Date: Wed, 16 Mar 2005 16:57:34 -0600

Author: Paul Nord

Subject: Re: Reflectors for motion detectors


Any alternative technologies out there? Laser rangers?


On Wednesday, March 16, 2005, at 03:10 PM, Papp, James J wrote:

> I have resorted to taping a 3x5 note card on the close face of the
> cart when adjusting the sensor does not work. I suspect the angle of
> the sensor relative to the cart face is the key - when I can get that
> right, there are no skips or jumps. Getting the transmission as close
> to perpendicular as possible seems to be the key. When I am a few (5
> to 10) degrees high or off to one side, skips and jumps sometimes
> occur. The note card sometimes (not always) fixes the problem.
> I am pretty sure it is because the Pasco carts have right angle
> surface details on the front, back, and top of the cart, that
> influence the reflections, although I have not figured out why the
> skips are so much larger than the face details, but smaller than the
> length of the cart. Or why the note card only works some of the time.
> Next free moment...
> Good luck!
> Jim Papp
> -----Original Message-----
> From: Marc Kossover []
> Sent: Wednesday, March 16, 2005 8:02 AM
> To:
> Subject: Reflectors for motion detectors
> Howdy-
> I know that many of you all use the Vernier (and
> Pasco) Motion Detectors in class. I was having trouble
> getting good reflections off of the Pasco Carts. My
> first solution was placing a reflector (a piece of
> cardboard) in the cart. See
> .
> However, the reflection would sometimes bounce off of
> the the front of the cart and sometimes off of the
> cart, causing weird jumps in the data.
> I figured that the reflector would work better if it
> were placed on the front of the cart, but how to make
> it stay? I tried tape, but it left a mess when
> removed. Rubber bands got out of alignment, and the
> card would drag on the track.
> The trick was taping a couple of paper clips to the
> back of the card and then using the magnets built into
> the carts for elastic collisions to hold on the card.
> See
> Works like a charm, and we now get super smooth data.
> Marc "Zeke" Kossover
> The Jewish Community High School of the Bay
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From Wed Mar 16 18:31:30 2005