Note
This Bricklet is currently in the prototype stage and the software/hardware as well as the documentation is in an incomplete state.
This is the description of the Java API bindings for the Heart Rate Bricklet. General information and technical specifications for the Heart Rate Bricklet are summarized in its hardware description.
An installation guide for the Java API bindings is part of their general description.
The example code below is Public Domain (CC0 1.0).
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 | import com.tinkerforge.BrickletHeartRate;
import com.tinkerforge.IPConnection;
public class ExampleSimple {
private static final String HOST = "localhost";
private static final int PORT = 4223;
private static final String UID = "abc"; // Change to your UID
// Note: To make the example code cleaner we do not handle exceptions. Exceptions you
// might normally want to catch are described in the documentation
public static void main(String args[]) throws Exception {
IPConnection ipcon = new IPConnection(); // Create IP connection
BrickletHeartRate hr = new BrickletHeartRate(UID, ipcon); // Create device object
ipcon.connect(HOST, PORT); // Connect to brickd
// Don't use device before ipcon is connected
// Get current heart rate (in beats per minute)
int hrate = hr.getHeartRate(); // Can throw com.tinkerforge.TimeoutException
System.out.println("Heart Rate(bpm): " + hrate);
System.out.println("");
System.out.println("Press key to exit"); System.in.read();
ipcon.disconnect();
}
}
|
Download (ExampleCallback.java)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 | import com.tinkerforge.BrickletHeartRate;
import com.tinkerforge.IPConnection;
public class ExampleCallback {
private static final String HOST = "localhost";
private static final int PORT = 4223;
private static final String UID = "abc"; // Change to your UID
// Note: To make the example code cleaner we do not handle exceptions. Exceptions you
// might normally want to catch are described in the documentation
public static void main(String args[]) throws Exception {
IPConnection ipcon = new IPConnection(); // Create IP connection
BrickletHeartRate hr = new BrickletHeartRate(UID, ipcon); // Create device object
ipcon.connect(HOST, PORT); // Connect to brickd
// Don't use device before ipcon is connected
// Set Period for heart rate callback to 1s (1000ms)
// Note: The heart rate callback is only called every second if the
// heart rate has changed since the last call!
hr.setHeartRateCallbackPeriod(1000);
// Add and implement heart rate listener (called if heart rate changes)
hr.addHeartRateListener(new BrickletHeartRate.HeartRateListener() {
public void heartRate(int hrate) {
System.out.println("Heart Rate(bpm): " + hrate);
System.out.println("");
}
});
System.out.println("Press key to exit"); System.in.read();
ipcon.disconnect();
}
}
|
Download (ExampleThreshold.java)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 | import com.tinkerforge.BrickletHeartRate;
import com.tinkerforge.IPConnection;
public class ExampleThreshold {
private static final String HOST = "localhost";
private static final int PORT = 4223;
private static final String UID = "abc"; // Change to your UID
// Note: To make the example code cleaner we do not handle exceptions. Exceptions you
// might normally want to catch are described in the documentation
public static void main(String args[]) throws Exception {
IPConnection ipcon = new IPConnection(); // Create IP connection
BrickletHeartRate hr = new BrickletHeartRate(UID, ipcon); // Create device object
ipcon.connect(HOST, PORT); // Connect to brickd
// Don't use device before ipcon is connected
// Get threshold callbacks with a debounce time of 10 seconds (10000ms)
hr.setDebouncePeriod(10000);
// Add and implement heart rate reached listener
// Configure threshold for heart rate values,
// Heart Rate(in beats per minute) : greater than 70
hr.setHeartRateCallbackThreshold('>', (int)(50), (int)(70));
hr.addHeartRateReachedListener(new BrickletHeartRate.HeartRateReachedListener() {
public void heartRateReached(int hrate) {
System.out.println("Heart Rate(bpm): " + hrate);
System.out.println("");
}
});
System.out.println("Press key to exit"); System.in.read();
ipcon.disconnect();
}
}
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Generally, every method of the Java bindings that returns a value can throw a TimeoutException. This exception gets thrown if the device did not respond. If a cable based connection is used, it is unlikely that this exception gets thrown (assuming nobody unplugs the device). However, if a wireless connection is used, timeouts will occur if the distance to the device gets too big.
Beside the TimeoutException there is also a NotConnectedException that is thrown if a method needs to communicate with the device while the IP Connection is not connected.
Since Java does not support multiple return values and return by reference is not possible for primitive types, we use small classes that only consist of member variables. The member variables of the returned objects are described in the corresponding method descriptions.
The package for all Brick/Bricklet bindings and the IP Connection is com.tinkerforge.*
All methods listed below are thread-safe.
Creates an object with the unique device ID uid:
BrickletHeartRate heartRate = new BrickletHeartRate("YOUR_DEVICE_UID", ipcon);
This object can then be used after the IP Connection is connected (see examples above).
Returns the current heart rate measured.
If you want to get the heart rate periodically, it is recommended to use the listener HeartRateListener and set the period with setHeartRateCallbackPeriod().
Returns the version of the API definition (major, minor, revision) implemented by this API bindings. This is neither the release version of this API bindings nor does it tell you anything about the represented Brick or Bricklet.
Returns the response expected flag for the function specified by the function ID parameter. It is true if the function is expected to send a response, false otherwise.
For getter functions this is enabled by default and cannot be disabled, because those functions will always send a response. For listener configuration functions it is enabled by default too, but can be disabled by setResponseExpected(). For setter functions it is disabled by default and can be enabled.
Enabling the response expected flag for a setter function allows to detect timeouts and other error conditions calls of this setter as well. The device will then send a response for this purpose. If this flag is disabled for a setter function then no response is send and errors are silently ignored, because they cannot be detected.
See setResponseExpected() for the list of function ID constants available for this function.
Changes the response expected flag of the function specified by the function ID parameter. This flag can only be changed for setter (default value: false) and listener configuration functions (default value: true). For getter functions it is always enabled and listeners it is always disabled.
Enabling the response expected flag for a setter function allows to detect timeouts and other error conditions calls of this setter as well. The device will then send a response for this purpose. If this flag is disabled for a setter function then no response is send and errors are silently ignored, because they cannot be detected.
The following function ID constants are available for this function:
Changes the response expected flag for all setter and listener configuration functions of this device at once.
Returns the UID, the UID where the Bricklet is connected to, the position, the hardware and firmware version as well as the device identifier.
The position can be 'a', 'b', 'c' or 'd'.
The device identifier numbers can be found here. There is also a constant for the device identifier of this Bricklet.
The returned object has the public member variables String uid, String connectedUid, char position, short[] hardwareVersion, short[] firmwareVersion and int deviceIdentifier.
Sets the period in ms with which the HeartRateListener listener is triggered periodically. A value of 0 turns the listener off.
HeartRateListener is only triggered if the heart rate has changed since the last triggering.
The default value is 0.
Returns the period as set by setHeartRateCallbackPeriod().
Sets the thresholds for the HeartRateReachedListener listener.
The following options are possible:
Option | Description |
---|---|
'x' | Listener is turned off |
'o' | Listener is triggered when the heart rate is outside the min and max values |
'i' | Listener is triggered when the heart rate is inside the min and max values |
'<' | Listener is triggered when the heart rate is smaller than the min value (max is ignored) |
'>' | Listener is triggered when the heart rate is greater than the min value (max is ignored) |
The default value is ('x', 0, 0).
The following constants are available for this function:
Returns the threshold as set by setHeartRateCallbackThreshold().
The following constants are available for this function:
The returned object has the public member variables char option, int min and int max.
Sets the period in ms with which the threshold listener
is triggered, if the threshold
keeps being reached.
The default value is 100.
Returns the debounce period as set by setDebouncePeriod().
Enables the BeatStateChangedListener listener.
Disables the BeatStateChangedListener listener.
Returns true if the BeatStateChangedListener listener is enabled.
Listeners can be registered to receive time critical or recurring data from the device. The registration is done with "add*Listener" functions of the device object.
The parameter is a listener class object, for example:
device.addExampleListener(new BrickletHeartRate.ExampleListener() {
public void property(int value) {
System.out.println("Value: " + value);
}
});
The available listener classes with inherent methods to be overwritten are described below. It is possible to add several listeners and to remove them with the corresponding "remove*Listener" function.
Note
Using listeners for recurring events is always preferred compared to using getters. It will use less USB bandwidth and the latency will be a lot better, since there is no round trip time.
This listener can be added with the addHeartRateListener() function. An added listener can be removed with the removeHeartRateListener() function.
This listener is triggered periodically with the period that is set by setHeartRateCallbackPeriod(). The parameter is the heart rate of the sensor.
HeartRateListener is only triggered if the heart rate has changed since the last triggering.
This listener can be added with the addHeartRateReachedListener() function. An added listener can be removed with the removeHeartRateReachedListener() function.
This listener is triggered when the threshold as set by setHeartRateCallbackThreshold() is reached. The parameter is the heart rate of the sensor.
If the threshold keeps being reached, the listener is triggered periodically with the period as set by setDebouncePeriod().
This listener can be added with the addBeatStateChangedListener() function. An added listener can be removed with the removeBeatStateChangedListener() function.
This listener provides the current heart beat state.It is called every time a heart beat is detected. The state can either be
The following constants are available for this function:
This constant is used to identify a Heart Rate Bricklet.
The getIdentity() function and the EnumerateListener listener of the IP Connection have a deviceIdentifier parameter to specify the Brick's or Bricklet's type.