Motor

Motor example

Program

public class MotorsExample {

    public static void main(String[] args) {
        Tools.log("---- Motors Example ----");
        BrickPi.MA = new Motor();
        int range = 500;
        BrickPi.MA.onChange(range, evt -> Tools.log("Encoder value updated (with a delta >= " + range + "): " + evt.getNewValue()));
        BrickPi.MA.onRotate( evt -> Tools.log("Rotate"));
        BrickPi.start();
        Tools.log("Encoders " + BrickPi.MA.getEncoderValue());
        BrickPi.MA.setPower(100);
        Tools.sleepMilliseconds(10000);
        
        BrickPi.MA.stop();
        BrickPi.MA.resetEncoderValue();
        
        Tools.log("Encoders " + BrickPi.MA.getEncoderValue());
        BrickPi.MA.setPower(100);
        Tools.sleepMilliseconds(10000);
        Tools.log("stop");
        BrickPi.stop();
    }
}

Sensors

public class TouchSensorExample {

    public static void main(String[] args) {
        Tools.log("---- Touch Sensor Example ----");
        BrickPi.S1 = new TouchSensor();
        
        BrickPi.S1.onChange((ValueChangeEvent evt) 
                -> Tools.log("State changed: old value=" + evt.getOldValue() 
                + " new value=" + evt.getNewValue()));
        
        BrickPi.start();
        Tools.sleepMilliseconds(10000);
        BrickPi.stop();
        
    }

}

public class LightOnSensorExample {

    public static void main(String[] args) {
        Tools.log("---- Light Sensor On Example ----");
        BrickPi.S1 = new LightOnSensor();

        int range = 50;
        BrickPi.S1.onChange(range, (ValueChangeEvent evt) 
                -> Tools.log("Light intensity updated (with a delta > " + range 
                        + "): old value=" + evt.getOldValue() + " new value=" + evt.getNewValue()));
        
        BrickPi.start();
        Tools.sleepMilliseconds(10000);
        BrickPi.stop();
    }
}

public class LightOffSensorExample {
    
    public static void main(String[] args) {
        Tools.log("---- Light Off Sensor Example ----");
        BrickPi.S1 = new LightOffSensor();
        
        int range = 50;
        BrickPi.S1.onChange(range, (ValueChangeEvent evt) 
                -> Tools.log("Light intensity updated (with a delta > " + range 
                        + "): old value=" + evt.getOldValue() + " new value=" + evt.getNewValue()));

        BrickPi.start();
        Tools.sleepMilliseconds(10000);
        BrickPi.stop();
    }

public class UltraSonicSensorExample {
    
    public static void main(String[] args) {
        Tools.log("---- Ultra Sonic Sensor Example ----");
        BrickPi.S1 = new UltraSonicSensor();
        
        int range = 20;
        BrickPi.S1.onChange(range, (ValueChangeEvent evt) 
                -> Tools.log("Distance updated (with a delta > " + range 
                        + "): old value=" + evt.getOldValue() + " new value=" + evt.getNewValue()));
        
        BrickPi.start();        
        Tools.sleepMilliseconds(10000);
        BrickPi.stop();
    }
}

public class SoundSensorExample {
    
    public static void main(String[] args) {
        Tools.log("---- Sound Sensor Example ----");
        BrickPi.S1 = new SoundSensor();
        
        int range = 60;
        BrickPi.S1.onChange(range, evt -> Tools.log("##Sound sensor value updated (with a delta > " + range 
                        + "): old value=" + evt.getOldValue() + " new value=" + evt.getNewValue())
                );
        
        BrickPi.start();
        Tools.sleepMilliseconds(10000);
        Tools.log("Stop");
        BrickPi.stop();
    }
}

LEDs

Program

public static void main(String[] args) {
        Tools.log("---- Leds Blink Example ----");
        BrickPi.LED1.on();
        BrickPi.LED2.off();
        for(int i = 0; i < 42; i++) {
            BrickPi.LED1.toggle();
            BrickPi.LED2.toggle();
            Tools.sleepMilliseconds(100);
        }
        BrickPi.LED1.off();
        BrickPi.LED2.off();
    }

HC-SR04 Ultrasonic

Example

Circuit

Ultrasonic sensor (HC-SR04) - Circuit.

Program

public static void main(String[] args) {
    UltrasonicHCSR04 ultrasonicSensor = new UltrasonicHCSR04(GPIOPin.GPIO_00, GPIOPin.GPIO_02);

    while(true) {
        Tools.log(ultrasonicSensor.getDistance() + "cm");
        Tools.sleepMilliseconds(300);
    }
}

MPU6050 Gyroscope & Accelerometer

Visualizers

Live charts

We provide you with a built-in visualizer that you can easily use, right from this website. The aim of this visualizer is to show data retrieved from an accelerometer, a gyroscope or a complementary filter (this is not limited to the MPU6050 case).

To use this visualizer, you simply need to launch a server like the one presented in raspoid/src/main/com/raspoid/examples/network/MPU6050Accelerometer.java.

This visualizer uses your local network to communicate with your robot. It is then required to use an extension like CORS (Chrome or Firefox) to enable cross-origin resource sharing.

You can get the code of this visualizer here: visualizer.html (bootstrap.min.css and jquery-1.12.0.min.js required).

3D visualizer

This 3D python visualizer uses OpenGL and is based on the work of Andrew Birkett, presented in a post on Bitify (16 November 2013).

Our adapted code is available here: 3DVisualizer.py.

Example

Circuit

Gyroscope & Accelerometer (MPU6050) - Circuit.

Program

public static void main(String[] args) {
    MPU6050 mpu6050 = new MPU6050();
    
    while(true) {
        Tools.log("-----------------------------------------------------");
        
        // Accelerometer angles
        Tools.log("Accelerometer:");
        double[] accelAngles = mpu6050.getAccelAngles();
        Tools.log("\t" + xyzValuesToString(angleToString(accelAngles[0]), 
                angleToString(accelAngles[1]), angleToString(accelAngles[2])));
        
        double[] accelAccelerations = mpu6050.getAccelAccelerations();
        Tools.log("\tAccelerations: " + xyzValuesToString(accelToString(accelAccelerations[0]), 
                accelToString(accelAccelerations[1]), accelToString(accelAccelerations[2])));
        
        // Gyroscope angles
        Tools.log("Gyroscope:");
        double[] gyroAngles = mpu6050.getGyroAngles();
        Tools.log("\t" + xyzValuesToString(angleToString(gyroAngles[0]), 
                angleToString(gyroAngles[1]), angleToString(gyroAngles[2])));
        
        double[] gyroAngularSpeeds = mpu6050.getGyroAngularSpeeds();
        Tools.log("\t" + xyzValuesToString(angularSpeedToString(gyroAngularSpeeds[0]),
                angularSpeedToString(gyroAngularSpeeds[1]), angularSpeedToString(gyroAngularSpeeds[2])));
        
        // Filtered angles
        Tools.log("Filtered angles:");
        double[] filteredAngles = mpu6050.getFilteredAngles();
        Tools.log("\t" + xyzValuesToString(angleToString(filteredAngles[0]), 
                angleToString(filteredAngles[1]), angleToString(filteredAngles[2])));
        
        Tools.sleepMilliseconds(5);
    }
}

Servomotor

Example

Circuit

Servomotor (TowerPro MG90S) - Circuit.

Program

public static void main(String[] args) {
    ServoMotor motor;
    
    // Using a PWM pin
    motor = new TowerProMG90S(PWMPin.PWM1);
    
    // Using a PCA9685
    //motor = new TowerProMG90S(new PCA9685(), PCA9685Channel.CHANNEL_01);
    
    double[] angles = {0, 45, 90, 135, 180, 135, 90, 45, 0};
    
    for(int i = 0; i < angles.length; i++) {
        motor.setAngle(angles[i]);
        Tools.log("position angle: " + motor.getPositionAngle());
        Tools.sleepMilliseconds(1500);
    }
}

Photoresistor

Example

Circuit

Photoresistor - Circuit.

Program

public static void main(String[] args) {
    Photoresistor photoresistor = new Photoresistor(new PCF8591(), PCF8591InputChannel.CHANNEL_0);

    while(true) {
        Tools.log(photoresistor.getIntensity());
        Tools.sleepMilliseconds(250);
    }
}

LED & LED PWM

A LED is a Light-Emitting Diode. This is a semiconductor that turns electric energy into light energy via a PN junction. Depending on the specifications of the LED, the wavelength of the emitted light can be of any value such as infrared, visible (red, orange, yellow, green, blue, violet), or other.

It is important to not exceed the maximum current allowed through a LED (typically from 10 to 30mA for a basic low power LED) to not destroy it. It is also important to respect the polarity of the diode: we connect the "-" pole to the cathode "-" and therefore the "+" pole to the anode "+".

Example LEDs

In this first example, we use four LEDs of different colors. Each LED is controlled from the Raspberry Pi with the GPIO pins, as presented in the code listing.

Circuit

LED - Circuit.

Program

public static void main(String[] args) {
    LED white = new LED(GPIOPin.GPIO_26);
    LED green = new LED(GPIOPin.GPIO_27);
    LED red = new LED(GPIOPin.GPIO_28);
    LED yellow = new LED(GPIOPin.GPIO_29);

    while (true) {
        white.toggle();
        Tools.sleepMilliseconds(250);
        green.toggle();
        Tools.sleepMilliseconds(250);
        red.toggle();
        Tools.sleepMilliseconds(250);
        yellow.toggle();
        Tools.sleepMilliseconds(250);
    }
}

Example PWM LED

A PWM LED refers to a LED controlled with a PWM signal. With a PWM signal, it is possible to control the energy sent to the LED, and therefore the brightness intensity of the LED.

In this second example, a LED is controlled with a PWM signal, generated from a PCA9685 board. The PCA9685 is controlled from the Raspberry Pi with the I²C protocol. In the code listing, the LED blinks with a dimmer effect.

Circuit

LED PWM - Circuit.

Program

public static void main(String[] args) {
    LEDPWM led = new LEDPWM(new PCA9685(), PCA9685Channel.CHANNEL_00);
    
    while(true) {
        for(int i=0; i<100; i++) {
            led.setIntensity(i);
            Tools.sleepMilliseconds(5);
        }
        
        for(int i = 100; i > 0; i--) {
            led.setIntensity(i);
            Tools.sleepMilliseconds(5);
        }
    }
}

Button & Touch switch

A button is a switch which lets the current flow or not. It can be in a direct (the current flows when the button is pressed) or reverse mode (the current flows when the button is released).

A touch switch is a button which state is toggled at each finger touch. First touch: the signal goes high; second touch: the signal goes down; and so on.

Example

In this example, a simple button is connected to the Raspberry Pi. When the button is pressed, an interruption is detected by the Raspberry Pi, and an event is retrieved by the Raspoid program, as presented in the code listing. The same process happens when the button is released.

Circuit

Example of a simple button connected to a GPIO pin. Black: ground; Violet: GPIO 0.

Program

public static void main(String[] args) {
    Button button = new Button(GPIOPin.GPIO_00);
    
    // Add a listener for button pressed/released events
    button.getGpioPinDigitalInput().addListener((GpioPinListenerDigital)
            (GpioPinDigitalStateChangeEvent event) -> Tools.log(button.isPressed() ? "button pressed" : "button released"));
    
    Tools.sleepMilliseconds(15000);
}

LCD Display - LCM1602

The LCM1602 is an LCD display of 2 lines and 16 columns (it can display 32 ASCII characters), that can directly be used with the I²C protocol. We implemented a complete wrapper for this component in the Raspoid framework so that it can easily be used.

Example

In this example, the LCD1602 is connected to the LCM1602 (generally, the two components are already welded when purchased). The LCM1602 is connected to the ground, to the 5v power, and to the SDA and SCL pins of the Raspberry Pi.

As presented in the code listing, the LCD displays the current time in the "HH:mm:ss" format, and updates it 4 times per second to avoid delays between the displaying and real time.

Circuit

Example of use of an LCM1602 - Circuit.

Program

public static void main(String[] args) {
    LCM1602 display = new LCM1602();
    display.setDisplay(true, false, false);

    // To execute on exit (clean screen)
    Runtime.getRuntime().addShutdownHook(new Thread(() ->
            display.disableDisplay()));

    display.writeText(0, 0, "Raspoid  Welcome");
    
    SimpleDateFormat formatter = new SimpleDateFormat("HH:mm:ss");
    while (true) {
        display.writeText(4, 1, formatter.format(new Date()));
        Tools.sleepMilliseconds(250);
    }
}

Joystick

A joystick is mainly composed of two analog outputs. The intensity of the output signal is directly related to the position of the joystick, in the x and y axis (the two analog outputs). From the ADC, we can then retrieve (x,y) coordinates with x and y varying in a range from 0 to 255: (0,0)=bottom left; (126,126)=default position; (255,255)=top right; etc.

The joystick we experimented with with here is an "analog" joystick very similar to those on PlayStation 2 controllers. Positions in x and y are translated from potentiometers (one for each axis). This kind of joystick also acts has a press button. When the button is pressed, the corresponding pin is linked to the ground, and an interruption can be detected.

Example

In this example, a joystick is connected to a PCF8591 (ADC). This ADC is connected to the Raspberry Pi and the I²C protocol is used to retrieve digital values converted from the joystick, and stored on the registers of the PCF8591.

Circuit

Example of use of a joystick - Circuit.

Program

public static void main(String[] args) {
    Joystick joystick = new Joystick(new PCF8591(), PCF8591InputChannel.CHANNEL_0, PCF8591InputChannel.CHANNEL_1, PCF8591InputChannel.CHANNEL_2);
    
    while(true) {
        Tools.log(joystick.getPosition()); // press-down, up/down, left/right, home
        Tools.sleepMilliseconds(250);
    }
}

Rotary Encoder

A rotary encoder is used here to detect the orientation of a shaft. Two digital input pins are used by this module. The signals on those two pins are analyzed and combined to deduce the direction of new rotations. We then use a counter to represent the orientation: when turned to the right, the counter is incremented; when turned to the left, it is decremented.

Example

In the following example, a rotary encoder is connected to the Raspberry Pi by using three GPIO pins. Digital values read from those pins are combined to determine the direction of new rotations. Internally, a counter is used to represent the position of the shaft of the rotary encoder. When turning to the right or to the left, the updated value of the counter will be printed in the standard output.

Circuit

Example of use of a rotary encoder - Circuit.

Program

public static void main(String[] args) {
    RotaryEncoder rotaryEncoder = new RotaryEncoder(GPIOPin.GPIO_27, GPIOPin.GPIO_28, GPIOPin.GPIO_29);
    
    rotaryEncoder.getGpioPinDigitalInput().addListener((GpioPinListenerDigital)
            (GpioPinDigitalStateChangeEvent event) -> Tools.log(rotaryEncoder.isPressed() ? "rotary pressed" : "rotary released"));
    
    int previousCounterValue = rotaryEncoder.getCounterValue();
    while(true) {
        rotaryEncoder.getEncoderTurn();
        if(previousCounterValue != rotaryEncoder.getCounterValue()) {
            Tools.log(rotaryEncoder.getCounterValue());
            previousCounterValue = rotaryEncoder.getCounterValue();
        }
    }
}

Temperature

A thermistor is made of semiconductor materials, for which the resistance varies significantly with ambient temperature. It can mainly be used to detect variations of the ambient temperature.

Example

In this example, a thermistor is connected to a PCF8591 (ADC). This ADC is connected to the Raspberry Pi and the I²C protocol is used to read values converted from the thermistor and stored in the registers of the PCF8591.

Circuit

Example of use of thermistor - Circuit.

Program

public static void main(String[] args) {
    Thermistor thermistor = new ThermistorNTCLE203E3103SB0(new PCF8591(), PCF8591InputChannel.CHANNEL_0);
    
    while(true) {
        Tools.log(thermistor.getTemperature());
        Tools.sleepMilliseconds(500);
    }
}

BMP180 Barometer

The barometer BMP180 is a digital barometric pressure sensor. It can be used to measure air pressure and temperature. The pressure varying with the altitude, this sensor can also be used as an altimeter.

Example

In this example, a BMP180 is connected to the Raspberry Pi and the I²C protocol is used to communicate with the sensor and retrieve data from the registers of the component.

Circuit

Example of use of a BMP180 - Circuit.

Program

public static void main(String[] args) {
    BarometerBMP180 barometer = new BarometerBMP180();
    
    while(true) {
        Tools.log(
            "Air pressure: " + barometer.readUncompensatedPressure() + " " +
            "True air pressure: " + barometer.calculateTruePressure() + " Pa\n" +
            "Temperature: " + barometer.readUncompensatedTemperature() + " " +
            "True temperature: " + barometer.calculateTrueTemperature() + "°C\n" +
            "Altitude: " + barometer.calculateAbsoluteAltitude() + "m",
            Tools.Color.ANSI_GREEN);
        Tools.sleepMilliseconds(1000);
    }
}

IR Receiver

Our implementation of the infrared transmitter/receiver allows the user to easily control its robot with infrared signals.

The infrared receiver has been designed here to detect infrared signals sent from a media remote (for instance). The implementation of an infrared media remote using an infrared-LED can be made with the IR transmitter previously presented.

Example

In the first part of this example, when an infrared signal is detected by the IR receiver, if the signal is correctly decoded, the result is printed in the standard output.

In the second part of this example, an infrared signal is sent through the infrared LED. This signal is the same as the signal sent from the infrared media remote sold by Sunfounder, when button 1 is pressed.

Circuit

Example of use of an IR receiver (on the left) and an IR transmitter (on the right) - Circuit.

Program

public static void main(String[] args) {
    IRReceiverOS1838B irReceiver = new IRReceiverOS1838B(GPIOPin.GPIO_00);
    
    while(true) {
        IRSignal newSignal = irReceiver.detectSignal();
        
        IRSignal signalDecoded = irReceiver.decodeIRSignal(new IRProtocolSunfounderMediaRemote(), newSignal);
        if(signalDecoded != null)
            Tools.log("New signal received and decoded: " + signalDecoded.getName());
        else
            Tools.log("New signal received but NOT decoded: " + newSignal);
    }
}

IR Transmitter

Our implementation of the infrared transmitter/receiver allows the user to easily control its robot with infrared signals.

An infrared transmitter is an infrared LED that should be connected to a Raspberry Pi's PWM pin (the frequency from the PCA9685 is not enough for infrared signals). Infrared signals can then be sent and detected with the receiver presented here after.

Example

In the first part of this example, when an infrared signal is detected by the IR receiver, if the signal is correctly decoded, the result is printed in the standard output.

In the second part of this example, an infrared signal is sent through the infrared LED. This signal is the same as the signal sent from the infrared media remote sold by Sunfounder, when button 1 is pressed.

Circuit

Example of use of an IR receiver (on the left) and an IR transmitter (on the right) - Circuit.

Program

public static void main(String[] args) {        
    IRTransmitter transmitter = new IRTransmitter(PWMPin.PWM0);
    transmitter.transmitSignal(IRProtocolSunfounderMediaRemote.button1);
    Tools.log("IR signal sent");
}

Accelerometer - ADXL345

The accelerometer ADXL345 is a cheap accelerometer that can be used to retrieve accelerations for x, y and z axes.

Example

In this example, we use the I²C protocol to control the accelerometer, and to retrieve values corresponding to (x, y, z) coordinates of the last measured acceleration vector.

Circuit

Example of use of an ADXL345 accelerometer - Circuit.

Program

public static void main(String[] args) {
    AccelerometerADXL345 accel = new AccelerometerADXL345();
    
    while(true) {
        Tools.log("Acceleration: " + accel.getGAcceleration()); // {x, y, z} vector
        Tools.log("Pitch angle: " + accel.getPitchAngle() + "°");
        Tools.sleepMilliseconds(250);
    }
}

LM386 Sound

A sound sensor is composed of a simple microphone and is able to detect ambient sound intensity by converting audio signals to analog electrical signals.

Example

In this example, the sound sensor is used with a PCF8591 to convert the analog signal to a digital one. The PCF8591 is connected to the Raspberry Pi and the I²C protocol is used to retrieve those digital values.

Circuit

Example of use of a sound sensor - Circuit.

Program

public static void main(String[] args) {
    SoundSensor soundSensor = new SoundSensor(new PCF8591(), PCF8591InputChannel.CHANNEL_0);
    
    while(true) {
        Tools.log(soundSensor.getIntensity());
        Tools.sleepMilliseconds(25);
    }
}

Active Buzzer

An active buzzer has a built-in oscillating source. It will produce a sound at a specific frequency, as long as it is electrified.

Example

In this example, we show the use of a buzzer. This buzzer can be active or passive. The only difference in the circuit is the pin used on the Raspberry Pi. This pin must be a PWM pin for a passive buzzer (to play specific tones by adapting frequencies of the PWM signal), while it must be a classical GPIO pin for an active buzzer (it produces sound only when electrified).

In this example, the active buzzer will loop between beep and silence every 500 milliseconds.

Circuit

Example of use of an active buzzer - Circuit.

Program

public static void main(String[] args) {
    ActiveBuzzer buzzer = new ActiveBuzzer(GPIOPin.GPIO_00, true);
    while(true)
        buzzer.beep(500);
}

Passive Buzzer

A passive buzzer can be used to control the frequency of the generated sounds. Our implementation allows the user to play music by specifying base tones, octaves and notes duration.

Example

In this example, we show the use of a buzzer. This buzzer can be active or passive. The only difference in the circuit is the pin used on the Raspberry Pi. This pin must be a PWM pin for a passive buzzer (to play specific tones by adapting frequencies of the PWM signal), while it must be a classical GPIO pin for an active buzzer (it produces sound only when electrified).

In this example, the passive buzzer will play each note of the scale "do re mi fa sol la si", and loop through octaves from 0 to 7 (500 milliseconds per tone).

Circuit

xample of use of a passive buzzer - Circuit.

Program

public static void main(String[] args) {
    int timePerNote = 500; // ms
    PassiveBuzzer buzzer = new PassiveBuzzer(PWMPin.PWM1);
    
    for(int i=0; i <= 7; i++) {
        buzzer.playNote(BaseNote.DO_0, i, timePerNote);
        buzzer.playNote(BaseNote.RE_0, i, timePerNote);
        buzzer.playNote(BaseNote.MI_0, i, timePerNote);
        buzzer.playNote(BaseNote.FA_0, i, timePerNote);
        buzzer.playNote(BaseNote.SOL_0, i, timePerNote);
        buzzer.playNote(BaseNote.LA_0, i, timePerNote);
        buzzer.playNote(BaseNote.SI_0, i, timePerNote);
    }
}

Tracking Sensor - TCRT5000

A tracking sensor uses the same principle as the infrared obstacle avoidance module. An infrared signal is emitted, and the reflected signal is received by the detector part of the module. The particularity used here, is that black color will not reflect infrared signals. Thus, the sensor can be oriented towards the ground, and used to track a black line.

Example

In this example, when the detected color switches between white and black, an event is triggered and the new detected color is printed in the standard output.

Circuit

Example of use of a tracking sensor - Circuit.

Program

public static void main(String[] args) {
    TrackingSensor trackingSensor = new TrackingSensor(GPIOPin.GPIO_00);
    
    trackingSensor.getGpioPinDigitalInput().addListener((GpioPinListenerDigital)
            (GpioPinDigitalStateChangeEvent event) ->
    Tools.log("Color: " + (event.getState().isLow() ? "white" : "black")));
}

IR Obstacle Avoidance Module

The infrared obstacle avoidance module is a little chip composed of an infrared emitter and an infrared receiver. It uses the infrared reflection principle to detect obstacles: when there is no object ahead of the emitter, the receiver cannot detect signals; when there is an obstacle, the infrared light is reflected and is then detected by the receiver (it detects obstacles in a 0-7 cm range). The module presented here is sold by Sounfounder.

Example

In this example, an event is triggered when an obstacle is detected, or when the obstacle has disappeared. A message is simply printed in the standard output each time the status changes (obstacle detected / no obstacle).

Circuit

Example of use of an obstacle avoidance module - Circuit.

Program

public static void main(String[] args) {
    IRObstacleAvoidanceModule obstacleAvoidanceModule = new IRObstacleAvoidanceModule(GPIOPin.GPIO_00);
    
    obstacleAvoidanceModule.getGpioPinDigitalInput().addListener((GpioPinListenerDigital)
            (GpioPinDigitalStateChangeEvent event) -> Tools.log(event.getState().isLow() ? "obstacle detected" : "no obstacle"));
    
    Tools.sleepMilliseconds(15000);
}

Camera Pi

The camera module distributed by the Raspberry Pi Foundation is able to take pictures and videos. The Foundation distributes two versions of the camera module: the "regular" and the "Pi NoIR". The Pi NoIR camera module works exactly as the regular one, with one difference: no infrared filter is used. This allows to conceive projects to "see in the dark" (while pictures and videos taken by daylight will look rather curious!).

In the Raspoid framework, we implemented a complete wrapper for the raspistill and raspivid command line tools distributed by the Raspberry Pi Foundation. With our java wrappers, one can easily launch a preview window on a HDMI or PCB display directly connected to the Raspberry Pi, take still photos and videos. We also developed a solution to easily stream live video from the Raspberry Pi through the network with GStreamer, and we compiled a complete version of OpenCV (Open-source Computer Vision) to be fully compatible with the Raspberry Pi (rather tricky). All the required tools and components are installed in our Raspoid OS image.

Example

We will provide here one simple example for each category of features offered by the framework. It's impossible to list all the available methods here. We then recommend the user to look at the complete API to see all the offered capabilities..

The methods developed for this part of the framework are available in a static way. If the user needs to apply some specific modification on the image from the camera (vertical/horizontal split, width, height, opacity, resolution, exposure, etc.), we offer four configuration abstractions that can easily be used and then passed in argument of static methods. The CameraControlOptions refers to settings common to all images coming from the camera module: contrast, brightness, saturation, etc. The PreviewConfig, PictureConfig and VideoConfig entities are specific to the use of the corresponding features: width, height, output file name, quality, etc. Indeed, the range of available values for some options can be different for a picture, a preview or a video.

Circuit

Camera Pi connected to a Raspberry Pi 2.

Program

public static void main(String[] args) {
    // PREVIEW
    CameraPi.preview(5000);

    // PICTURES
    Picture picture1 = CameraPi.takePicture();
    Tools.log("New picture: " + picture1.getFilePath());
    
    PictureConfig pictureConfig = new PictureConfig("snowy_scenery", 2592, 1944);
    pictureConfig.setExposureMode(ExposureMode.SNOW);
    Picture picture2 = CameraPi.takePicture(pictureConfig);
    Tools.log("New picture: " + picture2.getFilePath());

    // VIDEOS
    Video video = CameraPi.takeVideo(5000);
    Tools.log("New video: " + video.getFilePath());
    String convertedVideoFilePath = video.convertToMP4();
    Tools.log("Converted file: " + convertedVideoFilePath);

    // STREAMING
    CameraPi.startGStreamerServer(NetworkUtilities.getIpAddresses().get(0), 
            NetworkUtilities.getAvailablePort(), 640, 360, true, true, 2500000, true, false);

    // OPENCV
    // Load the OpenCV native library.
    System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
    
    // Take a picture with the camera pi
    String pictureId = new SimpleDateFormat("yyyy_MM_dd_HH_mm_ss").format(new Date());
    PictureConfig pictureConfig = new PictureConfig("capture_" + pictureId, 640, 480);
    pictureConfig.setVerticalFlip(true);
    String filePath = CameraPi.takePicture(pictureConfig).getFilePath();
    
    // Look for faces
    Mat image = Highgui.imread(filePath);
    Rect[] faces = FaceDetector.detectFaces(image);
    Tools.log(String.format("%s faces detected", faces.length));
    
    // Create a new picture, with detected faces
    FaceDetector.surroundFaces(image, faces, "output_" + pictureId + ".jpg");
}