Lego Robotics: engineering and science made fun!!!

Lego Robotics and More

Saturday, January 14, 2006

Things That are Important on a Robot

1. Swivel - This is put on the front of your robot and enables your robot to turn.

2. Robot Arms and Claws - These are connected to a third motor and are used to move things and to lift things up.

3. Gear Trains - You use these to control your robot's speed and to power it up and power it down.

4. Sensors - These have mixed jobs and are essential for performing many tasks with ease.


The different sensors that you can include on your robot are the touch sensor, light sensor, and the rotation sensor. The touch sensor can be used to make the robot perform an action after it is pushed in a certain amount of times. So you can tell your robot to keep moving until a touch sensor is hit and then to reverse for two seconds or whatever else you need it to do. A light sensor can be used to make your robot stop when it spots a light color or to perform a function like moving a robot arm when it spots a darker color. Using a rotation sensor you can see the number of rotations it takes your robot to travel a certain distance and you will be able to put this into your program to make your robot's movements more accurate and not put so much work on yourself as if you were using a timer. When you use timers you have to guess the amount of time it takes for your robot to go a certain distance and you have to keep adjusting it but by using the rotation sensor you will almost always get it on the first try or if you are off by a little a couple of more times. As you can see the use of sensors is very beneficial.

Friday, January 13, 2006

Gears and Geartrains

In Lego Robotics class our teacher Mr. Wright taught us about adding gears and creating gear chains on our robots. He told us that lego gears had multiples of eight for the amounts of teeth on them. This can help greatly becuse it is easier to create ratios stating the relationship of the number of spins of the gearswhen we create gear trains. If you put a sixteen-tooth onto the motor and connect it to an eight-tooth gear with an axel and wheels attached to it the wheels will turn twice for every one time the motor spins once. That example sped up the robot but if you switched the two gears around the wheels would turn once for everytime the motor spins twice. In these examples the ratios of the spins of the motor-gear to the wheel-gears where 1:2 in the faster gear chain and 2:1 on the slower gear train. When a robot moves slower it has more strength but if it moves faster it has less strength. Also, the size of the wheels that you use afects speed. A larger wheel will travel faster than a smaller wheel so you can use gears to alter this slightly or greatly. Make sure that you do not make your robot too fast or it will be so weak it will tear itself apart near the motors but if it's too slow it isn't so reliable either.