Crystal Oscillator

Working title: Crystal sensor with Superheterodyne capabilities

Thesis Objectives: •Make a crystal oscillator that will display the oscillation of an A/T cut quartz crystal as voltage. •Use a microcontroller to record the frequency difference between the reference crystal and the exposed crystal. •Examine the effects on the crystal by various elements, such as salted water and tomato sauce.

Working title: Crystal sensor with Superheterodyne capabilities Crystals - Tiny wafers that oscillate at almost accurate frequencies. - Very sensitive to outside elements. - Can be used to detect changes while in contact to the environment. Current results: •Used a Colpitts oscillator found on the net. It displayed good results. It was used all the way. •Torroids were wound to make a superheterodyne circuit, subtracting the frequency from a reference frequency and an experiment crystal. Difference of frequency was acquired. •Found circuit for dividing the frequency of the reference crystal, whose quotient will be used as reference frequency for the second stage of frequency subtraction. It functioned well on simulation.

Working title: Crystal sensor with Superheterodyne capabilities Next tasks: •Create a program from the microcontroller that displays the numerical value of the difference frequency. • •Feed the output from the hardware into the program and check the results with the values acquired from an oscilloscope. • •Experiment the hardware with several liquids, and hopefully derive a correlation between frequency and another factor.

Adviser:

Celso B. Co Members: Miguel Sobrio Lean Sze Carlo Chico