Kevin has been writing some code for the microprocessor and Alan has wired a prototype on a protoboard. To get some practice assembling a unit, Tom attempts to make one with the parts we just received.

Here is a picture of the second prototype.
This prototype was useful to demonstrate an test the microprocessors code.
  These are some pictures of the control panels. The far left picture shows the control panels connected to the protoboard. The middle picture is the Multi-Use station. The right picture is the In-Room station.
             We learned a few things when building the prototype.
We did not realize that the LED's were going to exceed the current limitations of our processor. Luckily we determined this before assembling and applying power. Using transistors and re-assigning LED's fixed this.
2. Our buttons are not going to work! They are very fragile and come loose from their mounting. The problem was that we had to custom build plungers that connect to the buttons. This was very complex and time consuming. We will need new buttons.
3. The 7-segment displays look a little vulnerable. We may need to build some sort of clear cover for them.

During the week we attempted to test the code and nothing worked. Apparently the prototype needed an external oscillator to function. We eventually get a 6MHz oscillator connected. Then we find that the program does not respond to the pushbuttons. Kevin and Alan work diligently on this problem and get a demonstration working by Saturday.

There was a design change to make the LED's active low. This required rewiring the prototype. Also, a change was made to have each LED controlled by separate I/O pins. Tom makes the changes and builds another simple prototype on a protoboard so that the communication can be tested. Also the RS485 communication chips are added. Both sets of protoboarded components are connected together to make one large protoboard
Kevin has updated the software to match the wiring changes. He also worked many of the bugs out of his code.
It is spring break but Bill and Tom work hard to build a working unit. It is extremely difficult to do since everything needs to fit on small circuit boards behind the light switch cover. The multi-use station requires at least two circuit boards in a stacked configuration. Here are some pictures.
Today Tom makes several clear plastic covers to protect the 7-segment displays. Tom has been working during this past week on building a vacuum form tool. This tool is used to clamp a sheet of plastic. This plastic is then heated until it is pliable enough to mold into a desired shape. A vacuum is then applied to shape the plastic to the mold. In our case the dual 7-segment displays are used as the mold. When finished, the plastic becomes a protective shell for the display. Click on the image to see more of this process.