Carpet Rover Projects

Contents: 
LED Control | Sound Control | Switch Input | Servo Control | Motion Control
Rover / Bumpers | Rover / IRPD / Bumpers | Line Follower | Photovore

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Make sure that jumpers J-A and J-B are installed for these experiments.

Download Program

Make sure that the piezo speaker is wired directly from Pin 7 and GND for these experiments. Simply cut off the small plug and install the connectors as illustrated in this image. There is no need to install any other components for this to work, however, the quality of the sound will improve if you install a small filter cap across the speaker.

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Make sure that jumpers J-C and J-D are installed for these experiments. Leave the LED jumpers J-A and J-B on as well.

Download Program

In order to control the speed and direction of a modified servo, you first need to calibrate the servos. This is done by sending 1.5mS pulses using the program linked above, and adjusting the potentiometer that comes out of the servo housing until the servo stops rotating. After the servo is calibrated, the speed and direction can be controlled. Adding to the 1.5mS value results in clockwise rotation on the right servo. Subtracting from it results in counter clockwise rotation. The farther the value is from the 1.5mS reference, the faster the servo rotates. The legal range is 1.0mS to 2.0mS. Exceeding these limits will not increase the speed of the servo.

Run the above program to calibrate the servos. Be sure to support the robot off the table so the wheels do not touch it. When you run the program both servos will probably be turning. Start by adjusting one of the potentiometers and notice the speed and direction change. Very slowly adjust it until the servo stops rotating. It will be very touchy, and it might be necessary to add a drop of thread lock or equivalent so the pot won't get bumped out of adjustment.

Program Note: value * 5 = pulse expressed in 2uS units. For example, a value of 150 equals 150 x 5 = 750, 750 x .000002 = .0015 or 1.5mS. This method of servo control pulse generation is used throughout this manual. It allows controlling the servos with a byte variable instead of a word variable.