Low frequency (NXT-ROS with USB)

asked 2015-02-18 07:23:46 -0500

mikelom gravatar image


I'm trying to work on NXT-ROS using the USB. Right now I'm using an ultrasonic sensor, a color sensor and two servomotors. The problem is that I only get very low frequencies (~10Hz). If I raise the frequency of my sensors (for example up to 15Hz) I get something like this:

[WARN] [WallTime: 1424265476.725277] color_sensor not reaching desired frequency: actual 1.485489, desired 15.000000
[WARN] [WallTime: 1424265476.727759] ultrasonic_sensor not reaching desired frequency: actual 9.011199, desired 15.000000

I need a higher frequency for my application, but I don't know what is the problem.

I've read that there are some problems with frequency using the Bluetooth, but not with USB.

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I am seeing this also. My set-up is running ros-NXT over USB from a Raspberry PI. I have tried: Removing un-necessary USB devices from PI and then reducing all rates to 2 Hz. It respond to teleop_keyboard add but this is not adequate. Did you resolve this?

Derkabub gravatar image Derkabub  ( 2016-10-05 10:38:44 -0500 )edit

Well, it was along time ago and I don't remember exactly what we did. I don't know the state of NXT-ROW nowadays either. However I do remember that at the and we did some changes to a file (nxt.py or similar) to remove a wait time that had no reason and to remove some other things we didn't need

mikelom gravatar image mikelom  ( 2016-10-10 13:37:52 -0500 )edit

Thanks for the reply. I have a topic on this posted to the sig/NXT and someone there indicated the same. I will look over the nxt-python bindings as you are indicating.

Derkabub gravatar image Derkabub  ( 2016-10-10 21:06:36 -0500 )edit