Package pt.unl.fct.di.tardis.babel.iot.demos

Class BabelChainableLedsHSBDemo

java.lang.Object
pt.unl.fct.di.novasys.babel.core.GenericProtocol
pt.unl.fct.di.tardis.babel.iot.demos.BabelChainableLedsHSBDemo
All Implemented Interfaces:
BabelDemo
public class BabelChainableLedsHSBDemo extends pt.unl.fct.di.novasys.babel.core.GenericProtocol implements BabelDemo
Demo: a strip of Grove chainable RGB LEDs animated as a travelling colour wave, expressed in the HSB (hue/saturation/brightness) colour model. On every tick a fresh colour is computed for the head of the strip (LED 0) and the previous colours shift one position down the chain, so the colour appears to flow along the strip.

This is the HSB twin of BabelChainableLedsRGBDemo: same hardware, same animation shape, but colours are described as three floats (hue, saturation, brightness) instead of red/green/blue bytes. The control protocol converts HSB to the wire format. Comparing the two demos shows that the colour model is just a choice of request type — the rest of the flow is identical.

Devices & control protocols used. One Grove chainable RGB LED strip (DeviceType.GROVE_CHAINABLE_RGB), driven through the DigitalOutputControlProtocol (protocol id 2300).

The teaching point. This application protocol never touches Pi4J, GPIO or the LED wire format directly. It only sends Babel requests (RegisterIoTDeviceRequest, SetMultipleChainableLEDColorHSBRequest) to the control protocol, which performs the actual GPIO work.

To run: java -jar <jar> ledsHSB (see Main.java).

Configuration. The strip length is read from the rgb.led.count property (via DigitalOutputControlProtocol.RGB_LED_COUNT, default 1) and the GPIO data line from led.line (default 24) — both in paradigmshift.config. See the project README for why line 26 must be avoided alongside a LoRa HAT.

Based on IoT-control demos originally developed at NOVA FCT for the TaRDIS project; provided and evolved independently by ParadigmShift.

  • Nested Class Summary

    Nested classes/interfaces inherited from class pt.unl.fct.di.novasys.babel.core.GenericProtocol

    pt.unl.fct.di.novasys.babel.core.GenericProtocol.ProtocolMetricsBabelMetrics

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final String
    LED_PORT
    Config key naming the GPIO data line the LED strip is wired to.
    static final String
    LED_PORT_DEFAULT
    Default GPIO line (BCM 24) — coexists with a seated LoRa HAT.
    static final String
    ledAlias
    Human-readable name we register the strip under, then verify in the reply.

    Fields inherited from class pt.unl.fct.di.novasys.babel.core.GenericProtocol

    babel, babelSecurity

    Fields inherited from interface pt.unl.fct.di.tardis.babel.iot.demos.BabelDemo

    PROTO_ID, PROTO_NAME

  • Constructor Summary

    Constructors
    Constructor
    Description
    BabelChainableLedsHSBDemo()
    Sets the protocol identity shared by all demos (BabelDemo.PROTO_NAME / BabelDemo.PROTO_ID) and seeds the colour RNG.

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    execute()
    Entry point for this demo (called from Main).
    void
    handleDemoTimer(DemoTimer t, long time)
    Periodic-timer handler: advances the animation one step.
    void
    handleRegisterIoTDeviceReply(pt.unl.fct.di.tardis.babel.iot.api.replies.RegisterIoTDeviceReply rep, short protocolId)
    Reply handler for the device registration.
    void
    init(Properties props)
    Wires this protocol's event handlers and starts device registration.

    Methods inherited from class pt.unl.fct.di.novasys.babel.core.GenericProtocol

    addSecret, addSecret, addSecret, addSecret, cancelTimer, closeConnection, closeConnection, closeConnection, closeConnection, closeConnection, closeConnection, createChannel, createSecureChannel, createSecureChannel, createSecureChannel, createSecureChannelWithAliases, createSecureChannelWithAliases, createSecureChannelWithIdentities, createSecureChannelWithIdentities, createSecureChannelWithProtoIdentities, enableGenericMetrics, generateIdentity, generateIdentity, generateIdentity, generateIdentity, generateIdentity, generateIdentity, generateIdentity, generateSecret, generateSecret, generateSecret, generateSecret, generateSecretFromPassword, generateSecretFromPassword, generateSecretFromPassword, generateSecretFromPassword, getChannelOrThrow, getDefaultChannel, getDefaultProtoIdentity, getDefaultProtoIdentityCrypt, getDefaultProtoSecret, getMillisSinceBabelStart, getOrGenerateDefaultProtoIdentity, getProtoId, getProtoName, hasProtocolThreadStarted, openConnection, openConnection, openConnection, openConnection, registerChannelEventHandler, registerMessageHandler, registerMessageHandler, registerMessageHandler, registerMessageHandler, registerMessageHandler, registerMessageHandler, registerMessageHandler, registerMessageHandler, registerMessageHandler, registerMessageHandler, registerMessageHandler, registerMessageHandler, registerMessageHandler, registerMessageHandler, registerMessageHandler, registerMessageHandler, registerMessageHandler, registerMessageHandler, registerMessageSerializer, registerMetric, registerReplyHandler, registerRequestHandler, registerSharedChannel, registerTimerHandler, sendMessage, sendMessage, sendMessage, sendMessage, sendMessage, sendMessage, sendMessage, sendMessage, sendMessage, sendMessage, sendMessage, sendMessage, sendMessage, sendMessage, sendReply, sendRequest, setDefaultChannel, setDefaultProtoIdentity, setDefaultProtoIdentity, setDefaultProtoSecret, setupPeriodicTimer, setupTimer, startEventThread, subscribeNotification, triggerNotification, unsubscribeNotification

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Field Details

    • LED_PORT

      public static final String LED_PORT
      Config key naming the GPIO data line the LED strip is wired to.
      See Also:

    • LED_PORT_DEFAULT

      public static final String LED_PORT_DEFAULT
      Default GPIO line (BCM 24) — coexists with a seated LoRa HAT.
      See Also:

    • ledAlias

      public static final String ledAlias
      Human-readable name we register the strip under, then verify in the reply.
      See Also:

  • Constructor Details

  • Method Details

    • init

      public void init(Properties props) throws pt.unl.fct.di.novasys.babel.exceptions.HandlerRegistrationException, IOException
      Wires this protocol's event handlers and starts device registration.

      Reply and timer handlers are registered before the request is sent, so the RegisterIoTDeviceReply cannot beat its handler into place. We then ask the DigitalOutputControlProtocol to register a chainable RGB strip on deviceLine; the handle arrives asynchronously in handleRegisterIoTDeviceReply(pt.unl.fct.di.tardis.babel.iot.api.replies.RegisterIoTDeviceReply, short). Finally the colour buffer is zeroed (all LEDs off).

      Specified by:
      init in class pt.unl.fct.di.novasys.babel.core.GenericProtocol
      Throws:
      pt.unl.fct.di.novasys.babel.exceptions.HandlerRegistrationException
      IOException

    • handleDemoTimer

      public void handleDemoTimer(DemoTimer t, long time)
      Periodic-timer handler: advances the animation one step. Shifts every LED's colour one slot down the chain, then computes a new HSB colour for the head (LED 0) from a random step value, and pushes the whole strip out via updateLedsColors(). Babel invokes this on its event loop because the timer was armed with setupPeriodicTimer once the device was ready.

    • handleRegisterIoTDeviceReply

      public void handleRegisterIoTDeviceReply(pt.unl.fct.di.tardis.babel.iot.api.replies.RegisterIoTDeviceReply rep, short protocolId)
      Reply handler for the device registration. Babel routes the RegisterIoTDeviceReply here once the control protocol has claimed the hardware.

      The pattern: check RegisterIoTDeviceReply.isSuccessful(); on failure, bail out. On success, keep the DeviceHandle (our only reference to the strip), paint an initial frame, and arm the periodic timer that drives the animation. The alias check guards against a mismatched reply.

    • execute

      public void execute() throws Exception
      Entry point for this demo (called from Main). Bootstraps Babel: grab the Babel singleton, load paradigmshift.config, instantiate the one control protocol this demo needs (DigitalOutputControlProtocol), register it plus this demo, init them in dependency order (control protocol first so its handlers exist before we send to it), then start the event loop.
      Specified by:
      execute in interface BabelDemo
      Throws:
      Exception