Week 9 Progress Report

This week, we tested the polymer-dispersed liquid crystal display that we made the previous week. A variable AC power supply was used to supply power at approximately 100 volts to the PDLCD, and while it did not work as well as desired, it was shown that the constructed display was capable of switching from opaque to transparent when enough current was run through it.

We also worked on troubleshooting the wiring for the PDLCD. It was discovered that the 3:8 decoders' negative enables needed to be wired to ground as opposed to left unwired. There was also a problem in which some of the LEDs were lit when there was no power.

Week 8 Progress Report

This week, the programming for the Arduino was completed.

The wiring was also completed, but some complications arose in which the breadboard did not have connectivity where it should have and had connectivity where it shouldn't have been.

The PDLCD was also made by cutting a sheet of ITO-coated plastic with 3 seven-segment displays and 1 one-segment display, but it was discovered after the display was made that we had forgotten to also make room for the colon and AM/PM displays. Afterwards, two grams of PDLC were made by mixing 1.4 grams of Merck nematic LC mixture BL-E7 and 0.6 grams of Norland Optical Adhesive 65. The PDLC was then mixed with glass spacers and spread on the sheet of ITO-coated plastic that had been cut and sandwiched with another sheet of ITO-coated plastic. Finally, the PDLCD was cured by exposing it to a mercury lamp.

Week 7 Progress Report

This week, the work on the ITO-coated plastic began, and is expected to be completed before work begins for week 8. In week 8, we expect to create the PDLCD in the lab.

This week we received our shipments of 3:8 decoders and an Arduino Uno. The first order of business was to put all of the decoders into their proper places in the breadboard second from the top. Then we collected  several JK flip-flops and placed them in the top row. The clock was wired to the output of the decoders and the J was wired to the signal wire and the K was wired to the ~signal wire, for each JK flip-flops. Since the JK flip flops are negative edge triggered, the enable for the decoders will have to be turned on then off to change the value of the JK flip-flops. All of this was not quite completed and is expected to be completed during the next week. These flip-flops will then be wired to transistors, which will allow or restrict power to the PDLCD segments.

This week we also began programming the Arduino Uno. We began by importing the Time library which will allow the Arduino to increment its time by one second every second. Then we set up the code to one by one examine each of the digital flip-flops and then make its value the proper value based on the current time of the Arduino's clock. Then, the Arduino will check two inputs, one of which is implemented to add one minute to the Arduino's current time, while the other one adds one hour to the Arduino's time. Each of these buttons has been programatically made to be latching. This means that instead of adding one to the time on each iteration of the Arduino, it adds one for each time the button is pressed and no more.

Week 6 Progress Report

This week, we ordered 3:8 decoders and an Arduino starter kit for $3 and $37 respectively, not including shipping.

More wiring was completed. Specifically the inputs were processed in such a way that one of the four sets of inputs will be selected by the first 2 bits of the 5 bit selector and the other three bits will select which output of that decoder will be selected. After the signal comes out of the decoders it wll go into digital flip-flops, which will preserve state and then finally on to the transisters to allow power to pass to the PDLCD.

The layout for the clock was also drawn onto the ITO-coated plastic for etching next week. The layout leaves space for future wiring around the borders. In the right corner, there is a circle that will be the AM/PM indicator. The tens digit for the hours is a one-segment display followed by a seven-segment display for the hours' ones digit. The hours and minutes are separated by a colon, which will be two circles. On the right of the colon, there are two seven-segment displays, one each for the minutes' tens and ones digits.

Week 5 Progress Report

This week, we began our implementing new design. This design relies on the use of demultiplexers and digital flip flops. In this way, it is possible to have outputs, which preserve their state. This allows us to simplify the logic significantly; however, this has some downsides. Since we are only changing the state of one output at a time, this will cause some lag when more than one output has to be changed at a time. Hopefully, the Arduino will be able to change the outputs quickly enough that the lag will not be noticable to the human eye. We also wrote the procedure in order to create the PDLCD material during the next week.

Week 4 Progress Report

This week, a breadboard, wire, and IC logic gates were obtained and wiring for the clock display was begun.

A setback was run into when it was found that the university could only supply us with AND, NOR, NOT, and NAND gates. The initial logic was designed using AND, OR, and NOT gates, and the lack of OR gates proved tedious to overcome.

We began considering alternatives to the described system, such as using a combination of multiplexers, decoders, and digital flip-flops. If this system is implemented, then only 5 outputs will have to be used, instead of 12.

Week 3 Progress Report

This week, we began work on laying out the electrical diagram for our clock.

Several clock designs were proposed. One of the most interesting involved forming a dome or sphere from the ITO coated plastic; it involved forming a sphere based on Goode homolosine projections that possibly would be rotated by a motor, but this design was deemed complicated and inefficient. General concensus was that the clock would most likely be a flat sheet of ITO coated plastic, but the group would like the incorporate better aesthetics if possible during or after the clock's construction.

Week 2 Progress Report

This week, the clock design has been agreed upon. The design will consist of a piece of PDLCD with numbers etched into it. The clock will be made to display numbers as needed with an electric current.

The PDLCD will consist of three main elements. The ITO coated glass from KINTEC costs approximately $10 for a sheet of 4 in x 6 in [2]. The polymer will be Norland Optical Adhesive 65, which will cost about $17 for 10 grams [4]. The liquid crystal that will be used is Merck nematic LC mixture BL-E7. The price could not be found.

The controller that will be used will be an Arduino Uno R3, which will cost approximately $30, with an expected cost breakdown of $10 per person [3].