Second Generation Schematic

The first generation of the Midnight Prowlerbot used bluetooth as a means of communication directly with the Atom Bot Board (and Basic Atom Pro), while the CMUCam2+ also communicated with the Basic Atom Pro. Polling bluetooth and the CMUCam2+ slowed down robot response more than I was willing to tolerate. By the way, the CMUCam2+ would work with the Basic Atom or Basic Atom Pro at a max of 38400 baud (I38400) with the CMUCam2+ using a delay (DM 10) - no settings worked without the delay and the hardware serial port did not work.

The resulting frustration turned the robot into the schematic shown above where two Atom Bot Boards are used to basically do multithreading. The one board handled motion while the other board handled sensors and video. The two ABB boards communicated with each other using serial but with a notifier input to allow programs to avoid even checking for serial input until it was actually available.

However, a drawback of this configuration is that using the video functions requires too much experimentation during programming since it isn't possible to actually see what the camera is seeing while programming.

Midnight Prowlerbot Control Description

The screenshot displays the main screen for the Midnight ProwlerBot Control program. Each of the buttons shown perform the same function as the corresponding buttons on the PS2 controller.

The Joysticks section simulates joystick action by using slidebars. The slidebars maintain their position so that the robot can be set walking in a direction without being held as would be done with a joystick. Since it can be difficult to slide all of the bars back to zero position quickly in the event that the robot is about to collide with something, a Stop button is provided that acts as an emergency stop for the robot.

The sensors section displays the direction that the robot is facing in degrees. For instance, it may display W=270, which would mean that the robot is facing west which is also 270 degrees.

Distances to objects are displayed in centimeters with the topmost object displaying the distance sensed by the ultrasonic sensor and the infrared sensor distance displayed below. Two types of sensors are used primarily because of expense. Ultrasonic sensors cost at least twice the price of a Sharp GP2D12 IR sensor.

The ultrasonic sensor is used for obstacle checking directly in front of the robot while IR sensors are used on either side of the robot. Currently, only one IR sensor is installed on the robot but a second IR sensor will soon be installed. By using IR sensors on the sides at approximately a 30 degree angle from center, it is possible to make sure that the robot can walk through an opening without interference. By using the ultrasonic sensor on the front, it is possible to look for obstacles or objects at longer distance than with inexpensive IR sensors.

WinCVS was used for version control and change tracking for both the Midnight ProwlerBot VB.Net program and the Basic Atom Pro code in the robot.