../../_images/ari-icon.png

[‼️ROS1] Meaning of ARI LEDs colors and patterns

There are four different LEDs displays in ARI, located on the ears, the microphone (on the front of the robot) and on the back.

Ears

Both ears have the same behaviour and the ARI’s ear LEDs have two default meanings:

  1. yellow and red blinking ears mean that battery level is under 20%. For more details check the battery how-to;

  2. blue and red blinking ears mean that an error on the motors occured.

../../_images/ARI_ear_LEDs.png

Back LEDs

The back LEDs have three default meaning:

  1. yellow and red blinking back LEDs mean that the batter level is under 20%. For more details check the battery how-to;

  2. blue and red blinking back LEDs mean that an error on the motors occured;

  3. if ARI is charging, back LEDs show the current charge level.

../../_images/ARI_back_LEDs.png

Microphone LEDs

The microphone LEDs are blue by default.

You can change the microphone LEDs colours yourself: see Tutorial: Creating expressions with LEDs.

../../_images/ARI_respeaker_LEDs.png

Example code

ari_leds_example.py
 1#!/usr/bin/env python
 2# -*- coding: utf-8 -*-
 3
 4# System imports
 5import rospy
 6from actionlib import SimpleActionClient
 7from pal_device_msgs.msg import DoTimedLedEffectAction, DoTimedLedEffectGoal,
 8LedEffectParams
 9
10
11# led devices ids
12BACK = 0
13LEFT_EAR = 1
14RIGHT_EAR = 2
15RESPEAKER = 4
16
17MAX_PRIORITY = 255  # The maximum value for leds effect priority
18
19
20def init_clients():
21    """ Initializing the action clients. """
22
23    # Creating a client object to communicate
24    # with the LEDs action server
25    led_client = SimpleActionClient("/pal_led_manager/do_effect",
26                                    DoTimedLedEffectAction)
27    led_client.wait_for_server()
28
29    return led_client
30
31
32def show_fixed_color(client,
33                     devices,
34                     r,
35                     g,
36                     b,
37                     a,
38                     duration_secs,
39                     duration_nsecs=0):
40    """ Setting up and sending a LedEffectGoal
41        for a fixed color leds effect
42    """
43    goal = DoTimedLedEffectGoal()
44    goal.devices = devices
45    goal.params.effectType = LedEffectParams.FIXED_COLOR
46
47    # Setting the colour parameters
48    goal.params.fixed_color.color.r = r
49    goal.params.fixed_color.color.g = g
50    goal.params.fixed_color.color.b = b
51    goal.params.fixed_color.color.a = a
52
53    # Setting non effect-specific parameters
54    goal.effectDuration.secs = duration_secs
55    goal.effectDuration.nsecs = duration_nsecs
56    goal.priority = MAX_PRIORITY
57    client.send_goal_and_wait(goal)
58
59
60if __name__ == '__main__':
61   try:
62      rospy.init_node('led_basic_tuto')
63      led_client = init_clients()
64      show_fixed_color(led_client,
65                      [BACK, LEFT_EAR, RIGHT_EAR, RESPEAKER],
66                      r=1,
67                      g=0,
68                      b=0,
69                      a=1,
70                      duration_secs=10)
71   except rospy.ROSInterruptException:
72     print("Abruptly finished!")

Code explanation

We import the required LEDs-related messages.

ari_leds_example.py
7from pal_device_msgs.msg import DoTimedLedEffectAction, DoTimedLedEffectGoal,
8LedEffectParams

Then, we define the different LEDs IDs.

ari_leds_example.py
10# led devices ids
11BACK = 0
12LEFT_EAR = 1
13RIGHT_EAR = 2
14RESPEAKER = 4
15
16MAX_PRIORITY = 255  # The maximum value for leds effect priority

Now, we are defining a set of functions that will be used later in __main__. The first function we implement is init_clients(), to initialise the client-server connection required to interact with the ROS action server involved in the LEDs management.

ari_leds_example.py
19def init_clients():
20 """ Initializing the action clients. """
21
22 # Creating a client object to communicate
23 # with the LEDs action server
24 led_client = SimpleActionClient("/pal_led_manager/do_effect",
25                                 DoTimedLedEffectAction)
26 led_client.wait_for_server()
27
28 return led_client

We will go through the definition of the function that initialises and sets the fields of a DoTimedLedEffectAction object, that is, the object sent by the node to the action server to request a specific LED effect. In this example, we will see how to set the Fixed Color effect.

ari_leds_example.py
32def show_fixed_color(client,
33                  devices,
34                  r,
35                  g,
36                  b,
37                  a,
38                  duration_secs,
39                  duration_nsecs=0):
40 """ Setting up and sending a LedEffectGoal
41     for a fixed color leds effect
42 """
43 goal = DoTimedLedEffectGoal()
44 goal.devices = devices
45 goal.params.effectType = LedEffectParams.FIXED_COLOR
46
47 # Setting the colour parameters
48 goal.params.fixed_color.color.r = r
49 goal.params.fixed_color.color.g = g
50 goal.params.fixed_color.color.b = b
51 goal.params.fixed_color.color.a = a
52
53 # Setting non effect-specific parameters
54 goal.effectDuration.secs = duration_secs
55 goal.effectDuration.nsecs = duration_nsecs
56 goal.priority = MAX_PRIORITY
57 client.send_goal_and_wait(goal)

At this point, we have all the functions that we need to run this example. In __main__, we can find how we call the two functions that need it.

ari_leds_example.py
62if __name__ == '__main__':
63   try:
64      rospy.init_node('led_basic_tuto')
65      print("init")
66      led_client = init_clients()
67      show_fixed_color(led_client,
68                       [BACK, LEFT_EAR, RIGHT_EAR, RESPEAKER],
69                       r=1,
70                       g=0,
71                       b=0,
72                       a=1,
73                       duration_secs=10)
74   except rospy.ROSInterruptException:
75      print("Abruptly finished!")

See also