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.
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.
Good news sipdroid works with our Asterisk server. Following up on a lead I received from Ben Charlton at the JISCRI developers workshop last week, I tried running sipdroid on a borrowed G1 Android phone (big thanks to Paul Hogan). The default SipDroid pretty much works, but you need to set the nat setting in the Asterisk sip.conf file to yes (see sipdroid website – issue 15). No big deal but SipDroid does not authetnticate without it.
Once I got over the above registration issue, it was just a case of setting the Asterisk audio codecs to include alaw. Seems pretty OK – supports a steady audio stream. We could use this with a separate webpage displayed on the phone web browser for showing images and the video stream. Currently the SipDroid does not display a remote video and I was unable to get it to stream video from the phone within SipDroid, but audio is certainly doable.
Screenshot of Nanostation 2 bandwidth testing at Old Wolverton, displayed on Asus Eee PC running Ubuntu
Today we carried out our second set of field tests. This time using our new Ubiquity Nanostation2 wifi routers. In the morning Chris, Mark and John started with a radio site survey, then did a single wifi link of about 460 meters, and had a quick check of the video streaming software (mjpgstreamer) in one direction and a two-way voip call.
I met with Bob Spicer an OU lecturer who we will be workiung with when we go to our Durham residential school at the beginning of August. Bob will be tutoring on the SXR369 course and will be responsible for supporting the students with additional requirements. Bob was kind enough to go through the fieldwork locations and advise us on where the students access the sites and which areas they are interested in. This was really useful information for us as we can then go to the same locations when they are not being used by the students on the course in order to identify the best setup for each site.
Curious cows. A hazard that distinguishes our field testing from our lab based testing.
Today we did our first set of antenna tests as part of the JISC funded Portable VoWLAN project. We went out into the wilds of Old Wolverton and set up a pair of Linksys WRT 54GL routers at a distance of 100 meters in the morning and then a distance of 1.3 kilometers in the afternoon, to compare the performance of a range of antenna.
We used the iperf program to identify the (tcp) bandwidth and (udp) jitter values from a 60 second test. Here’s a quick summary of the findings…
ERA (Enabling Remote Activity) is an Open University project that supports remote participation by students in field trips. Using a wireless network, digital stills and video cameras, and two way audio communications, students are able to gather data and interact with colleagues in remote locations.
Thanks to a Rapid Innovation Grant from JISC we are investigating the potential use of Voice over Internet Protocol (VoIP) telephony to provide audio and video communication over a portable wireless network. This blog will be the place where we post details on the work being undertaken and our immediate findings.
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