SlideShare a Scribd company logo
1 of 3
Download to read offline
Tech Support: services@elecfreaks.com
Ultrasonic Ranging Module HC - SR04
Product features:
Ultrasonic ranging module HC - SR04 provides 2cm - 400cm non-contact
measurement function, the ranging accuracy can reach to 3mm. The modules
includes ultrasonic transmitters, receiver and control circuit. The basic principle
of work:
(1) Using IO trigger for at least 10us high level signal,
(2) The Module automatically sends eight 40 kHz and detect whether there is a
pulse signal back.
(3) IF the signal back, through high level , time of high output IO duration is
the time from sending ultrasonic to returning.
Test distance = (high level time×velocity of sound (340M/S) / 2,
Wire connecting direct as following:
5V Supply
Trigger Pulse Input
Echo Pulse Output
0V Ground
Electric Parameter
Working Voltage DC 5 V
Working Current 15mA
Working Frequency 40Hz
Max Range 4m
Min Range 2cm
MeasuringAngle 15 degree
Trigger Input Signal 10uS TTL pulse
Echo Output Signal Input TTL lever signal and the range in
proportion
Dimension 45*20*15mm
Vcc Trig Echo GND
Timing diagram
The Timing diagram is shown below. You only need to supply a short 10uS
pulse to the trigger input to start the ranging, and then the module will send out
an 8 cycle burst of ultrasound at 40 kHz and raise its echo. The Echo is a
distance object that is pulse width and the range in proportion .You can
calculate the range through the time interval between sending trigger signal and
receiving echo signal. Formula: uS / 58 = centimeters or uS / 148 =inch; or: the
range = high level time * velocity (340M/S) / 2; we suggest to use over 60ms
measurement cycle, in order to prevent trigger signal to the echo signal.
Attention:
The module is not suggested to connect directly to electric, if connected
electric, the GND terminal should be connected the module first, otherwise,
it will affect the normal work of the module.
When tested objects, the range of area is n ot less than 0.5 square meters
and the plane requests as smooth as possible, otherwise ,it will affect the
results of measuring.
www.Elecfreaks.com

More Related Content

What's hot

Why antenna radiates-explained
Why antenna radiates-explainedWhy antenna radiates-explained
Why antenna radiates-explainedVinoth Kumar K
 
Electro smog meters
Electro smog metersElectro smog meters
Electro smog meterslink2013
 
Introduction to vibration monitoring
Introduction to vibration monitoringIntroduction to vibration monitoring
Introduction to vibration monitoringKevin Pereira
 
Radar System with Arduino Processor
Radar System with Arduino ProcessorRadar System with Arduino Processor
Radar System with Arduino ProcessorMelek Sönmez
 
Interfacing ultrasonic rangefinder with avr mc us
Interfacing ultrasonic rangefinder with avr mc usInterfacing ultrasonic rangefinder with avr mc us
Interfacing ultrasonic rangefinder with avr mc usKushagra Ganeriwal
 
Fundamentals of vibration_measurement_and_analysis_explained
Fundamentals of vibration_measurement_and_analysis_explainedFundamentals of vibration_measurement_and_analysis_explained
Fundamentals of vibration_measurement_and_analysis_explainedvibratiob
 
Vibration measurement
Vibration measurement Vibration measurement
Vibration measurement rintusasmal
 
NF Digital Lock-in Amplifier LI5600 Series
NF Digital Lock-in Amplifier LI5600 SeriesNF Digital Lock-in Amplifier LI5600 Series
NF Digital Lock-in Amplifier LI5600 SeriesNIHON DENKEI SINGAPORE
 
Gunnebo Gate Management System
Gunnebo Gate Management SystemGunnebo Gate Management System
Gunnebo Gate Management SystemFalah Ahmad Sabri
 
How to identify and solve the problem that piezoelectric products unable to a...
How to identify and solve the problem that piezoelectric products unable to a...How to identify and solve the problem that piezoelectric products unable to a...
How to identify and solve the problem that piezoelectric products unable to a...wangwang49
 
Personal radar ppt 1
Personal radar ppt 1Personal radar ppt 1
Personal radar ppt 1Ronak Vyas
 

What's hot (19)

Radar
RadarRadar
Radar
 
Six channel fire monitoring & control
Six channel fire monitoring & controlSix channel fire monitoring & control
Six channel fire monitoring & control
 
Why antenna radiates-explained
Why antenna radiates-explainedWhy antenna radiates-explained
Why antenna radiates-explained
 
Electro smog meters
Electro smog metersElectro smog meters
Electro smog meters
 
Ultrasonic
UltrasonicUltrasonic
Ultrasonic
 
Introduction to vibration monitoring
Introduction to vibration monitoringIntroduction to vibration monitoring
Introduction to vibration monitoring
 
Sensors
SensorsSensors
Sensors
 
Radar System with Arduino Processor
Radar System with Arduino ProcessorRadar System with Arduino Processor
Radar System with Arduino Processor
 
Reverse car-parking
Reverse car-parkingReverse car-parking
Reverse car-parking
 
Wireless sensors
Wireless sensorsWireless sensors
Wireless sensors
 
Interfacing ultrasonic rangefinder with avr mc us
Interfacing ultrasonic rangefinder with avr mc usInterfacing ultrasonic rangefinder with avr mc us
Interfacing ultrasonic rangefinder with avr mc us
 
Fundamentals of vibration_measurement_and_analysis_explained
Fundamentals of vibration_measurement_and_analysis_explainedFundamentals of vibration_measurement_and_analysis_explained
Fundamentals of vibration_measurement_and_analysis_explained
 
Orhun Gural_Sensata
Orhun Gural_SensataOrhun Gural_Sensata
Orhun Gural_Sensata
 
Vibration measurement
Vibration measurement Vibration measurement
Vibration measurement
 
Contactless tachometer
Contactless tachometerContactless tachometer
Contactless tachometer
 
NF Digital Lock-in Amplifier LI5600 Series
NF Digital Lock-in Amplifier LI5600 SeriesNF Digital Lock-in Amplifier LI5600 Series
NF Digital Lock-in Amplifier LI5600 Series
 
Gunnebo Gate Management System
Gunnebo Gate Management SystemGunnebo Gate Management System
Gunnebo Gate Management System
 
How to identify and solve the problem that piezoelectric products unable to a...
How to identify and solve the problem that piezoelectric products unable to a...How to identify and solve the problem that piezoelectric products unable to a...
How to identify and solve the problem that piezoelectric products unable to a...
 
Personal radar ppt 1
Personal radar ppt 1Personal radar ppt 1
Personal radar ppt 1
 

Similar to Hcsr04

ULTRASONIC SENSOR.pdf
ULTRASONIC SENSOR.pdfULTRASONIC SENSOR.pdf
ULTRASONIC SENSOR.pdfJERANRAI1
 
Short Range Radar System using Arduino Uno
Short Range Radar System using Arduino UnoShort Range Radar System using Arduino Uno
Short Range Radar System using Arduino UnoIRJET Journal
 
Ultrsonic sensor_Arduino_DRKG.pptx
Ultrsonic sensor_Arduino_DRKG.pptxUltrsonic sensor_Arduino_DRKG.pptx
Ultrsonic sensor_Arduino_DRKG.pptxKesavanGopal1
 
IRJET- Distance Measurement with the Help of Ultrasonic Sensor
IRJET-  	  Distance Measurement with the Help of Ultrasonic SensorIRJET-  	  Distance Measurement with the Help of Ultrasonic Sensor
IRJET- Distance Measurement with the Help of Ultrasonic SensorIRJET Journal
 
Security System Based on Ultrasonic Sensor Technology
Security System Based on Ultrasonic Sensor TechnologySecurity System Based on Ultrasonic Sensor Technology
Security System Based on Ultrasonic Sensor TechnologyIOSR Journals
 
Ultrasonic level meter
Ultrasonic level meterUltrasonic level meter
Ultrasonic level meterhandson28
 
SENSORS AND BLUETOOTH COMMUNICATION
SENSORS AND BLUETOOTH COMMUNICATIONSENSORS AND BLUETOOTH COMMUNICATION
SENSORS AND BLUETOOTH COMMUNICATIONsoma saikiran
 
Close Loop V/F Control of Voltage Source Inverter using Sinusoidal PWM, Third...
Close Loop V/F Control of Voltage Source Inverter using Sinusoidal PWM, Third...Close Loop V/F Control of Voltage Source Inverter using Sinusoidal PWM, Third...
Close Loop V/F Control of Voltage Source Inverter using Sinusoidal PWM, Third...IAES-IJPEDS
 
Ultrasonic sensors
Ultrasonic sensorsUltrasonic sensors
Ultrasonic sensorsAnCh24
 
Hc sr04 users-manual
Hc sr04 users-manualHc sr04 users-manual
Hc sr04 users-manualnguyen nam
 
Sensor Based Blind Stick
Sensor Based Blind StickSensor Based Blind Stick
Sensor Based Blind StickGagandeep Singh
 
Ultrasonic waves experiment system
Ultrasonic waves experiment systemUltrasonic waves experiment system
Ultrasonic waves experiment systemMidoOoz
 
Oscilloscope Fundamentals, Hands-On Course at EELive 2014
Oscilloscope Fundamentals, Hands-On Course at EELive 2014Oscilloscope Fundamentals, Hands-On Course at EELive 2014
Oscilloscope Fundamentals, Hands-On Course at EELive 2014Rohde & Schwarz North America
 

Similar to Hcsr04 (20)

ULTRASONIC SENSOR.pdf
ULTRASONIC SENSOR.pdfULTRASONIC SENSOR.pdf
ULTRASONIC SENSOR.pdf
 
Ultrasonic sensor
Ultrasonic sensorUltrasonic sensor
Ultrasonic sensor
 
ultrasonic sensor.pptx
ultrasonic sensor.pptxultrasonic sensor.pptx
ultrasonic sensor.pptx
 
Ultrasonic_Based_Security_System
Ultrasonic_Based_Security_SystemUltrasonic_Based_Security_System
Ultrasonic_Based_Security_System
 
Short Range Radar System using Arduino Uno
Short Range Radar System using Arduino UnoShort Range Radar System using Arduino Uno
Short Range Radar System using Arduino Uno
 
Ultrsonic sensor_Arduino_DRKG.pptx
Ultrsonic sensor_Arduino_DRKG.pptxUltrsonic sensor_Arduino_DRKG.pptx
Ultrsonic sensor_Arduino_DRKG.pptx
 
IRJET- Distance Measurement with the Help of Ultrasonic Sensor
IRJET-  	  Distance Measurement with the Help of Ultrasonic SensorIRJET-  	  Distance Measurement with the Help of Ultrasonic Sensor
IRJET- Distance Measurement with the Help of Ultrasonic Sensor
 
Security System Based on Ultrasonic Sensor Technology
Security System Based on Ultrasonic Sensor TechnologySecurity System Based on Ultrasonic Sensor Technology
Security System Based on Ultrasonic Sensor Technology
 
Ultrasonic Level Transmitter
Ultrasonic Level TransmitterUltrasonic Level Transmitter
Ultrasonic Level Transmitter
 
ULTRASONIC PERIPATETIC SCANNER FOR AUTONOMOUS TEST BENCH USING RASPBERRY Pi
ULTRASONIC PERIPATETIC SCANNER FOR AUTONOMOUS TEST BENCH USING RASPBERRY PiULTRASONIC PERIPATETIC SCANNER FOR AUTONOMOUS TEST BENCH USING RASPBERRY Pi
ULTRASONIC PERIPATETIC SCANNER FOR AUTONOMOUS TEST BENCH USING RASPBERRY Pi
 
Ultrasonic level meter
Ultrasonic level meterUltrasonic level meter
Ultrasonic level meter
 
SENSORS AND BLUETOOTH COMMUNICATION
SENSORS AND BLUETOOTH COMMUNICATIONSENSORS AND BLUETOOTH COMMUNICATION
SENSORS AND BLUETOOTH COMMUNICATION
 
Close Loop V/F Control of Voltage Source Inverter using Sinusoidal PWM, Third...
Close Loop V/F Control of Voltage Source Inverter using Sinusoidal PWM, Third...Close Loop V/F Control of Voltage Source Inverter using Sinusoidal PWM, Third...
Close Loop V/F Control of Voltage Source Inverter using Sinusoidal PWM, Third...
 
Ultrasonic sensors
Ultrasonic sensorsUltrasonic sensors
Ultrasonic sensors
 
Hc sr04 users-manual
Hc sr04 users-manualHc sr04 users-manual
Hc sr04 users-manual
 
Sensor Based Blind Stick
Sensor Based Blind StickSensor Based Blind Stick
Sensor Based Blind Stick
 
Ultrasonic waves experiment system
Ultrasonic waves experiment systemUltrasonic waves experiment system
Ultrasonic waves experiment system
 
High frequency radar level meter zero902
High frequency radar  level meter zero902High frequency radar  level meter zero902
High frequency radar level meter zero902
 
Oscilloscope Fundamentals, Hands-On Course at EELive 2014
Oscilloscope Fundamentals, Hands-On Course at EELive 2014Oscilloscope Fundamentals, Hands-On Course at EELive 2014
Oscilloscope Fundamentals, Hands-On Course at EELive 2014
 
Acs712
Acs712Acs712
Acs712
 

Recently uploaded

Ecological Succession. ( ECOSYSTEM, B. Pharmacy, 1st Year, Sem-II, Environmen...
Ecological Succession. ( ECOSYSTEM, B. Pharmacy, 1st Year, Sem-II, Environmen...Ecological Succession. ( ECOSYSTEM, B. Pharmacy, 1st Year, Sem-II, Environmen...
Ecological Succession. ( ECOSYSTEM, B. Pharmacy, 1st Year, Sem-II, Environmen...Shubhangi Sonawane
 
How to Give a Domain for a Field in Odoo 17
How to Give a Domain for a Field in Odoo 17How to Give a Domain for a Field in Odoo 17
How to Give a Domain for a Field in Odoo 17Celine George
 
Unit-IV; Professional Sales Representative (PSR).pptx
Unit-IV; Professional Sales Representative (PSR).pptxUnit-IV; Professional Sales Representative (PSR).pptx
Unit-IV; Professional Sales Representative (PSR).pptxVishalSingh1417
 
Mixin Classes in Odoo 17 How to Extend Models Using Mixin Classes
Mixin Classes in Odoo 17  How to Extend Models Using Mixin ClassesMixin Classes in Odoo 17  How to Extend Models Using Mixin Classes
Mixin Classes in Odoo 17 How to Extend Models Using Mixin ClassesCeline George
 
Z Score,T Score, Percential Rank and Box Plot Graph
Z Score,T Score, Percential Rank and Box Plot GraphZ Score,T Score, Percential Rank and Box Plot Graph
Z Score,T Score, Percential Rank and Box Plot GraphThiyagu K
 
Web & Social Media Analytics Previous Year Question Paper.pdf
Web & Social Media Analytics Previous Year Question Paper.pdfWeb & Social Media Analytics Previous Year Question Paper.pdf
Web & Social Media Analytics Previous Year Question Paper.pdfJayanti Pande
 
Unit-V; Pricing (Pharma Marketing Management).pptx
Unit-V; Pricing (Pharma Marketing Management).pptxUnit-V; Pricing (Pharma Marketing Management).pptx
Unit-V; Pricing (Pharma Marketing Management).pptxVishalSingh1417
 
Gardella_PRCampaignConclusion Pitch Letter
Gardella_PRCampaignConclusion Pitch LetterGardella_PRCampaignConclusion Pitch Letter
Gardella_PRCampaignConclusion Pitch LetterMateoGardella
 
An Overview of Mutual Funds Bcom Project.pdf
An Overview of Mutual Funds Bcom Project.pdfAn Overview of Mutual Funds Bcom Project.pdf
An Overview of Mutual Funds Bcom Project.pdfSanaAli374401
 
Gardella_Mateo_IntellectualProperty.pdf.
Gardella_Mateo_IntellectualProperty.pdf.Gardella_Mateo_IntellectualProperty.pdf.
Gardella_Mateo_IntellectualProperty.pdf.MateoGardella
 
Class 11th Physics NEET formula sheet pdf
Class 11th Physics NEET formula sheet pdfClass 11th Physics NEET formula sheet pdf
Class 11th Physics NEET formula sheet pdfAyushMahapatra5
 
Beyond the EU: DORA and NIS 2 Directive's Global Impact
Beyond the EU: DORA and NIS 2 Directive's Global ImpactBeyond the EU: DORA and NIS 2 Directive's Global Impact
Beyond the EU: DORA and NIS 2 Directive's Global ImpactPECB
 
Nutritional Needs Presentation - HLTH 104
Nutritional Needs Presentation - HLTH 104Nutritional Needs Presentation - HLTH 104
Nutritional Needs Presentation - HLTH 104misteraugie
 
PROCESS RECORDING FORMAT.docx
PROCESS      RECORDING        FORMAT.docxPROCESS      RECORDING        FORMAT.docx
PROCESS RECORDING FORMAT.docxPoojaSen20
 
SOCIAL AND HISTORICAL CONTEXT - LFTVD.pptx
SOCIAL AND HISTORICAL CONTEXT - LFTVD.pptxSOCIAL AND HISTORICAL CONTEXT - LFTVD.pptx
SOCIAL AND HISTORICAL CONTEXT - LFTVD.pptxiammrhaywood
 
Measures of Dispersion and Variability: Range, QD, AD and SD
Measures of Dispersion and Variability: Range, QD, AD and SDMeasures of Dispersion and Variability: Range, QD, AD and SD
Measures of Dispersion and Variability: Range, QD, AD and SDThiyagu K
 
1029 - Danh muc Sach Giao Khoa 10 . pdf
1029 -  Danh muc Sach Giao Khoa 10 . pdf1029 -  Danh muc Sach Giao Khoa 10 . pdf
1029 - Danh muc Sach Giao Khoa 10 . pdfQucHHunhnh
 
microwave assisted reaction. General introduction
microwave assisted reaction. General introductionmicrowave assisted reaction. General introduction
microwave assisted reaction. General introductionMaksud Ahmed
 

Recently uploaded (20)

Ecological Succession. ( ECOSYSTEM, B. Pharmacy, 1st Year, Sem-II, Environmen...
Ecological Succession. ( ECOSYSTEM, B. Pharmacy, 1st Year, Sem-II, Environmen...Ecological Succession. ( ECOSYSTEM, B. Pharmacy, 1st Year, Sem-II, Environmen...
Ecological Succession. ( ECOSYSTEM, B. Pharmacy, 1st Year, Sem-II, Environmen...
 
How to Give a Domain for a Field in Odoo 17
How to Give a Domain for a Field in Odoo 17How to Give a Domain for a Field in Odoo 17
How to Give a Domain for a Field in Odoo 17
 
Unit-IV; Professional Sales Representative (PSR).pptx
Unit-IV; Professional Sales Representative (PSR).pptxUnit-IV; Professional Sales Representative (PSR).pptx
Unit-IV; Professional Sales Representative (PSR).pptx
 
Mixin Classes in Odoo 17 How to Extend Models Using Mixin Classes
Mixin Classes in Odoo 17  How to Extend Models Using Mixin ClassesMixin Classes in Odoo 17  How to Extend Models Using Mixin Classes
Mixin Classes in Odoo 17 How to Extend Models Using Mixin Classes
 
Z Score,T Score, Percential Rank and Box Plot Graph
Z Score,T Score, Percential Rank and Box Plot GraphZ Score,T Score, Percential Rank and Box Plot Graph
Z Score,T Score, Percential Rank and Box Plot Graph
 
INDIA QUIZ 2024 RLAC DELHI UNIVERSITY.pptx
INDIA QUIZ 2024 RLAC DELHI UNIVERSITY.pptxINDIA QUIZ 2024 RLAC DELHI UNIVERSITY.pptx
INDIA QUIZ 2024 RLAC DELHI UNIVERSITY.pptx
 
Web & Social Media Analytics Previous Year Question Paper.pdf
Web & Social Media Analytics Previous Year Question Paper.pdfWeb & Social Media Analytics Previous Year Question Paper.pdf
Web & Social Media Analytics Previous Year Question Paper.pdf
 
Unit-V; Pricing (Pharma Marketing Management).pptx
Unit-V; Pricing (Pharma Marketing Management).pptxUnit-V; Pricing (Pharma Marketing Management).pptx
Unit-V; Pricing (Pharma Marketing Management).pptx
 
Gardella_PRCampaignConclusion Pitch Letter
Gardella_PRCampaignConclusion Pitch LetterGardella_PRCampaignConclusion Pitch Letter
Gardella_PRCampaignConclusion Pitch Letter
 
An Overview of Mutual Funds Bcom Project.pdf
An Overview of Mutual Funds Bcom Project.pdfAn Overview of Mutual Funds Bcom Project.pdf
An Overview of Mutual Funds Bcom Project.pdf
 
Gardella_Mateo_IntellectualProperty.pdf.
Gardella_Mateo_IntellectualProperty.pdf.Gardella_Mateo_IntellectualProperty.pdf.
Gardella_Mateo_IntellectualProperty.pdf.
 
Class 11th Physics NEET formula sheet pdf
Class 11th Physics NEET formula sheet pdfClass 11th Physics NEET formula sheet pdf
Class 11th Physics NEET formula sheet pdf
 
Beyond the EU: DORA and NIS 2 Directive's Global Impact
Beyond the EU: DORA and NIS 2 Directive's Global ImpactBeyond the EU: DORA and NIS 2 Directive's Global Impact
Beyond the EU: DORA and NIS 2 Directive's Global Impact
 
Nutritional Needs Presentation - HLTH 104
Nutritional Needs Presentation - HLTH 104Nutritional Needs Presentation - HLTH 104
Nutritional Needs Presentation - HLTH 104
 
Mehran University Newsletter Vol-X, Issue-I, 2024
Mehran University Newsletter Vol-X, Issue-I, 2024Mehran University Newsletter Vol-X, Issue-I, 2024
Mehran University Newsletter Vol-X, Issue-I, 2024
 
PROCESS RECORDING FORMAT.docx
PROCESS      RECORDING        FORMAT.docxPROCESS      RECORDING        FORMAT.docx
PROCESS RECORDING FORMAT.docx
 
SOCIAL AND HISTORICAL CONTEXT - LFTVD.pptx
SOCIAL AND HISTORICAL CONTEXT - LFTVD.pptxSOCIAL AND HISTORICAL CONTEXT - LFTVD.pptx
SOCIAL AND HISTORICAL CONTEXT - LFTVD.pptx
 
Measures of Dispersion and Variability: Range, QD, AD and SD
Measures of Dispersion and Variability: Range, QD, AD and SDMeasures of Dispersion and Variability: Range, QD, AD and SD
Measures of Dispersion and Variability: Range, QD, AD and SD
 
1029 - Danh muc Sach Giao Khoa 10 . pdf
1029 -  Danh muc Sach Giao Khoa 10 . pdf1029 -  Danh muc Sach Giao Khoa 10 . pdf
1029 - Danh muc Sach Giao Khoa 10 . pdf
 
microwave assisted reaction. General introduction
microwave assisted reaction. General introductionmicrowave assisted reaction. General introduction
microwave assisted reaction. General introduction
 

Hcsr04

  • 1. Tech Support: services@elecfreaks.com Ultrasonic Ranging Module HC - SR04 Product features: Ultrasonic ranging module HC - SR04 provides 2cm - 400cm non-contact measurement function, the ranging accuracy can reach to 3mm. The modules includes ultrasonic transmitters, receiver and control circuit. The basic principle of work: (1) Using IO trigger for at least 10us high level signal, (2) The Module automatically sends eight 40 kHz and detect whether there is a pulse signal back. (3) IF the signal back, through high level , time of high output IO duration is the time from sending ultrasonic to returning. Test distance = (high level time×velocity of sound (340M/S) / 2, Wire connecting direct as following: 5V Supply Trigger Pulse Input Echo Pulse Output 0V Ground Electric Parameter Working Voltage DC 5 V Working Current 15mA Working Frequency 40Hz Max Range 4m Min Range 2cm MeasuringAngle 15 degree Trigger Input Signal 10uS TTL pulse Echo Output Signal Input TTL lever signal and the range in proportion Dimension 45*20*15mm
  • 2. Vcc Trig Echo GND Timing diagram The Timing diagram is shown below. You only need to supply a short 10uS pulse to the trigger input to start the ranging, and then the module will send out an 8 cycle burst of ultrasound at 40 kHz and raise its echo. The Echo is a distance object that is pulse width and the range in proportion .You can calculate the range through the time interval between sending trigger signal and receiving echo signal. Formula: uS / 58 = centimeters or uS / 148 =inch; or: the range = high level time * velocity (340M/S) / 2; we suggest to use over 60ms measurement cycle, in order to prevent trigger signal to the echo signal.
  • 3. Attention: The module is not suggested to connect directly to electric, if connected electric, the GND terminal should be connected the module first, otherwise, it will affect the normal work of the module. When tested objects, the range of area is n ot less than 0.5 square meters and the plane requests as smooth as possible, otherwise ,it will affect the results of measuring. www.Elecfreaks.com