cl_ros2_timer

Timer-based orthogonal behaviors for SMACC2 state machines. The OrTimer orthogonal holds a ClRos2Timer client; each behavior (CbTimerCountdownOnce, CbTimerCountdownLoop) creates its own dedicated wall timer for accurate, period-independent firing.

Setting Up the Orthogonal

Define an OrTimer orthogonal in your state machine:

// orthogonals/or_timer.hpp
#include "cl_ros2_timer/cl_ros2_timer.hpp"
#include "smacc2/smacc.hpp"

class OrTimer : public smacc2::Orthogonal<OrTimer>
{
public:
  void onInitialize() override
  {
    this->createClient<cl_ros2_timer::ClRos2Timer>();
  }
};

Register it in your state machine’s onInitialize():

void onInitialize() override
{
  this->createOrthogonal<OrTimer>();
}

CbTimerCountdownOnce

Header: cl_ros2_timer/client_behaviors/cb_timer_countdown_once.hpp

Posts EvTimer once after the specified duration, then stops. Use this to drive a timed transition out of a state.

// In state's staticConfigure():
configure_orthogonal<OrTimer, CbTimerCountdownOnce>(5s);    // fire once after 5 seconds
configure_orthogonal<OrTimer, CbTimerCountdownOnce>(4min);  // fire once after 4 minutes
configure_orthogonal<OrTimer, CbTimerCountdownOnce>(500ms); // fire once after 500 ms

Full state example:

struct StWaitForSensor : smacc2::SmaccState<StWaitForSensor, MyStateMachine>
{
  using reactions = mpl::list<
    Transition<EvTimer<CbTimerCountdownOnce, OrTimer>, StNextState, SUCCESS>>;

  static void staticConfigure()
  {
    configure_orthogonal<OrTimer, CbTimerCountdownOnce>(10s);
  }
};

CbTimerCountdownLoop

Header: cl_ros2_timer/client_behaviors/cb_timer_countdown_loop.hpp

Posts EvTimer repeatedly at the specified interval. Use this for periodic actions within a state.

configure_orthogonal<OrTimer, CbTimerCountdownLoop>(3s);    // fire every 3 seconds
configure_orthogonal<OrTimer, CbTimerCountdownLoop>(500ms); // fire every 500 ms
configure_orthogonal<OrTimer, CbTimerCountdownLoop>(1min);  // fire every minute

Chrono Literal Reference

Requires using namespace std::chrono_literals; — already in scope via rclcpp headers in standard SMACC2 state files.

Changelog for package cl_ros2_timer

::: note ::: title Note :::

This package was refactored in September 2025 from ros_timer_client. For historical changes prior to 2.3.20, see ros_timer_client/CHANGELOG.rst. The ros_timer_client package is now deprecated in favor of cl_ros2_timer. :::

3.1.0 (2026-05-31)

### Changed (Breaking) - cl_ros2_timer duration-based API (#61)

CbTimerCountdownOnce and CbTimerCountdownLoop now accept rclcpp::Duration via C++ chrono literals (5s, 500ms, 4min) instead of raw tick counts. Each behavior creates its own dedicated rclcpp::WallTimer, giving exact, period-independent timing with ~50ms residual from the SMACC2 SignalDetector 20 Hz polling loop.

Migration:

// Before (tick count, period-dependent)
configure_orthogonal<OrTimer, CbTimerCountdownOnce>(10);  // 10 ticks × timer period

// After (duration, period-independent)
configure_orthogonal<OrTimer, CbTimerCountdownOnce>(10s); // exactly 10 seconds

• ClRos2Timer is now a pure marker client — the duration constructor argument has been removed. or_timer.hpp files simply call createClient<ClRos2Timer>() with no args.

### Removed - CbRos2Timer — was unused in all reference state machines; removed. - CpTimerListener1 — now orphaned after the tick-stack removal; removed.

### Contributors - Brett Aldrich

2.3.20 (2025-11-01)

• New cl_ros2_timer unit test (#616)
• Refactoring cl_ros2_timer to header-lite (#617)
• Refactoring cl_ros2_timer to component-based architecture (#618)
• Refactored cl_ros2_timer components to header-only (#619)
• Refactor of cl_ros2_timer namespace structure (include paths) (#623)
• Update include path for cl_ros2_timer (#629)
• Moving reference library from ros_timer_client and keyboard_client to cl_ros2_timer and cl_keyboard (#645)
• Contributors: Brett Aldrich, Pablo Iñigo Blasco