Tf broadcaster dynamically changing values

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Hi guys,

my robot's sensor angle can be changed during its run so the transformations have to be dynamically changed. For now I have a node which reads pointclouds from the sensor, detects the angle of the sensor and publishes this information on a topic. Then I have a node which publishes transformations (a simple tf broadcaster):

ros::Rate rate(1000);
while(nodeHandler.ok()){
    broadcaster.sendTransform(
      tf::StampedTransform(
        tf::Transform(tf::Quaternion(0, detectedAngle, 0, 1), tf::Vector3(0.12, 0.0, 0.28)),
        ros::Time::now(),"base_footprint", "camera_link"));
    rate.sleep();
  }

I need the broadcaster node to read the message from the angle topic and use it in a detectedAngle variable, so it's always up to date. Now I'm not sure how the code should look like. I probably cannot use the typical subscriber syntax with ros::spin() as I have this cycle in the tf broadcaster. I could write a simple subscriber to the angle topic and publish the transformation in its callback function but I'm not sure if the transformation frequency would be enough (it would be the frequency of the sensor), or would be? Isn't there any tool in ros which could be used here? I imagine something like: the tf broadcaster node publishes transformation with some rate (e.g. 100Hz) and if some message come to the angle topic, the broadcaster updates the detectedAngle variable with the new value and continues publishing transformations.