Motion Sensor - SmartSchool Systems
Contents
1. Product No 3705 Self powered type ait Ae RHEIN Ri N er as 2 Na 7 J Product No 3270 DATA HARVEST Y 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 Smart 0 TECHNOLOGY Motion Sensor Range 1 Distance 0 17 10 m Resolution 0 001 m 1 mm Range 2 Distance 17 1000 cm Resolution 0 1 cm Range 3 Distance 7 400 inches Resolution 0 1 inch Range 4 Time 1000 60 000 us Resolution 1 us DS 041 No 4 Data Harvest Freely photocopiable for use within the purchasers establishment Smart l Motion Sensor Contents qu WOU A 1 ONS CUI escaneo ee bie essehe 2 Power requirements ee u 3 TO Selle Tange wen ereignete 4 Practical information coconccccocccncoccnnconnnnconnnconnnnnonnnnononnnnnnnnnnnnnnnnnnnnninonnnineness 4 TINO Tango APPO ooo El E OE T E A mbar absan 8 Distance Velocity and Acceleration occccoccccoccocccnoccnnonanocnanocannocancnnanonnnns 11 A O E EEEE A ES EE 12 UN AA ee een nen ee 13 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 distan2. of a fault developing within the 12 month period the Sensor 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 Ltd are fully compliant with WEEE legislation and are 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 Notes
3. be made from the centre of the perforated cover of the transducer Transducer The minimum distance between the object and Red signal the Motion Sensor should be 0 17 m 17 cm LED 7 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 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 become more of a problem 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 objects This increase in step can produce a slight change in distance measurement that maybe become noticeable if the distance graph is differentiated Before starting an investigation use Meter or Test mode to determine if an object is providing a good reflection Flat objects can be masked if they are not perpendicular to the waves When the Motion Sensor is held in a clamp experiment to find the best angle of tilt and therefore the best echo 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 If you intend to collect remote data with t
4. ccurate e Check the object is at least 0 17 m 17 cm 7 inches from the Motion Sensor e Check for stationary objects e g tables chairs walls and floors that could be positioned in the cone of the ultrasound They maybe detected instead of the object especially if it is at a long distance Motion Sensor gt Motion Sensor gt IN The cone of ultrasound is IN detecting the work surface II before reaching the object I II so data will be inaccurate 11 The ultrasound is detecting the object so data will be correct e Other sound sources could 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 e Check that the reflecting surface reflects squarely Try to increase the strength of the reflection from the target by increasing the target area Smart i Motion Sensor e When studying a person s movement the target may not supply a strong enough reflection e g by wearing non acoustically reflective clothing Get the target to hold a large flat object in front of them as a reflector e The surface reflecting the signal needs to be silk finished If a surface is shiny or reflective it can reflect signals If the room has many sound reflecting surfaces ultrasound can bounce around the room If this happens try covering them with a cloth to reduce the reflec
5. ce of an object from the Sensor There are two types of Smart Q Motion Sensor 1 The original type Product No 3270 which takes the power it requires from the EASYSENSE unit This makes it unsuitable for use with the EASYSENSE Flash Logger Link and V1 2 or less of the Q3 and Q5 loggers 2 The self powered type Product No 3705 which has an integral battery pack and is supplied with a 12 V mains power supply This type can be used with any EASYSENSE unit including the EASYSENSE Flash Logger Link and V1 2 or less of the Q3 and Q5 loggers Both types of Motion Sensor are 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 a retort 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 into EASYSENSE when the Motion Sensor is connected Smart l Motion Sensor Connecting 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 Red forwards a E Mounting e Connect the other end of the cable dd thread to the input socket on the EASYSENSE unit e T
6. he EASYSENSE unit will detect that the Motion Sensor is connected and display values using the currently selected range If the range is not suitable for your i Insert the sensor cable with the Mounting locating arrow thread facing forwards investigation set to the correct range see page 4 e 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 the pulses will slow If your EASYSENSE unit goes into sleep mode nothing shown on LCD screen the red LED on the Motion sensor will turn off and the unit will stop sending a pulse until the unit wakes up to take a sample EASYSENSE Flash Logger users Power is only supplied to the inputs when data is being logged e g when the Start icon has been selected The Motion Sensor will not emit a clicking sound and the red signal LED will not light until a sample is taken Smart l Motion Sensor Power requirements Motion Sensor Product No 3270 This type of Motion Sens
7. he original unpowered Motion Sensor Product No 3270 check the batteries in the EASYSENSE unit are fully charged before you start The self powered type Product No 3705 will take most of its power from its batteries or power supply If the batteries in the Motion Sensor are fully discharged it will not function Attach the power supply and leave for a minimum of 10 minutes 5 Smart l Motion Sensor without taking samples Continue recording data with the power supply attached If the batteries are fully discharged it can take up to 7 hours to achieve full charge 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 1 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 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 If data appears ina
8. her 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 Distance 2 Speed me 5800 x 10 344 8 ms Smar The value of the velocity 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 Speed of sound in air 342 23 342 83 343 44 344 05 344 65 345 26 345 87 Motion Sensor Speed of sound in air 346 47 347 08 347 69 348 30 348 90 349 51 350 12 Investigations 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 motions 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 Smart l Motion Sensor Examples 1 Measuring gravity by free fall select an intersample time of 20 ms pre trigger greater than 30 cm Hold ba
9. lection Select a Preset function or a Formula Preset function Motion Velocity calculated as the first derivative Enter the units as appropriate e g Motion units m m s cm cm s in ins Pulley Linear rack mm units mm s Pendulum Angular Position Angular Speed units deg s Select Preset function and then Motion From the drop down menu select Velocity or Acceleration Second derivative of distance Velocity click on Next Select the Distance channel Next Enter the units as appropriate e g m m s cm cm s in in s Finish Acceleration second derivative of distance click on Next Select the Distance channel Next Enter the units as appropriate e g m m s s cm cm s s in in s s Finish Distance m Ball drop 2 000 1 800 4 1 600 Acceleration 1 400 1 200 4 N NT 1 000 NL 0 800 4 0 600 0 400 0 200 4 0 000 0 950 18 September 2006 14 40 48 Time ms 11 Smart Motion Sensor Presets Creating a Distance Preset Open Graph and select a suitable time span e g 10 seconds Select Sensor settings from the Display menu and alter the maximum to a more suitable number e g 5 00 m 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 Click with the right mouse button to finish the line Select Save Setup from the File menu E
10. ll about 10 cm below the Motion sensor click on Start release the ball and move hands away quickly 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 B Force Sensor gt J Smart l Motion Sensor 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 Cart with reflector fitted Motion Sensor attached to the Dynamics System track 4 Elastic and inelastic collisions using two Motion Sensors and carts on the Dynamics System track The two Motion Sensors need to be angled slightly away from the track about 12 so their ultrasound cones do not interfere 10 Smart Motion Sensor Distance Velocity and Acceleration To create a set of Velocity or Acceleration data 1 Select either Pre log function not available in Scope or Post log function from the Tools menu Use Pre log before the distance data has been recorded the set of Velocity or Acceleration data will be created as logging progresses Sli ccna eve of oda vacip Use Post log when the distance ace data has already been recorded Pre log Function Se
11. nter a name for the experiment and then a file name Creating Distance and Velocity Presets Select 2 from Number of Graphs in the Display menu Use Pre log from the Tools menu to create a Motion Velocity preset function alter the Y axis limits to Manual and change to a more suitable minimum amp maximum value e g 5 to 5 To display a different data set in each graph right click in the first graph area select Show or Hide Channels and deselect Velocity Repeat in the second graph but deselect Distance 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 Select Save Setup from the File menu Enter a name for the experiment and then a file name To open a preset From the Home page select Open Setup Select the setup you created from the list Click on Start to begin recording Distance m 5 000 4 500 4 000 3 500 3 000 2 500 2 000 1 500 1 000 0 500 0 000 00 0 05 0 Time ss A distance preset to copy 12 Smart i Motion Sensor 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 In the event
12. or takes the power it requires from the EASYSENSE unit If logging continuously for long periods connect the EASYSENSE unit to a mains power supply Motion Sensor Product No 3705 This Motion Sensor takes most of its power from its own batteries or from an attached mains power supply It will not function correctly unless either the internal batteries are charged or it is connected to a power supply Note The red signal LED on the front of the Motion Sensor is not used to indicate that the Motion Sensor is receiving power or that it is fully charged It is used to indicate that a reflected signal is being received from an object The mains power supply included with this Motion Sensor can perform two tasks 1 It can be used to re charge the Motion Sensors internal batteries in preparation for use away from mains power 2 It can be used to operate directly with the Motion Sensor connected to an EASYSENSE unit The specifications for the power supply are 12V DC optional unregulated and able to source at least 500 mA with a positive centre and negative outer pin Side view of the self powered Motion Sensor Product No 3705 Mounting thread Power socket When the self powered Motion Sensor is connected to the mains power supply the batteries will automatically be re charged unless the Motion Sensor is taking samples When taking samples the current from the power supply is diverted to provide power for sampling rather than cha
13. rging the batteries If the batteries are fully discharged attach the power supply and leave for a minimum of 10 minutes without taking samples Continue recording data with the power supply attached If the batteries are fully discharged it can take up to 7 hours to achieve full charge Although the main power consumption of the Motion Sensor is via its own batteries it will also utilise some power from the EASYSENSE unit or the Pocket PC if used with the Flash Logger Smart l Motion Sensor To set the range e Connect the Motion Sensor to the EASYSENSE unit Sensonflonge E e Start the EASYSENSE program and select one of the logging modes from the Home page e g EasyLog Select Sensor Config from the Settings menu Select Range e Select the Motion Sensor from the list it will be listed using its current range and click on the Change Sensor 2 Motion Sensor Range button e The current range will be highlighted Select the Deere N required range and click on OK e Close Sensor Config Click on New and then Finish for the change in range to be detected by the logging mode The range setting will be retained until changed by the user With some EASYSENSE units it is possible to set the range from the unit Please refer to the EASYSENSE unit s user manual Practical information Fastest Speed The maximum sample rate of the Motion Sensor is 50 Hz 20 ms If an interval between samples of les
14. s than 20 milliseconds is selected then either the set up will be rejected or the values obtained will default to zero Note The fastest speed that Version 1 0 1 3 Advanced users can log at is 40 Hz 25 ms The data from the Motion Sensor is not suitable for use with the Timing function or the Time amp Motion mode in the EASYSENSE software or data loggers These functions will only use data from switch type digital sensors The Motion Sensor emits pulses of ultrasonic sound waves from the gold foil of the transducer These waves will fill a cone that diverges at about 12 The Motion Sensor then listens for the echo of the ultrasonic waves returning When stood upright on a flat surface the Motion Sensor will lean back at a 6 angle This tilt allows the waves to run parallel with the horizontal surface Distance measured 12 Degrees Smart l Motion Sensor The EASYSENSE unit measures how long it takes for the ultrasonic waves to make the trip from the Motion Sensor to the object and back Using this time and speed in air the distance to the nearest object is determined 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 The Motion Sensor has been calibrated for measurements of distance to
15. tions e Sound absorbing surfaces such as acoustic ceiling tiles will produce errors as ultrasound will be absorbed e Balls made from foams or balls smaller than 5 cm diameter may not be detected 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 If values default to zero If an intersample time of less than 20 milliseconds is selected the values will default to zero If values default to maximum e When the red LED on the self powered Motion Sensor is flashing erratically or is off then it is possible that the batteries in the Motion Sensor are discharged Attach the power supply and leave for a minimum of 10 minutes without taking samples Continue recording data with the power supply attached a full recharge will take up to 7 hours Note f you are using the Motion Sensor with EASYSENSE Flash Logger the red light will not be lit until a recording has started e g by clicking on the Start icon in Graph e Check the power level in the EASYSENSE unit or the Pocket PC if used with Flash Logger Time range The Time range will measure the time taken for the pulse to travel to the object and then back again When used with the Time range selected 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 eit
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