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

An amplifier may be required Given temperature range produces a signal within 1v

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 group has been co-operating well due in no small part to the excellent Project managers Next step will be two implement the temperatore and humidity transducers The Clock and the Analg / Digital Converter have been constructod and vigorosly tested