Motion sensor - Data Harvest
Contents
1. Motion sensor Product No 3270 Ranges e Walk 0 15 3m Resolution 0 001 m 1 mm e Distance 0 15 1m Resolution 0 001 m 1 mm e Distance 0 15 2m Resolution 0 001 m 1 mm e Distance 0 15 4m Resolution 0 001 m 1 mm e Distance 0 15 8m Resolution 0 001 m 1 mm e Distance 15 800 cm Resolution 0 1 cm e Distance 6 300 inches Resolution 0 1 inch RX e Time 1 000 50 000 us KY DATA HARVEST Resolution 1 us 40 0 0 XX OY M Data Harvest Group Ltd 1 Eden Court Leighton Buzzard Beds LU7 4FY Tel 01525 373666 Fax 01525 851638 e mail sales data harvest co uk www data harvest co uk DS 041 Data Harvest Freely photocopiable for use within the purchasers establishment Simart Motion sensor MIC OCUGCUOM a NETE E EE A TE EE E E EE TE EE A AE E 2 CONNEC CAG rinder e E E EEE E E E E E bsenetad xbemsee one 2 PRIS S EEE EE EPON PEE EE NEE A AAE E E E E A EE 3 PracicaliMNormaloN corset devneSes mnencscctanendastanctaeh tatenctenduesalee aa aSa a aeea a aaia 3 LUERE e EEA T PEE EE AEE EEIN E E E EE TE EEE T WI AO oaa E E E E E E E E E EER T To create Velocity or Acceleration Gata ccccccccceceeeseeeeeeeeeeseeeeeeeeeeeseeeeseeeeesusesseseessneeesanees 10 Creating Presets sts cis dass detccissade snitt scouted Saco dew needa lated delaa Sanacuis sxdaydeeivdup asians Sevoadddle dasadeoanweideewmadters 11 NANO oc soca Sa tne tec ical cee ie a E E EE E debate E E erie acceedee2. Select Post log Function from the Tools menu Select the Formula function ax bx c Next x the Distance data set Next Change the name to Displacement a 0 b 1 using 1 turns the data to positive values as the subtraction of c gives negative values e c enter the distance from the Motion sensor to the floor e Click on Finish Force sensor E 5 Spring gt BTE SS Mesh guard TTI iit it ANN Motion sensor Motion sensor 2 Simple harmonic motion energy changes extension characteristics oscillation of a spring The Force sensor is used to measure the force in the spring as it oscillates The position of the mass is monitored using the Motion sensor Simart Motion sensor Cart with reflector fitted Motion sensor attached to the Dynamics System track dA 3 Used to plot the position of the trolley on the slope to find how the distance and speed change as a cart rolls up and down a slope investigating whether acceleration depends on the angle of the slope measuring g by rolling a cart down a slope etc 4 Elastic and inelastic collisions using two Motion sensors and carts Smart Motion sensor The two Motion sensors need to be angled slightly away from the track about 12 so they do not interfere with each other 5 Detecting movement Measuring distance against time and using this information to calculate the veloci
3. 2 344 8 ms Echo time s 5800 x 10 The value of the woy of sound in air increases with temperature At 0 C v 331 3 ms If the velocity of sound increases at 0 607 ms C then at 24 C v 331 3 24 x 0 607 331 3 14 6 345 9 ms poe of oe n air 342 23 342 83 343 44 344 05 344 65 345 26 345 87 D of agi air 346 47 347 08 347 69 348 30 348 90 349 51 350 12 Investigations e Walking toward and away from the Sensor Movement of an object up or down a slope Simple harmonic motion Newton s laws of motion Pendulum motion Air track gliders collisions Acceleration due to gravity free fall pendulum swing objects dropped or tossed upward Balanced forces Conservation of energy a bouncing object Speed of sound Energy changes in simple harmonic motion Oscillation of a spring Can be used with a Force sensor to e Study the relationship between force amp motion e To study collision and impulse e Simple harmonic motion e Spring characteristics extension oscillation SHM Simart Examples 1 Measuring gravity by free fall Select an intersample time of 20 ms and start condition of distance rises above 30 cm Hold ball about 10 cm below the Motion sensor click on Start release the ball and move hands away quickly If the ball is dropped the distance data will be from the Motion sensor to the ball To alter data to show distance of the ball from the floor
4. The best size is 15 cm diameter or more Using a light ball e g an inflatable beach ball to measure gravity is not advised since the air resistance compared to gravitational force will be too large A basketball gives good results For most investigations logging using Graph mode with a sample rate of 20 ms gives the best results If data wavers try varying the sample rate In some circumstances the faster the samples rate the shorter the distance can be detected reliably Sometimes a reflected pulse can cause invalid readings that may disappear at other frequencies If using more than one Motion sensor at the same time ensure they are not close together as they will hear each others echo and cause false readings If using two on a track angle the sensors slightly away from the track about 12 so their ultrasound cones do not interfere see page 10 Smart smart Motion sensor Time range The Time range will measure the time taken for the pulse to travel to the object and then back again With this range the Motion sensor can be used to measure the speed of sound Place the Motion sensor at least one metre away from the object Select either Meter or Test Mode and record a value Example the Motion sensor was placed 1 metre away from a wall one metre to the wall and one metre back a distance of 2 metres The value for time measurement was 5800 us 5800 x10 s Speed of sound ms Distance for echo to travel m
5. Repeat in the second graph but deselect Distance e Right click in the graph area and select Predict Use the predict tool to draw a line in each graph for the pupils to follow Click with the right mouse button to finish the line 05 0 Time ss Set up file The set up for an experiment recording times interval between samples any start conditions or pre triggers plus options for display such as number of graphs predictions deselected channels pre log functions etc can be saved as a Setup file for future use e Select Save Setup from the File menu e Type ina suitable name for the experiment this is the name that will be displayed in the My Investigations list Click on OK e The Save Setup file dialogue box will open Alter the file name if required and Save to the currently logged on user s My Documents directory EasySense Files Setup Files SSS type file To open the setup file e From the Home screen select Open gt Setup Select the setup file from the My Investigation list Warranty All Data Harvest Sensors are warranted to be free from defects in materials and workmanship for a period of 12 months from the date of purchase provided they have been used in accordance with any instructions under normal laboratory conditions This warranty does not apply if the Sensor has been damaged by accident or misuse 12 Simart Motion sensor In the event of a fault developing within the 12 month period the S
6. able if the distance graph is differentiated e The Motion sensor will continue to send pulses until the EASYSENSE unit stops asking for a reading This may result in the clicking noise continuing after logging has stopped e lf your EASYSENSE unit goes into sleep mode nothing shown on LCD screen the red LED on the Motion sensor will turn off and it will stop sending a pulse until the logger wakes up to take a sample e Automatic correction for variation in air temperature has been incorporated into the Distance ranges The Motion sensor will use its internal temperature sensor to apply a correction factor to the value for speed of sound used in calculating the distance 344 ms at 21 C Without compensation values for large distances between hot and cold days could have an error of up to 0 5 m The Time range is not temperature compensated There is no compensation made for relative humidity or air pressure e Although the moulding of the Motion sensor has been designed to help protect the transducer extra protection will be required if an object is being dropped from above A protective wire mesh such as an office in tray could be used Test to ensure the wire does not interfere with the echo the cone of the echo is at its narrowest close to the transducer e Power requirements The Motion sensor takes the power it requires from the EASYSENSE unit If logging continuously for long periods connect the logger to a power s
7. dden a sesceaeaecaiees 12 Introduction The Smart Q Motion Sensor is a sonar device that emits ultrasonic pulses which reflect off an object It measures the time it takes a high frequency sound pulse to travel from the Sensor to an object and back This time data is used together with the speed of sound to determine the distance of an object from the Sensor The Motion sensor is supplied with a steel rod size 80 mm long x 10 mm diameter with a M6 thread The rod can be screwed into the mounting threads which are found at the base and on the sides of the Motion sensor The rod can be used for clamping into a suitable holding device e g aretort stand The Smart Q Motion Sensor is equipped with a micro controller that greatly improves the accuracy precision and consistency It is supplied calibrated and the stored calibration is automatically loaded when the Motion sensor is connected Connecting Mounting thread gt sg Oso lt Mounting thread Red signal received LED lt 4 Insert the sensor cable with the locating arrow facing forwards A Mounting thread e Push one end of the sensor cable supplied with the EASYSENSE unit into the shape socket on the side of the Motion sensor with the locating arrow on the cable facing forwards e Connect the other end of the cable to the input socket on the EASYSENSE unit e The EASYSENSE unit will detect that the Motion sensor is connected and display values using
8. e EasySense software 1 Select EasyLog from the Home screen D 2 Select the New recording wizard icon Mew Real Time Logging Wizard Click on the sensor s name it will be listed using its current range Sensor 2 4 A set sensor range window will open Select the Sensor 3 required range then OK Fy sensor 5 5 Select Finish to exit the wizard Or 1 From the Home screen select Sensor Config from the Settings menu 2 Select the Motion sensor from the list and click on the Change Range button 3 The current range will be highlighted Select the required range and click on OK 4 Close Sensor Config The range setting will be retained until changed by the user Practical information The Motion sensor emits pulses of ultrasonic sound waves from the gold plated foil of the transducer The Motion sensor then listens for the echo that results from an obstacle in the beams path The time difference between transmission of the signal and the corresponding echo together with speed in air is then used to determine the distance to the nearest object Any object that reflects sound can be used as a target Note The Motion Sensor will report the distance to the closest object that produces a sufficiently strong echo this can be any object such as chairs or tables that are found in the cone of the ultrasound e Fastest Speed The maximum sample rate of the Motion sensor is 50 per second 50 Hz 20 ms interval betwe
9. el Next Enter the units as appropriate e g Velocity m m s cm cm s in in s or Acceleration m m s s cm cm s s in in s s Finish Destance Veloe 1 024 2 529 9 716 Distance m Ball drop 2 000 5 A 1 800 Acceleration 1 600 1 400 4 1 200 y Distance 1 000 0 800 0 600 0 400 4 0 200 4 Velocity 0 000 Creating Presets Creating a Distance Preset From the Home screen select Graph On the first page of the logging wizard that opens click on the sensor name and select a suitable range e g Walk 3 m Select Next and then the time span e g 10 seconds 20 ms interval Select Next and enter a suitable trigger Finish Right click in the graph area and select Predict Use the predict tool to draw a line on the graph for the pupils to follow left click at start move the mouse and a thick black line will appear click with left hand mouse button at different points on the graph to fix the line in position right click to stop and deselect Predict Simart Motion sensor Creating a Distance and Velocity preset displayed on 2 graphs e Use a Pre log Function to create a Velocity preset function don t forget to alter the axis limits to a suitable minimum amp maximum value e From Options select Number of Graphs select 2 as the number e To display a different data set in each graph right click in the first graph area select Show or Hide Channels and deselect Velocity
10. en samples If an interval between samples of less than 20 milliseconds is selected the set up will be rejected or the values obtained will default to zero e The data from the Motion sensor is serial and is not suitable for use with Timing functions or Time amp Motion mode in the EasySense software or data loggers These functions will only use data from switch type digital sensors e The quality of the reflecting surface used as a target is critical The nature of sound wave reflection varies according to the texture and structure of a surface The best target is Simart Motion sensor an object that will reflect sound waves in a single outgoing direction with little absorbed shiny glossy or polished solid or hard objects The worst targets are those with sound energy absorbing surfaces Some modern building materials and finishes have been deliberately engineered to have sound absorbing properties e g fibreglass or acoustically absorptive surfaces like velour curtains acoustical ceiling tiles or sound absorptive panels If a reflection is diffusing rough materials matt paint plaster etc sound waves can tend to bounce off in many directions scatter energy rather than reflect it coherently Sound waves may not return with sufficient power to give a valid result Good reflectors Questionable or poor reflectors Glass or acrylic sheet Plaster board partitions Metal plate Suspended ceiling tiles Stiff card Plastic foam
11. ensor must be returned to Data Harvest for repair or replacement at no expense to the user other than postal charges Note Data Harvest products are designed for educational use and are not intended for use in industrial medical or commercial applications WEEE Waste Electrical and Electronic Equipment Legislation Data Harvest Group Lid is fully compliant with WEEE legislation and is pleased to provide a disposal service for any of our products when their life expires Simply return them to us clearly identified as life expired and we will dispose of them for you 13
12. ong enough reflection e g by wearing soft sound absorbing jumper Remove the jumper or get the person to hold an object e g a book or basketball flat against them to act as the reflector Avoid large targets that may flap about e When you are setting up an investigation imagine the ultrasound beam extending out in a cone shape Check for stationary objects e g tables chairs walls and floors that could be positioned in that cone they maybe detected instead of the target 5 Motion sensor Motion ir Motion sensor HNM PHAN The work surface Nothing is is being detected interfering before the target with the signal so data will be so data will be inaccurate correct The work surface is being detected before the target so data will be inaccurate The cone of ultrasound extends downward from the centre line If the target is at a distance from the sensor the work surface maybe detected rather than the target Try raising the sensor higher If using the Motion sensor with a track use Meters or Test Mode first to check the target can be detected along the whole length of the track and adjust as necessary If the room you are using the Motion sensor in has a lot of hard sound reflecting surfaces ultrasound can bounce around the room If this happens try placing cloth horizontally just in front of and below the Motion sensor s transducer Balls made from foam or balls smaller than 5 cm diameter may not be detected
13. s Solid plastic tray Office type partitions notice boards Brick walls Soft fluffy folded or draped fabric or clothing i Use Meter or Test Mode to determine if an object is providing a good reflection e The Motion sensor is calibrated for measurements of g distance to be made from the centre of the perforated LN cover of the transducer Taneauesr f e The minimum distance between the object and C the Motion sensor should be 0 15 m 15cm 6 Red signal LED Hi inches The circuit inside the Sensor needs to switch off after a pulse has been sent to allow the transducer to stop oscillating before it tries to detect the reflected signal E D e The further the object is from the Motion sensor the wider the detection cone becomes The best response is within 5 either side of the central line of the transducer At long distances stray objects can become more of a problem The Motion sensor leans back at a 6 angle to help prevent sound waves impacting a flat surface close to the sensor e When the Motion sensor is held in a clamp experiment to find the best angle of tilt and therefore the best echo e The sensitivity of the echo detection circuitry automatically increases in steps as time elapses before the echo returns This is to allow for echoes being weaker from distant Simart Motion sensor objects This increase in step can produce a slight change in distance measurement that maybe become notice
14. the currently selected range If the range is not suitable for your investigation set to the correct range see page 3 The red signal LED on the Motion sensor will only light when the EASYSENSE unit is powered and a signal has been reflected from the object It will emit a clicking sound each time a pulse is sent Note The red signal LED on the Motion Sensor is not a power on indicator it is used to indicate that a reflected signal has been received from an object The Motion Sensor will start to pulse at approximately 50 pulses per second every 20 ms If the time for a pulse to reflect off an object is longer than 20 ms when the object is over 2 metres away pulses will slow Simart Motion sensor Ranges The Motion sensor has 8 ranges e A Walk range that can record distances from 0 15 to a maximum of 3 metre This range is best used for experiments that involve walking back and forward in front of the sensor The data is automatically smoothed to a higher level than other ranges by 4 levels of rolling average instead of 2 e 3 Distance ranges that have a maximum limit of 1 metre 2 metre and 4 metre e 3 Distance ranges that record to the sensor s maximum 8 m 800 cm and 300 inches e A Time range that measures the time taken for a pulse to travel to a target and back With some EASYSENSE units it is possible to set the range from the unit Please refer to the EASYSENSE unit s user manual To alter the range in th
15. ty and acceleration of the moving person See below Using a start condition to trigger logging can be advantageous e g distance rises above 0 5 m The Predict function of the EasySense software can be used to create a preset line for the students to try to follow See page 11 Approach up to 15 cm from the transducer To create Velocity or Acceleration data 1 Use Smoothing Tools menu on recorded Distance data 2 Select Post log or Pre log Function from the Tools menu e Use Pre log prior to the distance data being recorded Velocity or Acceleration data will be created as logging progresses Pre log Function Selection e Use Post log when data has already been recorded Select a Preset function or a Formula Preset function Motion ele Velocity Acceleration from position data or distance data Acceleration from Velocity data first derivative 3 Select Preset function and then Motion 4 From the drop down menu select eean anaa S Pendulum Linear Displacement e ith e r Vel OC i ty O r Acce erati O n fro m Displacement from Y elocit pos it i Oo n d ata O r d i sta n ce d ata Z Velocity calculated from position distance or displacement data first derivative Enter the units as appropriate e g Linear Motion units m m s cm cm s mm mms in ins CI j ck O n N ext Pendulum units deg deg s 10 Simart Motion sensor Select the Distance chann
16. upply If you intend to collect data remotely check the batteries in the logger are fully charged before you start This sensor s power requirement makes it unsuitable for use with the Flash Logger Link and V1 2 or less of the Q3 and Q5 loggers If data has spikes or appears inaccurate Spikes occur when the echo is lost Check the following list in particular the alignment of the sensor to the target The transducer is very directional e Check the target is more than 0 15 m 15 cm 6 inches from the Motion sensor e The maximum distance 8 m is reached under ideal conditions e g for a large flat wall perpendicular to the sensor For smaller objects or non flat surfaces the maximum detection distance will be shorter e Other sound sources can cause a problem if they produce ultrasonic waves in the same frequency range around 50 kHz e g air track blowers air exiting holes on an air track motors fans etc e The path of sound waves is bent by wind If the air is turbulent or fluctuating e g on a windy day or by heat from a hot object measurements will be affected e Check that the reflecting surface reflects squarely Flat objects must be perpendicular to the waves e Try increasing the strength of the target s reflection by increasing the size of the target area e Try altering the reflective property of the target e g by attaching a piece of stiff card e When studying a person s movement they may not supply a str
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