March 30nd, 2004: Lab Day 9 Semester 2

Where: Jobst 248

What got done:

Little more got accomplished today. We clayed out the board for the microcontroller and setup the regulator and A/D. We made power and ground interconnects between the motor and control board and got the communication header connected. We have yet to actually get the two boards interfaced. There are still some software issues that we have to overcome. I have also discovered a problem in the battery charger. It seems that the directional diodes that lead to the load output are not strong enough to hand the the power dissipation. The diodes work fine for about 5 or 6 minutes and then the forward voltage dives to 1.8 Volts. I'll have to find a replacement part with higher current ratings. I also explored what we need to use for light sensors. For the sake of saving power I think we can get by with only two sensors. I've come up with a system that will work using a resistor and photo transistor. I still need to calculate a resistor that will keep the signal within operable ranges. I am lacking data sheets for the photo transistors and I am under the impression that they do not operate in a linear fashion so I may have to experimentally determine values. Once I have chosen the resistors I'll find the closest resistor that we have with a 1% tolerance. I have already discussed mounting issues with Nick and we have come up with an acceptable method that will require little fabrication.

What needs doing:

I was hoping to be farther along at this point but I need to finish the sensor design and get them mounted. We also are still lacking contact switches so I need to search through the components we have and if it can be modified to work for our purpose. Once that is done we need to get signals in and out of the microcontroller.