Week 13
Project Update

This week I tried to think about all the hardware I would need for my final project. First, the case...

The plan for the case was to lasercut plywood into slices that I could glue/connect together to form the case. I am still waiting on the plywood to get in, but I wanted to figure out if the case would work with the rest of my design, so I cut a test case out of acrylic. I didn't run into any issues and I think it looks pretty good.

Having a physical model of the case did make me realize there are two issues with the design. First, the LED display board that I made is too big to fit in the case, so I will have to re-design one of them. Second, I have holes for the buttons, but nothing in the case to hold them in place, so I'll have to design something for that.

Next on the hardware list was the display. In one of the previous weeks, I made an LED array that formed a seven-segment clock display. It didn't work because there wasn't enough current to drive three LEDs in series. So this week, I made a intermediate board with N and P transistors to drive the LEDs. This board sits between the control board and the LED array board to provide more current to the LEDs.

I tested this setup and it only semi-worked. It worked better than last week, as I was able to see that the three LEDs in series were lighting up, but not all of the LED segments would light. Also, the brightness varied between different parts of the array. Finally, there is an issue with the drivers getting too hot and causing reliability problems (even though I added some current limiting resistors).

The final piece of hardware that I need for my clock is input buttons. I want to make some curved buttons to go with the case that I designed, so I thought the best way to do this would be molding. Another option could be cutting slices on the lasercutter. I made Solidworks models for the buttons I want to design, but haven't been able to convert them to PNG files yet.

The slider switch is the final problem I am running into right now. I am not sure what would be the best way to make this. I know we did the step response input that was supposed to be able to work as a slider, but when I tried to make this I couldn't get a reliable response.

Any suggestions would be very welcome...