RFG Week 2

Today I wanted to demonstrate the combined use of a sensor and a motor.  So this morning, before the class, I connected a sound sensor to one of the robots and downloaded a little program.  The little program didn't work properly.  I put the sensor on a different port with no effect.  I replaced the sensor with no effect.  I replaced the sensor cable with no effect.  Then I replaced the NXT block, and it worked.  The visible effect of the problem was that the reading from the sensor was erratic.  Using VIEW, the sensor output seemed OK, but when I monitored the sensor output in the monitor window, it was erratic.  Hmm.  I replaced the batteries, hoping that would solve the problem.  No such luck.  So, during the class I let one team use the defective NXT block for the first part of the lab and then watch the other teams for the second part of the lab. 

Some good questions came from the lab - nobody was asleep for very long, I guess.  One student asked how to upload programs from the NXT block.  I knew it was possible, but didn't know how to do it.

Next week I will try to borrow another robot from the Encino Park Robo Club.

This is the robot configuration used for this week's class.  The sensor on the robot's left side is a sound sensor.

Technical problem

The robot loaned by Encino Park Elementary's robotics club did something strange when I ran the little demo program to test it. It veered away from a straight line. It will take some more testing to determine whether the problem is in one of the servos or in a wheel or in the caster at the back. I will check the caster at the back first, by aligning it in a trailing position first, then in a leading position, then in a cross-path position. Each of those should produce a characteristic behavior. If that isn't the problem, I will check the tires. If one of them is mis-mounted on its wheel, I think that could cause the off-track behavior. If that isn't the problem, I will check the motors.

After checking again, I found no problems. Maybe a glitch, I don't know. Not to worry.