Urgent vernier question

[linotas]

We are using our verners with motion detectors this morning and the teacher wants to set the distance for 3 m and it is defaulted at 1m. I can't for the life of me work out ho to change it. Any ideas?

[smiley]

Are you using the Go!Motion's?

[linotas]

No just the general motion sensor hooked up to the LabQuest

[smiley]

Check your PM

[smiley]

We just did a Yr12 Maths prac, in fact, using Motion Sensors, so here's what I learned the hard way, for anyone else wanting to use them.

1. Interference: If you have anything that can reflect the sound inside the "cone" of sound being sent from the Motion Detector, they will interfere. In fact, the sensor seems to detect whatever is closest. So you have to move everything in the way, including chairs desks etc.

2. Sensitivity: Check the switch bizzo behind the gold foil bit, and see if switching ti over changes your readings. Also, sometimes the "cone" can hit the floor, especially a lino one, and reflect sound in crazy directions, which causes ripples in the returning waves, making for some really freaky readings. Similarly, although this would be a QLD problem at the moment, overhead fans in rooms mess up the readings. Try doing the readings over carpet, or a blanket, to muffle the cross-fire, so to speak.

3. Reflections from whatever you actually want to read: If you've got kids or objects walking towards or away from the sensor, tape a square of flat cardboard to them in line with the centre line of the "cone" for a better reading. Obviously you can't do this with a ball, but maybe upsize to something bigger.

Hope that all helps.

[linotas]

Thanks everyone