Computer Interfacing
Computer Lab Interfaces
Although there are up to four different ways to collect data with
IBM-compatible computers and several with the Macintosh, only
two are recommended for use in biology classes. These vary in
types of inputs, data collection rate, resolution, and price.
ULI
Vernier's Universal Laboratory Interface can be used on both Macintosh
and IBM compatible computers. Although it supports both analog
and digital inputs, I expect that the analog input will be used
the majority of the time in biology. At data rates below 4000
samples per second, all channels on the newer devices have 12-bit
resolution -- the older versions are limited to 10-bit resolution
. The ULI Interface supports all the sensors that the Serial Box
can use, but is also capable of doing some things the Serial Box
Interface cannot do. Specifically, it supports:
- Fast analog data collection (for studying the sound waves
of cricket chirps with a microphone, for example)
- Motion Detectors
- Radiation counting
If you want to use your Macintosh in all subject areas (especially
physics), get the ULI.
Serial Interface
The Serial Box Interface will only collect two channels of analog
signals. This is great in a biology class, since almost all of
the probes and sensors I use are analog devices. The main advantage
is it's low cost. It has a slower response time than the ULI,
taking only 50 readings per sec or less. Most of the sensors I
use have a response time MUCH longer than this, however, so this
is not much of a concern. All channels have 12-bit resolution.
The Serial Box Interface can be powered by an internal battery
pack so it can be used with a laptop computer for remote data
collection. This is great for field work, if you don't have the
CBL systems.
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