motionCenter

Overview

This software runs a web site to provide control of a swarm of motion-equipped cameras.

The system is intended to work with tclhttpd, a pure Tcl HTTP server, and motion, a motion-detection video software.

This is a distributed system, where one server is running tclhttpd and exports its storage space using NFS, while satellite systems are equipped with (one or more) camera, run motion and feed the server with video recordings.

This software is also capable of controlling Orvibo S20 WiFi sockets. These controls can be scheduled on and off at specific times of day, for specific days of the week. (The intend is to have in the future motion detection events to trigger light controls, e.g. light up backyard or front porche lights when movement is detected in this area.)

Architecture

The motionCenter software was designed for independent cameras controlled by the Motion software feeding a file server with motion capture videos. It provides a web interface built on tclhttpd, which gives access to these stored video files.

The web interface provides 2 main pages:

• A calendar page to visualise all motion detection events. This page shows a per-month calendar and a daily timeline for the selected day.
• A live video page to shows a mosaic of all configured cameras.

Each camera system registers its individual camera web interfaces (motion) periodically to the web server. This registration allows adding a new camera without changing the web server configuration. It also serves as a way to handle dynamic IP address allocation without relying on dynamic DNS.

It is possible to use a separate computer for each camera, the file server and the web server. In this case, it is assumed that access to the file server is provided using NFS and automount (using automount is critical for the system to recover properly from power outages).

Running the Motion software on the DVR itself would cause some significant CPU usage due to motion detection and video compression. Distributing the motion software over multiple small computers (e.g. Raspberry Pi 3 or FriendlyArm's Nanopi NEO) also makes the cabling easy when using analog cameras or USB webcams.

The typical configuration is to run the web server on the file server (a.k.a. DVR) and the Motion software on satellite (diskless) small computers.

File Organization.

Each motion capture event is identified by:

• a date (as a tree of directories: year, month, day).
• a time of day.
• a unique event identifier (server, camera, event number).

Each event is made of two files:

• a video file (only the MPEG4 / AVI format is supported for now).
• a JPEG picture that identifies the detected motion (see Motion's configuration).

See the file naming convention defined in the Motion configuration section below.

Installation Overview

Installing motionCenter involves the following steps:

1. Install and configure tclhtppd on the server.
2. Install and configure motionCenter on the server.
3. Install and configure motion on each camera system.
4. Install and configure motionCenter scripts on each camera system.

tclhttpd Configuration

The recommended configuration for tclhttpd is a follow:

• Install the original tclhttpd software in /opt/tclhttpd
• Install the tclhttpd configuration (tclhttpd.rc) as /etc/default/tclhttpd.
• Use the init script provided with motionCenter.

In addition, a patch must be applied to file lib/config.tcl. In proc config::init, replace:

interp expose $i file

with:

interp alias $i file {} file

The patch above is required because commit 35240baf0f4a245213ba4bf22e7310df06c6673d (2012) to the Tcl software changed the safe interpreter to block specific (deemed unsafe) subcommands of "file". The workaround is to execute "file" in the parent instead. This might break the security intent, but the official safe list is too restricted. Apparently tclhttpd.rc uses "file join", "file direname" and "file exists". "file dirname" was not listed as safe since this commit.

Installing and Configuring motionCenter on the server

The motionCenter software should be installed using the install.sh script. It is organized as follow:

• directory scripts contains the motionCenter software.
• directory public contains the motionCenter web pages.
• directory config contains the configuration files. You will need to edit theses files.
• directory videos is populated with the motion capture files.

The motionCenter system configuration is organized as follow:

The tclhttpd configuration (e.g. /etc/default/tclhttpd) is extended to define the installation path for the motionCenter software: Config motionCenter path.

The config/orvibo.rc file declares the Orvibo WiFi sockets. Each line defines a name, MAC address and IP address for one socket. For example:

orvibo declare wiwo1 DEADBEEF0001 192.168.1.151

orvibo declare wiwo2 DEADBEEF0002 192.168.1.152

...

the config/schedule.rc file defines the commands to execute at a specific time of the week. Each line defines the time, day of week, a randomization range and the Tcl command to execute. For example:

schedule -random 600 -time 05:30 -only Monday -command {orvibo on wiwo1}

schedule -random 600 -time 09:30 -only Monday -command {orvibo off wiwo1}

...

Motion Configuration

Motion must be configured to save all detection files to a file server also accessible to the web server. Motion must be configured as follow:

snapshot_filename %Y/%m/%d/%H:%M:%S-server:%t:%v-snapshot

picture_filename preview

movie_filename %Y/%m/%d/%H:%M:%S-server:%t:%v

timelapse_filename %Y/%m/%d/server:%t-timelapse

where server is the name of the machine where motion runs.

Installing and Configuring motionCenter on the camera system

The motionCenter software comes with two scripts:

• A first script (motion-transfer) is used to transfer the video recoding files to the web server. The recommended configuration is for motion to store the recording locally, and transfer all files (including old ones) at the end of the event. This way if the server is temporarily unavailable, each camera system will accumulate recording files until the server is back in operation. this script depends on the cleanlinks tool (see the xutils-dev package on Debian).

• Another script (motion-join) is meant to run as a separate service, periodically calls the web server to register the local motion's camera web interface. (For now this script only supports one camera per system.)

The motion software must be configured to invoke motion-tranfer at the end of each event (on_event_end). It can also be invoked when a video file is closed (on_moview_end) to transfer that file only (with "%f" as its parameter).