Monthly Archives: November 2009

The Digital Textbook

Posted by on November 9, 2009 Comments Off on The Digital Textbook

The reason many developers become involved in open source projects is to “scratch an itch”, to fix a problem they are having with some software (or lack of existing software) when trying to accomplish something. Wikipedia works in much the same way, readers who see problems, omissions or errors (at least in theory) become editors fixing the problems. In general this works pretty well in terms of producing excellent output which meets the needs of the community, at least those contributing.

Textbooks have long been the domain of publishers and authors contracted by those publishers. K-12 textbooks especially have been notoriously inaccurate and out of date when it comes to sciences and technology. I think that openly licensed digital textbooks are set to change that. Much of the outdated information comes from the long lead time for traditional textbook editing and printing. When inaccurate information is found it is often either too late to do anything about it or the person finding it does not know who to contact to get the error corrected (or the person they contact can’t or won’t do anything about it).

The advantage of an openly licensed textbook is that any teacher or researcher who finds an error can correct it and republish the updated book. These “patches” can either be integrated upstream or “forked” in much the same way as is done with open source code. We certainly want schools and teachers using these textbooks to vet them prior to implementing them in the classroom, but this is not a problem with the model itself, it is just a shift from trusting the publisher to vet the textbook (was that ever a good idea anyway?) to trusting the school or district to do it. In some cases it may make sense to have some experts “certify” versions of the textbook as accurate as well. These certifications might also provide some kind of revenue model.

In addition, the fact that digital textbooks can be easily corrected and re-distributed or updated as new technologies emerge and discoveries are made helps keep information up-to date and as accurate as possible. Don’t get me wrong I think it will still be quite a number of years before schools are replacing all their textbooks, but the cost savings and advantages are significant so I suspect it will begin to happen sooner rather than later.

Two websites which are helping to move things in this direction and which are providing some digital textbooks to schools now are the California Learning Resources Network Free Digital Textbook Initiative and CK-12 Foundation.

Sharing Scanner Audio on the Internet

Posted by on November 9, 2009 Comments Off on Sharing Scanner Audio on the Internet

For a couple of years now the Gopher Amateur Radio club has been provding scanner feeds of the digital APCO-P25 in the Minneapolis/St. Paul metro area to radio enthusiasts around the world through the ScanAmerica.us website (now a part of the RadioReference.com family). In fact, I specifically purchased the fabulous GRE PSR-600 to replace the Radio Shack PRO-2096 because it allowed us to transmit the talkgroup identifier as well as the audio though some hacks attaching the remote control software to the stream broadcast software.

Thanks to K1PGV it looks like there is now some software called ScannerCast which integrates the polling function to get the talkgroup ID for both Uniden and GRE scanners which support it and tag the audio with the talkgroup. This is a much neater solution, if a little bit more limiting in that it doesn’t allow for simultaneous remote control of the radio.

DIY Book Scanning

Posted by on November 9, 2009 Comments Off on DIY Book Scanning

As regular readers will know I’m quite interested in the sharing of information. This includes support for projects such as the Internet Archive. One such example of their fantastic work is the sharing of public domain books which have been scanned, many by the ill-fated Microsoft book scanning project. Unfortunately, the Google Books project is (ironically perhaps) much more restrictive on licensing. My own feeling is that these books should be shared as much as possible and attaching new licensing restrictions to public domain books just because you have scanned them is ludicrous.

One potential solution to this is to scan books yourself but those that have done even more than a few pages of a book on a flatbed scanner know that this is a long a tedious process. The commercial scanners used by Microsoft, Google and the like are much more efficient but also much more expensive. Luckily the do-it-yourselfers have come along with their own book scanning solution. It’s not as elegant as the commercial scanners but it’s definitely inexpensive. Personally, I’m hoping someone comes along with something in the middle. A pre-built book scanning frame and platen which you can add cameras and accessories to and use with the open source software which has been developed.

You can watch the original Instructables video on building a DIY book scanner or visit the new DIY Book Scanning site with news and forums.

Fixing Liquid Spills on Electronics

Posted by on November 9, 2009 1 comment

If you’re brave and resourceful or just desperate enough it is often possible to bring back electronics from the dead after they have had liquid spilled on them. I’ve recently been working on a friend’s laptop which had water spilled on it. I’ve gone from it doing nothing at all to being apparently fully operational with the exception of the LCD backlight which I’m still working on. Note this can be a long process which requires drying time and lots of patience. This could easily stretch to weeks and many hours of assembly and dis-assembly work which is why it’s often a better bet to just replace the problematic component.

My own process involves dis-assembling everything and giving it a good scrubbing with a toothbrush and some very pure electronics grade alcohol followed by a scrubbing with contact cleaner. I then let everything dry out for a day or two and repeat. Re-assemble everything and test. Many times only certain things will not be working anymore which can give you some hints as to where to look for corrosion and areas of the printed circuit board which need further attention. It may take several iterations of this process before you arrive at something useful. One bit of good news about those small surface-mounted components which are difficult to replace in the field is that they are much easier to scrub down than their larger counterparts.

For more information and tips on bringing back liquid damaged electronics I suggest reading this article at GRYNX.