Knights of Bots: October 2017

Oops, we did it again! A Knights of Bots has finished building an EV3 butler bot. Equipped with a tray and cup holder, its main purpose is to deliver items such as drinks and food. Butler bot is remote controlled.

Here is a picture and video of the robot:

Multiple Pics of different angles of robot here

This robot is made of:

1 EV3 Brick

1 Ultrasonic Sensor

1 IR Sensor

4 Large Motors

1 EV3 Infrared Beacon (remote)

ROBOT SPECS

At first, medium motors were used to lift the tray up and down. Unfortunately, the medium motors were not strong enough to lift the tray so the motors were switched to large motors. These large motors are connected to the rack gear system that lifts the tray.

A 40 tooth gear, 8 tooth gear, and 24 tooth clutch gear are used in this gearing system (shown below).

The tray caused butler bot to fall over. To fix this problem, a wheel was added to balance out the robot. The wheel is attached to a white beam. This beam itself is independent of the robot. The beam is placed inside a box made of other beams that is connected to the robot. When the tray lifts, the white beam and the wheel stay on the ground but the box lifts. This mechanism allows for the tray to lift while the robot maintains its balance.

PROGRAM

The entire program is placed within an unlimited loop block. Inside the loop is a switch block. The switch block is set to Ultrasonic Sensor, Compare Type 4, Distance 20 Centimeters. If the ultrasonic sensor senses an object that is less than 20 centimeters away, the program in the true section (this section is marked by a check mark) of the switch block will run. This program tells the robot to say "Object Detected", move back 1 rotation, and allow the person using the remote control to direct the robot away from the object. This program function prevents the robot from crashing into objects and allows it to be controlled from another room.

However, if the ultrasonic sensor does not sense an object 20 cm away, it will run the program in the false section. This program consists of a mini block titled "Remote_Buttons". The mini block program contains the instructions for Butler Bot to be remote controlled. It assigns each button of the remote a different function. Press both of the top buttons to move forward. Two of the bottom buttons to move backward. Top left to turn left, top right to turn right, bottom left to lift the tray up, bottom right to lower the tray, press no buttons to stop the robot.