March 16th, 2004: Spring Break

Where: Jobst 248

What got done:

This week is spring break and being the dedicated student that I am I came into lab anyway. This log is actually for a few days over break where I spent a few afternoons working. I decided to change the battery configuration to give us better battery life. I will still be using a 6V configuration but I will do it with four AA Lithium batteries instead of the button cells. This will give us better current capabilities and longer battery life over all. I rans some Pspice simulations of the charging circuit and it should theoretcially work with the new battery setup as it did with the old one. Another siginificant change that was made was the component ordering. I have the solar cells running directly into the charger now. Off of the charger the regulator is connected and then into the Hbridge circuits. I have also reconfigured the Voltage regulator to provide us with a low voltage warning from the batteries. If the batteries are near drop out a Low Batt signal will drop low. With some software we can do alot with this signal. We also have an out of regulation warning flag that operates in the same fashion as the Low Batt signal. This will let us know when the regulator is about to die completeley. I setup all of the circuits in order and tested them to make sure everything worked fine and it seemed to. Satisfied with the results I have begun to wire wrap all three circuits together for final implementation. On the issue of construction our assistant lab director Nick was a great help mounting our solar pannels to a sturdy board as well as the motors. We have the entire bug pretty much fabricated. He also gave me a hand and double checked the current voltage output of the solar panels. In full sun the panels put out 1.5 Amps at 8 Volts. This is about five times the estimated power usage. Inside however the panels put out little more than 2 volts and unacceptable current.

What needs doing:

I need to finish getting the circuits wire wrapped and put onto the bug itself. I will need to make sure the status lines and control lines interface with the microcontroller properly. Ajax has already written a small motor test routine to test the possible movement combinations. We also need to decide on what light sensors we will use and find or fabricate contact sensors. I also want to get the IR stuff hammered out by the end of next week.