscle. The reference electrode should be placed at an electrically

neutral point of the body, as far away as reasonably possible from the muscle being measured. Bony

prominences such as those at the ankle and the wrist are recommended.

The following recommendations should also be noted:

The electrode material should be Ag/AgCl and the ideal centre to centre inter-electrode

distance for the positive and negative electrodes is 20mm. The electrode size should not

exceed 10mm.

The electrodes must NOT be placed on the tendon of the muscle. As muscles reach their

tendon point the fibres become thinner and produce an EMG signal with decreased

amplitude.

The electrodes must NOT be placed on the motor point of the muscle. This gives inaccurate

data as the signal produced is a summation of both nervous and muscular activity and as

such does not just represent the activity of the muscle.

The electrodes must NOT be placed on the outside edges of the muscle. This increases the

chance of picking up crosstalk signals from other muscles which are not being measured.

3.3. Configuration Options and Recommended Settings

The EMG Unit contains two ADS1292R chips from Texas Instruments; these have a very wide and

varied range of available configuration options. These chips are referred to as "Chip1" and "Chip2"

throughout this document. This section aims to provide recommended settings, which will suit the

needs of most EMG measurement applications. The experienced user who wishes to have full

control over all of the configuration settings should refer to the ADS1292R datasheet from Texas

Instruments for more details.

There are two ADS1292R chips on the EMG Unit and each of these chips has eleven bytes of

configurable register settings. Ten of these configurable bytes are listed in Table 3-1 and their

recommended values are discussed in this section. The final byte, which pertains to GPIO settings, is

dealt with in firmware and not discussed here. Users should note that, for EMG measurement, only

one of the ADS1292R chips (referred to as "Chip1") should be active.

Byte

Name

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

CONFIG1:

Configuration Register 1

Data Rate

(DR2, DR1, DR0)

CONFIG2:

Configuration Register 2

X 3

INT_T

EST

TEST_F

REQ

LOFF:

Lead-Off Control Register

CH1SET:

Channel 1 Settings

Gain1

(G1_2, G1_1, G1_0)

MUX1

(M1_3, M1_2, M1_1, M1_0)

The Bit 3 in CONFIG2 denotes “X=0” for SR47-1 revision, and “X=1” for SR47-4 and greater revisions. This

feature has been configured automatically in both LogAndStream 0.11.0 and SDLog_v0.19.0 (and newer).

Realtime Technologies Ltd EMG User Guide

CH2SET:

Channel 2 Settings

Gain2

(G2_2, G2_1, G2_0)

MUX2

(M2_3, M2_2, M2_1, M2_0)

RLD_SENS:

Right Leg Drive Sense Selection

PDB_RL

RLD_LO

FF_SENS

RLD Settings

(RLD2N, RLD2P, RLD1N, RLD1P)

LOFF_SENS:

Lead-Off Sense Selection

LOFF_STAT:

Lead-Off Status Selection

RESP1:

Respiration Control Register 1

RESP2:

Respiration Control Register 2

RLDRE

F_INT

Table 3-1 ADS1292R configuration register bytes - recommended values

Table 3-1 lists the recommended values of the ADS1292R configuration register bytes. The values of

the individual bits are listed in the columns labelled Bit 7 (MSB), Bit 6, and so on to Bit 0 (LSB). The

recommended values of some sets of bits, like multiplexer (MUX) settings, channel gain settings and

others, differ depending on the type of signal being measured (e.g. ECG or EMG), and others, like

output data rate and test signal, depend on the user's preferences.

Data Rate

The Data Rate for each chip can be set by modifying the three LSBs of the CONFIG1 register (Byte 0).

Table 3-2 lists the valid options and their corresponding data rate value in units of samples per

second (SPS). For EMG, a data rate of 500 SPS or more is recommended, although the needs of a

given application may vary.

Data Rate (SPS)

DR2

DR1

DR0

125

250

500 (recommended)

1000

2000

4000

8000

DO NOT USE

Table 3-2 EMG Data Rate options

Gain

The Gain setting can be configured independently for each of the two data channels on each chip by

modifying bits 4 - 6 of the CH1SET byte for channel 1 and of the CH2SET byte for channel 2,

respectively. The gain bits for channel 1 of a given chip are listed as G1_2 (MSB), G1_1 and G1_0

(LSB) in Table 3-1, whilst the equivalent for channel2 of the chip are listed as G2_2, G2_1 and G2_0,

respectively. These are collectively referred to as Gx_2, Gx_1 and Gx_0, respectively, in Table 3-3,

which lists the valid options and the corresponding gain value for each. For EMG, a gain value of 12 is

recommended.

Gain

Gx_2

Gx_1

Gx_0

6 (default)

Andere Handbücher für Shimmer3

Inhaltsverzeichnis

Andere Shimmer Zubehör Handbücher

Shimmer

Shimmer 3 Bedienungsanleitung

Beliebte Zubehör Handbücher anderer Marken

Hillco

Hillco 2810 Bedienungsanleitung

Siemens

Siemens QSA2700D Bedienerhandbuch

Contours

Contours ZY024 Bedienungsanleitung

Saivod

Saivod VS621 Bedienungsanleitung

Virtuox

Virtuox VirtuCLEAN 2.0 Bedienungsanleitung

SCE

SCE ENVIRO-THERM SCE-TE170B24VSS Bedienungsanleitung

Z-Wave

Z-Wave HSD-200Z Bedienungsanleitung

turck

turck FMX-IM-2UPLI63FX Bedienungsanleitung

Decagon Devices

Decagon Devices 10HS Bedienungsanleitung

UPPAbaby

UPPAbaby Cup Holder Bedienungsanleitung

Elko

Elko SmartSensor Leakage Wireless Bedienungsanleitung

Grizzly

Grizzly H8371 Bedienungsanleitung

Panasonic

Panasonic HG-T Series Bedienungsanleitung

IFM Electronic

IFM Electronic Efector 250 Series Referenzhandbuch

DigiDesign

DigiDesign 888/24 I/O Bedienungsanleitung

PROZIS

PROZIS QUAY Bedienungsanleitung

patagonia

patagonia PSI Vest Bedienungsanleitung

SFC Energy

SFC Energy EFOY GO! Bedienungsanleitung