PmWiki | Student / Lab1WriteUpEw

Question 1

Purpose:
How Quickly are consecutive commands executed by the Create OI?
Hypothesis:

I believe the create will react almost instantaneously, from the moment it recieves a series of commands to the moment it executes them. I belive the time will not be easily measurable and

Experiment:

Materials:
Experiment 1
* create robot
* real-term
* serial port
* serial cable
Experiment 2
*serial cable

computer
create robot
stop watch
serial port

Procedure:

I plan on focusing on the LEDS, by lighting up the power button first, followed by the play button, and lastly by the advance button. By putting these on repeat with a script command, it should create a ripple effect, which I can then use to find the time it takes between the receive and execution time of the robot. If it is too fast for me to count, I will have to use an alternate procedure to measure the times.

Data:
-> Using the script: 152,13,139,0,255,255,139,8,0,0,139,2,0,0,153

I made the LEDs light up one after the other, from left to right, following a ripple like pattern. The lights were lighting up so quickly, that the human eye could not detect the change, the LEDS only appeared to be slightly flickering. So I decided to use another experiment to find an accurate time between each consecutive command.\\

In my next experiment I decided to take a script with several actions in it, and make sure it ends with a beep. This way I can count how long it is between each beep, and divide by "x" amount of actions. So I used the script: 128 131 140 1 4 77 50 152 10 139 08 0 0 139 0 255 255 141 1 153, this made the play and advance LEDs turn on, and then when they turn off, the power button will go on, and then there will be a beep.\\

Results: trial 1: .14 secs trial 2: .09 trial 3: .12

Conclusion

As my hypothesis suggests, I have concluded that the create reacts almost instantaneoulsy, from the moment it recieves it commands until the execution. The LEDs and the sounds proved to be the most accurate way of measuring the amount of time between commands, because drive scripts require the use of motors, which can effect your data, since they have to warm up and react, resulting in a certain percentage of error. The lights also need to take the actions of "lighting up" and "cooling off", however, those actions happen relatively faster than the reactions of the robot's motors, and when we are using such minute times, we need to be as accurate as possible. The only really effective way to get the robot to delay is to use a wait command in your script, for this allows you to control how much time is "waited" between each command.

An example of a simple script, that allows control of the delays is:

152, 10, 139, 8, 0, 0, 155, 50, 139, 8, 255, 255, 153

This script turns on the play and advance light (power light is off), and then it delays for five seconds before it executes its second command, which is to turn all three lights on.