Day 8: Sending Binary Messages With The Internet Simulator

Purpose: Students will develop a protocol to solve a problem.

Intro:
Yesterday you all made your own binary message devices. We learned that we could compose binary messages. In order to interpret the message we needed to know which signal meant A and which meant B. What we were really doing was beginning to develop a communication protocol. Today you’re going to develop a protocol to solve a problem.

 Journal Entry: Go online and write the definition of “Protocol” into your Journal. – Share with class.
A “protocol” is a set of rules about sending, receiving and interpreting binary messages.

Flashlight Binary Signal!
Instructions:

• One student is the transmitter and sends a message with a flashlight.
• One student is the receiver and decodes the binary message.

Show this video to the Student Transmitting the code with the flashlight.
Protocal:          On = A
                        Off = B
Test 1
“Imagine that you and your friend have made a binary signaling protocol using a flashlight. The light on is letter “A”, off is letter “B.”  (Code: B A B A B)

• The Transmitter shall pulse the flash light on and off at ~1 second intervals 4 times

 “Your friend sends you this message. What is being signaled here? Write down what you think the message says.”

Test 2
“Uh oh! Your friend realizes she actually made a mistake encoding the message from before and decides to re-send the message. Decode this new version of the message and write it down.”

• The Transmitter needs to pulse the flashlight on and off quickly twice at half second intervals, then three pulses at ~1 second intervals, then on and off quickly three times at half second intervals. (Code: BB A B A BB AA BB)

Class Discussion

• Did the Receiver have enough information to decode the transmitted information?
• Did the second message make the Receiver rethink your answer to the first question? Did you want to change your answer to the first question?
• Should the protocol be rewritten? If so, how? (Time & Synchronization??)

Journal Entry: Define Bit? (“Bit” is short for binary digit.)
Question: How many Bits were in the code for Test #1: “BABAB?” (5)

Objective: Today you and your partner will be developing a protocol for exchanging 2-bit messages using an Internet Simulator.
Today we will be using an Internet Simulator to explore some of the challenges of sending bits on the Internet. This tool simulates a single wire connecting two people who cannot otherwise see or speak to each other. The Internet Simulator helps to enforce “the binary rule” for sending messages – it will present challenges that you will need to problem solve around.

Accessing the Internet Simulator:

• Go to the CSP Class Web Page and click on the Link to Code.org Student
• Accounts:   http://studio.code.org/sections/WGYXCF
• Click on your name and image and sign in.
• Select stage 3 and click on: Internet Simulator: Sending Binary Messages
• Select ok
• Then select your partner from the class list.

Ok students, time to dive in and see if you can figure out how to use the Internet Simulator. Have Fun!
Internet Simulator Tool Tutorial

At the moment you and your partner decide you would like a little guidance, view the following video so that you can see how others came to successfully use the simulator. Remember…it is all about Timing & Synchronization! You need to write your own rules or protocols to make it work.
An example of how the Internet Simulator is being used.

Journal: How did you and your partner rewrite your protocol to have a more successful discussion on the Internet Simulator. (With Partner!)