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Getting Data

Accessing the data in a different node

To access the data being published by the tactile sensors, you just need to subscribe to each of the topic you're interested in. There's an example in the example folder.

Here is a very basic example to showcase this:

   1 #include <ros/ros.h>
   2 #include <std_msgs/Float64.h>
   3 
   4 void callback(const std_msgs::Float64ConstPtr& msg)
   5 {
   6     ROS_ERROR_STREAM("Touch value for the First Finger finger tip: "
   7                       << msg->data);
   8 }
   9 
  10 int main(int argc, char** argv)
  11 {
  12     ros::init(argc, argv, "test_tactile");
  13     ros::NodeHandle node_tactile;
  14 
  15     ros::Subscriber sub;
  16     sub = node_tactile.subscribe("/sr_tactile/touch/ff", 2, callback);
  17 
  18     ros::spin();
  19 
  20     return 0;
  21 }

The code explained:

• First we initialize the node and subscribe to one of the touch sensors topic:

   1 [...]
   2     sub = node_tactile.subscribe("/sr_tactile/touch/ff", 2, callback);
   3 [...]

• Then we print a message containing the value of the sensor in the callback function:

   1 [...]
   2 void callback(const std_msgs::Float64ConstPtr& msg)
   3 {
   4     ROS_ERROR_STREAM("Touch value for the First Finger finger tip: "
   5                       << msg->data);
   6 }
   7 [...]

Visualizing the sensor output

To visually check the sensor output, you can use rxplot. The following command displays the 5 finger tips tactile sensors in a plot:

$ rxplot /sr_tactile/touch/ff/data,\
         /sr_tactile/touch/mf/data,\
         /sr_tactile/touch/rf/data,\
         /sr_tactile/touch/lf/data,\
         /sr_tactile/touch/th/data