Project Overview

Problem Overview

Many methods have been devised throughout the history of mankind in order to aid us in telling time. The Egyptians developed obelisks and sundisks to utilize the sun's position to tell the time, and then the merkhet to read the stars to tell the time [1]. Afterwards, they developed clepsydras, the first mechanized form of clocks that didn't rely on the sun or the stars to tell time; it just needed a steady supply of water. Unfortunately, they were too large for the average person to keep in their home. It was not until the early 1500s that the spring-based clock was invented, becoming the precursor to accurate timekeeping [1]. It also allowed clocks to become common household items, being much smaller in size; however, they can also be very expensive. As such, there must be a way to tell time accurately while still keeping it affordable and relatively small.

Design Constraints

The proposed clock must be capable of running on both batteries and from a standard wall outlet. It also needs to be a reasonable size, which can be defined as no bigger than 2' x 2' x 1'. The project must be able to take inputs from the user so that it can be set to the current time, and there must be a display, of the polymer dispersed liquid crystal variety, which is able to communicate the current time to humans in a readable fashion. In addition, the clock must be capable of either measuring or inferring time passage and then updating the time display according.

Pre-Existing Solutions

There exists a variety of common solutions to this problem. Common examples of how humans tell time include sundials, moon-based estimations, north-star time determiners, mechanical clocks, electric clocks, atomic clocks, web-interfaced clocks.

Design Goal

This project addresses the problem presented by keeping track of the current time as well as communicating the current time in a readable interface to the clock's user. This is neither a groundbreaking nor novel idea. The project's objective is not to reinvent the clock, but rather to gain knowledge so that we could construct more complicated systems which involve clocks.

Project Deliverables

By the end of week ten, we will have a piece of PDLCD glass with electrodes running to different sections of the glass. At first, the glass is opaque, but when a current is applied to different electrodes, corresponding sections of the PDLCD glass will become clear. A controller will be attached to these electrodes and will be able to record the passing of time and modify the current going to the electrodes to make the PDLCD glass become opaque in a pattern which represents the current time in the conventional digital way.

Project Schedule

• We expected to finish our design by the end of week three. 
• By week four we will acquire the Arduino and begin writing the programs to manipulate the electricity going towards various sections of the clock display. 
• At the end of week five we will have completed the program for the Arduino. 
• Later, during week six we will construct the PDLCD glass. 
• Finally, during weeks seven and eight we will assemble the clock. 
• Weeks nine and ten will be set aside to fix any unforseen problems with the project and to add additional features such as an alarm, if there is adequate time.

Project Budget

The major expense involved in this project is the aquisition of a controller. We decided to use an Arduino Uno R3, which will cost approximately $30. The PDLCD consists of three things: ITO coated glass, a polymer, and liquid crystal. The ITO glass costs approximately $10. The polymer, Norlad Optical Adhesive number 65, costs approximately $17 dollars for the quantity that we need. Finally, the Merck nematic LC mixture BL-E7, requires a quoted price, and the cost is yet to be determined.