Participants Alex Hastings, Eric Chang, Steven Wen, Clement Lin, Danny Li Sponsor:Hewlett Packard Faculty Advisor:Guest

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ParticipantsAlex Hastings, Eric Chang, Steven
Wen, Clement Lin, Danny LiSponsorHewlett
Packard Faculty AdvisorGuest

• Objective
• Our project is to build a portable chemical
  analyzer for use with Hewlett Packards iPAQ PDA
  device. This chemical analyzer measures three
  characteristics of a liquid sample temperature,
  conductivity, and light absorption of red, blue,
  and green light.
• Background
• Our circuitry interfaces with the iPAQ using
  Hewlett Packards compact flash expansion pack,
  and C-Cubeds Compact Flash Data Acquisition
  card. Our software for the iPAQ has been
  developed in embedded visual C.

Results/Status The chemical analyzer measures
temperature, conductivity and light transmission
of different liquids by measuring voltage outputs
from our sensors. By applying the voltage drop
across the liquid, and measuring the resulting
current, we can determine the conductivity of a
sample. By sending red, green, and blue light
through the liquid and sensing how much is lost,
we can determine how much light is absorbed by
the liquid. Combined with our developed software,
we are be able to observe different measurements
of different liquids using the iPAQ.
Methodology Approach We built our device to
run with the HP H5450 iPAQ. In addition, it
requires an HP compact flash iPAQ expansion pack,
and the C-Cubed Compact Flash Data Acquisition
card to operate. We designed a specially-shaped
circuit board featuring a combination of
commercially available chips and custom-built
sensors to make our measurements. The raw output
of our measurements is sent to the DAQ card in
voltage readings, which are then converted into
the proper units for each measurement by our
software.
Conclusion The chemPAQ Portable Chemical
Analyzer is a small and convenient handheld
package that can be easily taken anywhere to test
the properties of different liquids. Knowing the
temperature, conductivity, and light absorption
of a liquid would give a general idea of what the
unknown liquid is, possibly telling if its
hazardous or safe. The Portable Chemical Analyzer
has been a very fun and interesting project for
us. We were able to design our own software and
circuit board to make it work with the current HP
iPAQ model (H5450).