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2017-04-26 08:17:07 -0500 asked a question Using a PING))) IR-sensor to stop when encountering obstacles

Using a PING))) IR-sensor to stop when encountering obstacles Hello! We're trying to create an "algorithm" for obstacle

2017-04-25 02:38:03 -0500 received badge  Popular Question (source)
2017-04-06 09:25:46 -0500 asked a question Multiple errors when controlling an MD23 with ROS

Hey all,

We are trying to control an MD23 motor using ROS. The idea is to have the motors running at all times, and when a message is published to the MotorControl channel stop the motors for a few seconds before resuming.

However, we keep running into [ERROR] : Unable to sync with device; possible link problem or link software version mismatch such as hydro rosserial_python with groovy Arduino and [ERROR] [1491487501.264662]: Lost sync with device, restarting...

We are running on an Arduino Uno. We thought we had fixed the first error by introducing a delay after the initialization, but after a few runs it came back. We're having a hard time understanding the second error. Are we pushing too much data over the port maybe?

The code can be found in the pastebin below:

Best regards,

2017-04-06 07:39:38 -0500 asked a question "Lost sync with device, restarting" - Controlling arms and head on a robot

Hi all!

We're currently working on a project involving a Meccanoid G15KS robot. We've implemented facial detection using a Kinect Camera, and are using an arduino to control the arms and head. The goal is to make the robot wave whenever he sees a face, as well as "look" at the person.

We've managed to get it working - he can identify faces and then notify the arms to make them wave. However, we ran into a problem where the camera wouldn't stop recognizing the same face if it stayed in the camera's view for too long (which is logical), causing the robot to wave forever. To solve this, we created a boolean variable called ReadyForFace and a rostopic called wavedone. When a face is identified, ReadyForFace is set to false and this makes the robot stop looking for faces. A message is published on the servo-topic, triggering the arduino code to make the arm wave. At the end of the wave, we publish a message on wavedone, and the callback function in the face recognition node then sets ReadyForFace to true.

This (seemingly) works, but we are constantly getting "Lost sync with device, restarting...". it's also not consistent - sometimes the robot will wave twice before crashing, sometimes up to 5 times. It also seems to not be dependent on the amount of time the nodes have been running. Some initial googling revealed that too long of a delay after spinOnce() can cause rosserial to crash, so we changed it from 300 ms to 1 ms, but it made no difference.

I've attached the arduino-code aswell as the face recognition node in the pastebins below (everything is very much a work in progress):

Arduino: Face:

Help is greatly appreciated!

Best regards,

2017-03-27 07:20:12 -0500 asked a question Image_transport tutorials - Crashes upon publishing an image to the topic


I've followed the tutorials to get started with image_transport. However, when i start the subscriber, the window created by the subscriber callback (the one titled "view") crashes when i publish an image (by running the subscriber). Also, it doesn't actually show the image from the parameter, but a small part of the desktop instead. Running on kinetic, ubuntu 16.04

Any help would be greatly appreciated!

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2017-02-28 01:41:52 -0500 commented question Trouble with ROS ZED wrapper

Hello again! I somehow managed to fix this problem, but unfortunately i don't really know. After restarting the terminal a few times it suddenly worked.

2017-02-24 03:02:28 -0500 commented question Trouble with ROS ZED wrapper

Yes, but it didn't fix the problem

2017-02-23 08:26:05 -0500 asked a question Trouble with ROS ZED wrapper


I am trying to get the ZED wrapper working for my project. I manage to build it succesfully, but when i run
roslaunch zed_wrapper zed.launch

i get the following: "ERROR: cannot launch node of type [zed_wrapper/zed_wrapper_node]: can't locate node [zed_wrapper_node] in package [zed_wrapper]"

I've followed the guide on . I have tried to delete the entire workspace and do it from scratch, but that didn't help.