rosserial msg load

Question

Hi,

can someone please explain why it makes sense to generate the ros msg e.g. on the arduino ?

From the wiki and the code it looks like a lot of has to be done to generate a large message for the serial connection. Where from my experiences it can be unreliable on arduinos if messages are to big or to much time is needed for the generation.

if anyone has good experiences with rosserial_arduino e.g. on noisy sensors or can explain the approach ?

Thanks

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Originally posted by vKuehn on ROS Answers with karma: 116 on 2016-10-23

Post score: 0

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Original comments

Comment by gvdhoorn on 2016-10-24:
It's not in your question explicitly, but I'm getting the feeling that you have an alternative in mind. Perhaps add that to your question?

Comment by gvdhoorn on 2016-10-24:\

if anyone has good experiences with rosserial_arduino e.g. on noisy sensors [..]

And I'm slightly confused as to how this is connected to your "why do everything on the arduino" question.

Comment by vKuehn on 2016-10-25:
As described the implementation looks like it is creating a ros message on the arduino and than sends the complete message every time to the host if there is something. So a sensor would create some noise, right ? if that is not a problem did some one really succeed using this reliable ?

Comment by gvdhoorn on 2016-10-25:
Could be that I haven't had enough coffee yet, but I don't understand what the noisy sensor has to do with it. Unless you see the sensor somehow interfering with the sending/receiving of messages?

Comment by gvdhoorn on 2016-10-25:\

As described the implementation looks like it is creating a ros message on the arduino and than sends the complete message every time to the host if there is something.

What you describe is the 'event' pattern. That is one option. Cyclical polling (infinite while) is another.

Comment by vKuehn on 2016-10-25:
ok, this was the try to think about possible problems before encountering. I will use the stuff and come back with a more concrete thing. Thanks for trying to help

Comment by gvdhoorn on 2016-10-25:
I'd like to help if I can, it's just that I want to make sure I understand your question before trying to answer, hoping to avoid adding to the confusion.

Comment by gvdhoorn on 2016-10-25:
And rosserial has some problematic parts, for sure. Be sure to check out some of the other answers here on ROS Answers, and the main github repository as well.

Comment by gvdhoorn on 2016-10-25:
I'd still be interested in any alternative approach that you are thinking of? One that I know is ros_arduino_bridge.

Comment by vKuehn on 2016-10-25:
because of that I was curious if someone succeeded..sorry answerd below

Answer 1

for me worked so far a single character read/send stable over serial, especially when ftdi or wirless adapters where in between. So I thought something like a ros node would generate the message but the serial connection itself would be reduced to a bare minimum like char or int16 for values from/to the arduino. The ros_arduino_brdige seems to do something like that. Do you know where ros_arduino_msgs.msg comes from in that code ?

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Originally posted by vKuehn with karma: 116 on 2016-10-25

This answer was ACCEPTED on the original site

Post score: 0