Jeff Action Items

1-25-07

Currently working on circuitry to enable signal transmission between sensor and base unit.  Looking into Pulse Width Modulation to increase transmission efficiency.

2-02-07

Loyd and I are both focusing on the transmitter. 

2-10-07

A transmission method based on amplitude modulation has been chosen to test.  In this next week, we will buy the additional needed components and build a transmitter/receiver pair. 

Additional components to be bought: Crystal oscillator ~ $0.25
                                                             Two telescoping test antennas ~ $10.00

 2-15-07

We've decided to transmit using Amplitude Modulation.  This will be done using a ring modulator.  We are currently constructing said ring modulator.

2-22-07

Ring Modulator is complete.  This week, I will build a band pass filter to clean up the A.M. signal and conduct some tests to confirm transmission. 

3-28-07

The original transmission plan was abandoned, to be replaced by a more optimized solution.  The Xbee transmitter/receiver pair was chosen for its low power operation and effective transmission range.  This will elliminate the need for a ring modulator on the transmitting end.  Instead, we will use analog to digital conversion  circuitry to interface the variable oscillator with the transmitter chip.  I am currently putting together the PCB layout and making arrangements to power the prototype with a rechargeable lithium ion battery cell.