BitBot Package for Microsoft PXT

Based off initial work by Sten Roger Sandvik, updated/expanded by Gareth Davies and Andrew Mulholland.

This library provides a Microsoft PXT package for BitBot and BitBot XL, see https://4tronix.co.uk/bitbot/.

Selecting the Model of BitBot

You can now use either a classic BitBot or a BitBot XL. The pins used for motors and sensors are different so it is necessary to select the correct model. You can force the selection using:

bitbot.select_model(BBModel.Auto)  // this will force the BitBot to re-select the correct model
bitbot.select_model(BBModel.Classic)
bitbot.select_model(BBModel.XL)

Or you can leave the BitBot to automatically decide and not use this command at all. It will do this at the start of the program so it requires the BitBot to be switched on to make the correct selection. If you do it automatically then you can use the same hex code for both models. You can check what model is being used by:

bitbot.getModel()

Driving the robot

The simplest way to drive robot is by using the driveMilliseconds(...) and driveTurnMilliseconds(...) blocks.
Note with driveMilliseconds(...), you can specify a negative speed to reverse.

// Drive forward for 2000 ms
bitbot.driveMilliseconds(1023, 2000)

// Drive backwards for 2000 ms
bitbot.driveMilliseconds(-1023, 2000)

// Turn left for 200 ms
bitbot.driveTurnMilliseconds(BBRobotDirection.Left, 1023, 200)

// Turn right for 200 ms
bitbot.driveTurnMilliseconds(BBRobotDirection.Right, 1023, 200)

These blocks are also available in non blocking version. The following example performs the same operation as above.

bitbot.drive(1023)
basic.pause(1000)

bitbot.drive(0)
basic.pause(1000)

bitbot.driveTurn(BBRobotDirection.Left, 1023)
basic.pause(250)

bitbot.driveTurn(BBRobotDirection.Right, 1023)
basic.pause(250)

bitbot.drive(0)

Stopping

When the motor speed is set to zero then it stops. However, we can also use the motor itself to create a reverse generated current to brake much quicker. This helps when aiming for more accurate manoeuvres. Use the bitbot.stop(...) command to stop with braking, or coast to a halt

bitbot.robot_stop(BBStopMode.Coast) # slowly coast to a stop
bitbot.robot_stop(BBStopMode.Brake) # rapidly brake

Driving the motor

If you want more fine grain control of individal motors, use bitbot.motor(..) to drive motor either forward or reverse. The value indicates speed and is between -1023 to 1023. Minus indicates reverse.

// Drive 1000 ms forward
bitbot.motor(BBMotor.All, 1023);
basic.pause(1000);

// Drive 1000 ms reverse
bitbot.motor(BBMotor.All, -1023);
basic.pause(1000);

// Drive 1000 ms forward on left and reverse on right
bitbot.motor(BBMotor.Left, 1023);
bitbot.motor(BBMotor.Right, -1023);
basic.pause(1000);

Buzz sound

To use the buzzer, just use bitbot.buzz(..) function with either 1 (sound) or 0 (no-sound).

// Buzz for 100 ms
bitbot.buzz(1);
basic.pause(100);
bitbot.buzz(0);

Read line sensor

The BitBot has two line-sensors: left and right. To read the value of the sensors, use bitbot.readLine(..) function.

// Read left and right line sensor
let left = bitbot.readLine(BBLineSensor.Left);
let right = bitbot.readLine(BBLineSensor.Right);

Read light sensor

Light sensors can be read using bitbot.readLight(..) function.

// Read left and right light sensor
let left = bitbot.readLight(BBLightSensor.Left);
let right = bitbot.readLight(BBLightSensor.Right);

Read sonar value

If you have mounted the optional sonar sensor for the BitBot you can also use the bitbot.sonar(..) function to read the distance to obstacles.

// Read sonar values
let v1 = bitbot.sonar(BBPingUnit.MicroSeconds);
let v2 = bitbot.sonar(BBPingUnit.Centimeters);
let v3 = bitbot.sonar(BBPingUnit.Inches);

NeoPixel helpers

The BitBot has 12 NeoPixels mounted. This library defines some helpers for using the NeoPixels.

// Show all leds
bitbot.neoSetColor(neopixel.colors(NeoPixelColors.Red));
bitbot.neoShow();

// Clear all leds
bitbot.neoClear();
bitbot.neoShow();

// Show led at position 1
bitbot.neoSetPixelColor(0, neopixel.colors(NeoPixelColors.Red));
bitbot.neoShow();

// Show led rainbow
bitbot.neoRainbow();
bitbot.neoShow();

// Show led rainbow and shift
bitbot.neoRainbow();
bitbot.neoShift();
bitbot.neoShow();

// Show led rainbow and rotate
bitbot.neoRainbow();
bitbot.neoRotate();
bitbot.neoShow();

// Set brightness of leds
bitbot.neoBrightness(100);
bitbot.neoShow();

// Use neo() variable
bitbot.neo().clear();
bitbot.neo().show();

Supported targets

• for PXT/microbit

License

MIT