Monthly Archives: November 2009

Portable VoWLAN: A portable voice over wireless local area network for mobile learning

Screen shots

Chris on Whitby foreshore testing voice and video; note headset and external camera, with field antennae in the background
JPERF graph from Scremerston
ERA kit on the beach at Scremerston
Base station at Saltwick test site.
Ekiga video call - fullscreen
Asterisk phone
Trevor testing a pair of Asterisk servers
Bluetooth on an Eee
Axis Q7401
Edimax MPEG-4 video in VLC
Edimax 3010wg
ERA2 SXR339 geology field trip
D-Link 3220g
Tutor and students at the ERA base location viewing the video feed and communicating via VoIP with the field geologist. Howick, Friday 07 August 2009
A portable wireless network used to improve access to geology field work locations

Description

The Portable VoWLAN Toolkit is a battery-powered wireless local area network, optimised for voice and video data. Developed for use in university geology field courses, the toolkit provides a 802.11g WiFi network, a VoIP telephony server, and streaming video. During a field trip students and lecturers can use VoIP softphones to talk to one another, and any web standards compliant browser to view streaming video and collected photos. Although developed to improve student access to geology fieldwork, the resulting generic toolkit can be applied to support any mobile learning context where live communication is required.

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Nokia LD-3W with Ricoh Caplio 500SE

Nokia LD-3W GPS module - a test shot taken at The Open University. The GPS location from the LD-3W is automatically included in the image file on the camera.

Nokia LD-3W GPS module - a test shot taken at The Open University. The GPS location from the LD-3W is automatically included in the image file on the camera.

We’ve just tried a Nokia LD-3W bluetooth GPS dongle with the Ricoh Caplio 500SE camera we’ve been using for taking photographs – and it rocks.

The LD-3W paired with the Ricoh bluetooth really easily (using the default PIN of 0000), the GPS signal details are then displayed on the camera’s LCD display and when an image is taken the current GPS co-ordinates are stored in the resulting image’s EXIF metadata. The battery in the GPS dongle seems to last all day and can be charged either using the car-charger cable that came with the device or a standard mains Nokia (skinny connector) phone charger.

This is a really easy way to GPS stamp our photos and for the money (£24.96 inc VAT) we’re very pleased with it.

Ubuntu 9.10 and Bluetooth audio.

Ubuntu 9.10 splash screenFollowing the release of the new 9.10 ‘Karmic Koala’ version of Ubuntu, we installed it on one of the Asus 901s, trying out a new configuration of all ext4 disk partitions and no swap partition. Discovering that the ‘Netbook Remix’ (UNR) release of the operating system now could only use the mobile phone look-alike interface and had the Desktop-Switcher package removed, we followed forum advice and tried the full Ubuntu 9.10 release instead. Having disabled the ‘wobbly windows’ graphics enhancements in Gnome, Ubuntu 9.10 was no trouble on the Asus 901 – all the devices worked from the start, dialogue and menu boxes fitted in the available screen area by default. One of the main reasons for trying Ubuntu 9.10 was to experiment with an early desire of ERA to use the bluetooth audio headsets commonly available for mobile phones instead of wired mic-and-headphones devices. With our Ubuntu 9.04 UNR installations we couldn’t get this to work, despite spending a frustrating day or two in early July with the latest software then available. At that time, improved bluetooth interaction with beta Pulseaudio releases and experimental device control with Blueman were not integrated into Ubuntu releases, but promised to make bluetooth audio as simple under Ubuntu as it is on a mobile phone.

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Cheap IP cameras: the Edimax IC-3010WG

Edimax 3010wgA much cheaper solution for IP video than the Axis Q7401, the Edimax IC-3010WG network camera is only £80 from use-IP.co.uk. For your money, you get a white plastic camera with a choice of wired or wifi network connections with a maximum resolution of 640×480 at 30fps. Video streams are available in either M-JPEG or MPEG-4, with a built-in microphone and 3.5mm audio-output jack. The lens is fixed focal length and autofocus down to about 25-30cm, there is a reverse-SMA connector for the supplied wifi antenna on top of the unit and a 1/4″W standard camera tripod thread unusually placed on the back. Continue reading