Transcript Preliminary Design - Queen's University

Group 31Q
APSC 100
November 2 ,2002
Humidity Team
• Billy Smith
• Jacob Black
Temperature Team
• George McDonald
• Keith Brown
Supervised by…
• Dr. Geoff Lockwood
• Project Manager Bob
1. What We Learned
2. Our Goal
3. Preliminary Design
4. Components
5. Progress Report
Tutorial 1:
•How to construct circuits using bread-boards
•How to measure voltage, current, and resistance
(i.e. Resistance in parallel is R=1/R1 + 1/R2 + …1/Rn)
Tutorial 2:
•Learned about operational amplifiers so that we
can now add, subtract, integrate, and take the
square root of the signal
Tutorial 3:
•Gained Experience using an analog to digital
converter and seven segment displays
(i.e. Binary “1001” = Digital “9”)
• Learn to build and analyze simple circuits
• Produce an inexpnsive (<$200) weather
station suitable for home use
•Temperature Range will be –40 O C to
40 O C with accuracy within a degree
•Humidity will range from 0% to 100% with
accuracy within 2%
1) LM555 Timer/Square Wave Clock
2) AD7819 Analog to Digital Converter
3) Temperature Transducer Circuit
4) Humidity Transducer Circuit
1) LM555 Timer/Square
Wave Clock
2) AD7819 Analog to
Digital Converter
3) Temperature Transducer
Circuit
4) Humidity Transducer
Circuit
•Used to generate a square
root wave
•Sends an analog “clock”
signal to the AD converter
•Square root wave produces
intervals of reading and sampling
of the analog input signal
Using an AD789 linked with the DM9368 common
cathode display driver and a seven segment display
we can:
•Convert analog
signal from
transducers to a
binary code
•Convert binary code
into a digital display
(i.e. Temperature,
Humidity, Wind
Speed, and Pressure)
• LM35 precision
integrated-circuit
temperature sensor
• 0.5°C accuracy
guaranteeed (at +25°C)
• Rated for full -55° to
+150°C range
• Given temperature
range produces a
signal within 1v
• An amplifier may be
required
•HIH-3605-A transducer
circuit allows us to read
the relative humidity
•Send an analog signal to the
AD (Analog/Digital Circuit)
converter
•Transducer outputs
within target range of
AD Converter
• The Clock and the Analg / Digital Converter
have been constructod and vigorosly tested
• Next step will be two implement the temperatore
and humidity transducers
• The group has been co-operating well due in
no small part to the excellent Project managers