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81 lines
3.5 KiB
81 lines
3.5 KiB
3 months ago
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# EtherSense
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Ethernet client and server for RealSense using python's Asyncore.
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## Prerequisites
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Installation and Setup of Server:
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These steps assume a fresh install of Ubuntu 18.04 on an UpBoard but has also been tested on an Intel NUC.
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```
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sudo apt-get update; sudo apt-get upgrade;
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sudo apt-get install python
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sudo apt-get install python-pip
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sudo apt-get install git
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```
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Clone the repo then run:
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```
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sudo python setup.py
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```
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This will first install the pip dependencies, followed by the creation of cronjobs in the /etc/crontab file that maintains an instance of the Server running whenever the device is powered.
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## Overview
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Mulicast broadcast is used to establish connections to servers that are present on the network.
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Once a server receives a request for connection from a client, Asyncore is used to establish a TCP connection for each server.
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Frames are collected from the camera using librealsense pipeline. It is then resized and send in smaller chucks as to conform with TCP.
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### UpBoard PoE
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Below shows use of a PoE switch and PoE breakout devices(avalible from online retailers) powering each dedicated UpBoard:
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This configuration should allow for a number of RealSense cameras to be connected over distances greater then 30m
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The 5 RealSense cameras are connected to each UpBoard using the provided USB3 cables.
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### Client Window
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Below shows the result of having connected to five cameras over the local network:
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The window titles indicate the port which the frames are being received over.
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## Error Logging
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Errors are piped to a log file stored in /tmp/error.log as part of the command that is setup in /etc/crontab
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## NOTES
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### Power Considerations
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The UpBoards require a 5v 4Amp power supply. When using PoE breakout adaptors I have found some stability issues, for example the device kernel can crash when the HDMI port is connected. As such I recommend running the UpBoard as a headless server when using PoE.
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### Network bandwidth
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It is currently very easy to saturate the bandwidth of the Ethernet connection I have tested 5 servers connected to the same client without issue beyond limited framerate:
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cfg.enable_stream(rs.stream.depth, 640, 480, rs.format.z16, 30)
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self.decimate_filter.set_option(rs.option.filter_magnitude, 2)
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There are a number of strategies that can be used to increase this bandwidth but are left to the user for brevity and the specific tradeoff for your application, these include:
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Transmitting frames using UDP and allowing for frame drop, this requires implementation of packet ordering.
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Reducing the depth channel to 8bit.
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Reducing the resolution further.
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The addition of compression, either frame wise or better still temporal.
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Local recording of the depth data into a buffer, with asynchronous frame transfer.
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## TroubleShooting Tips
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I first of all suggest installing and configuring openssh-server on each of the UpBoards allowing remote connection from the client machine.
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Check that the UpBoards are avalible on the local network using "nmap -sP 192.168.2.*"
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Check that the server is running on the UpBoard using "ps -eaf | grep "python EtherSenseServer.py"
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Finally check the log file at /tmp/error.log
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There might still be some conditions where the Server is running but not in a state to transmit, help in narrowing these cases would be much appreciated.
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