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Motion Detector Troubleshooting and FAQs

About this FAQ

  • Created Feb 3, 2005
  • Updated Sep 26, 2013
  • Article #1374

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Motion Detector, order code MD-BTD, $79
Specifications and User Guide

There are two Motion Sensor models:
Motion Detector 1 (MDO-BTD) - blue plastic, two LEDs below and to the left/right of the gold screen.
Motion Detector 2 (MD-BTD) - green plastic, one LED on the right below the gold screen, track mode switch inside pivoting head. (Began shipping 1/2005.)

The sensor portion of Go!Motion, order code GO-MOT, $109 is functionally identical to and interchangeable with the Motion Detector 2. For use with LabPro, the Digital Sensor Cable, order code MDC-BTD, $5 is needed. For use with calculators, four AA batteries are required.

In addition, there are two models from Texas Instruments that are functionally similar to the Motion Detector:
CBR 2, order code CBR2, $99 - white and gray plastic, has track mode switch inside pivoting head. The CBR2 is functionally identical to the Go!Motion. For use with calculators, four AA batteries are required unless a CBL2 interface is also used.
CBR - Dark gray plastic. The sensor of the CBR is functionally identical to that in the Motion Detector 1.

TROUBLESHOOTING
- Test 1: Does a green LED light up after it is plugged-in and autoID'd by a data-collection program?
- Test 2: When you start data collection, do you hear a clicking from the Motion Detector? If not, the sensor may be defective.
- Test 3: Find a wall with no desks, chairs, doors, or other obstructions within a 2 m field. Hold the motion detector in your hand, 0.5 m from the wall with the gold disc pointing directly at the wall. Do you get the expected 0.5 m reading? Back off to 1.0 m. Do you get 1.0 m? Back further off to 1.5 m. Do you get 1.5 m?
- Test 4: Motion Detectors use ultrasound to measure position. Other sources of ultrasound may be interfering with the signal. Those sources include air tracks, CRT computer monitors, fluorescent lights, and power distribution panels. Identifying these sources can be challenging. You may have to resort to moving the Motion Detector away from interfering equipment. In the case of noisy fluorescent lights, turn them off, but we rarely see this problem.
- Test 5: Use a cable from a working Motion Detector in place of the cable from the non-working unit. The cable may be defective.

- Tip 1: The optimum collection rate is 20 pts/second.
- Tip 2: Clear all objects within the 30 degree cone.
- Tip 3: If you are monitoring the motion of objects on a table or track, tilt the head up slightly.
- Tip 4: Use the Track mode switch when using a cart on track. Use Normal mode for all other applications. It does no harm to try the other mode.
- Tip 5: Increase target's area.
- Tip 6: Noisy velocity data: increase the number of points used for derivative calculations. See TIL 2331: How do I adjust the number of points used in derivative calculations?
- Tip 7: The maximum sample rate that you can use for the motion detector is 50 Hz, which equates to a sample interval of 0.02 seconds. We do not recommend that setting as it tends to produce noisy data.

RELATED TIL ENTRIES
TIL 5: Why am I getting Motion Detector readings that are noisy or max out at a certain distance?
TIL 19: Can I use 2 motion detectors with my Vernier Interface?
TIL 2968: Why won't my Motion Detector (or other digital sensor) plug into the channels of my LabQuest 2?
TIL 410: Can you create new match files for Logger Pro?
TIL 405: Can I use a PASCO motion detector with the LabQuest, LabPro, CBL, or ULI interfaces?
TIL 649: How do I calibrate a MPLI Motion Detector?
TIL 459: Why don't I get a freefall acceleration value of 9.8 m/s^2 when using a motion detector?
TIL 318: Should I get a Motion Detector or a CBR?
TIL 1001: How do you create new match files for MacMotion or Motion?
TIL 1036: Will your Motion Detector show the speed of a (car, baseball, racquetball)?
TIL 1205: My Motion Detector is not collecting data with DataMate and LabPro.
TIL 1914: My motion detector still reads 0.004 m after zeroing.
TIL 1938: Should I use a photogate or a Motion Detector?
TIL 2053: How do I improve the results from a Motion Detector with an air track?
TIL 2120: How can I collect data from a photogate and a motion detector data at the same time in Logger Pro?
TIL 1011: How does Logger Pro calculate velocity and acceleration from Motion Detector data?
TIL 2655: A mass fell into my Motion Detector and dented the screen. Can the gold mesh screen be repaired?
TIL 2668: Can I do Graph Matching with my Motion Detectors and TI calculators?
TIL 2698: Why does my data table have holes (empty cells) in it?
TIL 2961: How does a Vernier Motion Detector work (electrically)?
TIL 2972: Is there a way to calibrate the Motion Detector?

SPECIFICATIONS
- order code: MD-BTD
- ultrasound frequency: 50 kHz
- resolution: 1 mm
- accuracy: 2 mm
- range: MD-BTD - 0.15 m to 6 m
MDO-BTD - 0.5 m to 6 m
- speed of ultrasound used to calculate distance: 343 m/s *
- power: 51 mA while running

*Adjusting the "temperature" setting in Logger Pro changes this value. Speed increases with temperature. We apply a linear correction such that a 1°C change of temperature is equal to 60 cm/s change of speed of sound. The Go! Motion is more sophisticated because only it has a built-in temperature sensor and applies the correction automatically.

CALIBRATION
- Air temperature corrections are possible only in Logger Pro and Logger Lite in the Sensors dialog.

RELATED VERNIER PRODUCTS
- Motion Detector Clamp, order code MD-CLAMP, $7, order separately
- Digital Sensor Cable, order code MDC-BTD, $5, shipped with sensor
- Cable Motion Detector to MPLI, order code M-MDC, \Contact Us
- Cable Motion Detector to ULI, order code ULI-MDC, $5
- Motion Detector Bracket, order code MDB-VDS, $11
- Digital Extension Cable, order code EXT-BTD, $12, 2 m in length

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