Objective

Think up an ambient display idea and prototype it using Handy Cricket. The demonstration must make some kind of TCP connection to an existing Web Server, parse the data received from the server, and then create some kind of tangible/kinesthetic/audible/etc representation of this on-line data.

Design

I started the lab not knowing what technologies I was going to use and to what extent. First I needed to access an existing web server to retrieve some information. I decided to get the local temperature from a local weather website. After spending days analyzing what programming language I was going to utilize towards this goal, I decided to go with Perl scripting language for its web access capability and also for its great parsing ability.

The main part of the code was written in perl, file temper.pl. This code makes a call to curl to access a web page and store it onto a file. The file is then parsed for the temperature data. This temperature data dictates what value to send to the serial port connected to the cricket. The actual code that does the serial port communication is written in C, file serial.c, with its executable named swr.exe. This serial code is called from perl, where a value is sent to the cricket.

The cricket code is written in cricket logo and found in tdir.txt. All it does is wait for a value of 6, and once received changes the direction of the motor rotation which is connected to the cricket. The motor is attached to a wheel which turns in free space. What the wheel turning actually indicates is the change in temperature or directionality of temperature change. Thus if consecutive temperature reads have increasing value the wheel turns one way and for decreasing values the wheel turns the other way. This basically notifies the user whether the temperature is warming up or cooling down at any point in time.

The actual calculations on the temperature values is done in the perl code and only when the temperature changes direction does it send a message to the cricket to reverse direction of the wheel. I found this to be a very interesting application as one may want to know which way the temperature is heading.