April 6th, 2004: Lab Day 10 Semester 2

Where: Jobst 248

What got done:

I have been playing around with some ideas for the light sensors for the past day or so and I have come up with a design. I am planning to use a photoresistor in the feedback loop of a non inverting op amp. I set the input voltage to about .5V. The photo resistor ranges between 100 ohms and 50k ohms depending on light level. This will make the brightest of light at .5V and complete dark at nearly 3V. In lab I tested the setup in real life. It turns out that the photoresistor can obtain a greater impedance than 50k and consequently drives the output to more than 3 volts. To protect the microcontroller I built a simple interface protection using a few diodes to clamp the voltage. The circuit seems to work quite well. I also finished the rest of the bug fabrication. I mounted all the boards and sensors. I wired headers for the contact switches and for the light sensors. Ajax has made a motor test routine for the motors and has successfully interfaced the microcontroller with the rest of the hardware. The voltage regulator and A/D appear to be working properly on the board.

What needs doing:

What still needs to be done? Well we still need to mount the light sensors onto the solar array and make a more convenient wire connector for them. We also need to implement the software associated with the light sensors and contact switches. The expo is coming up next week so we will also have to make a presentation board of some sort.