Ben's Bits

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.

I'm not one who really enjoys writing code. In fact, I tend to avoid it whenever possible as it's just not that interesting to me. That said from time to time I have projects to complete where no existing software quite meets my needs and writing my own makes the most sense. This summer I was in the midst of collecting information and publishing a large extended family directory.

Clearly, the best way to do this is to store the data in a database. Because relational databases are most prevalent, I already have quite a bit of experience with MySQL and I knew I wanted to eventually make the data available via a PHP web application I decided to go with a MySQL backend. The trick here is that families aren't as relational as you might originally think. Families are really hierarchical data (parents, children, grandchildren, etc.) and relational databases have a hard time storing and recalling things based on these types of relationships. For example, a typical family query might be one for a list of all descendants of someone. As it turns out families aren't the only hierarchical data people might try to store in a relational database. Any business database which shows managers and reporting personnel is also a hierarchical data set albeit usually with fewer levels and much less complication (no need to track divorces, remarriages, spouses, etc.)

I was able to find and read up on several methods for storing the relational information but the one I ended up using is that proposed by Rob Volk of SQLTeam where the expensive (computationally) hierarchical relationships are stored in two additional fields for each record (depth and lineage) with parseable separators between generations. The database is initially loaded through a series of several (expensive) recursive queries but then can be maintained through triggers when information is added or updated.

Yesterday I was introduced to the TurboShear by Malco which is one of the greatest innovations I've seen in sheetmetal work. Instead of using a hand or electric shear for cutting the metal this devices chucks into your cordless drill and allows much more precise cutting (such as square corners) than electric shears and is much faster than hand shears. Shears also work well for cutting vinyl, steel mesh and other similar materials. Malco also makes a heavy duty and fiber cement board version of the product though for basic sheetmetal work such as HVAC ducting the standard TS1 seems to do the trick just fine.

I've written before about the various interesting applications for the Dallas 1-wire network such as HVAC control, access control, weather stations, etc. A few weeks ago I finally got around to ordering some 1-wire sensors to play with myself. I must say that I've had nothing but a good time with them. I'm currently running outdoor temperature and rainfall logging which you can see for yourself as the data is uploaded to a number of servers including Weather Underground and the National Weather Service (through the Citizen Weather Observer Program). In future postings I hope to discuss a bit more about how simple this was to get going and show off my own weather homepage (still in development).

For now I wanted to share the design for a 1-wire surge suppressor. As it turns out some people have had a problem, specifically with 1-wire weather equipment, with lightning inducting large currents into their 1-wire network and damaging the sensors and/or serial adapter. To combat this problem Philip Gladstone has posted some easy to build protection circuits for both 1-wire devices and the serial port adapter. While I haven't built them myself yet I hope to have some time to do so before storm season gets into full swing.

Those familiar with rapid prototyping (essentially 3D printers for computers) know that both machines and supplies can be extremely expensive. Now a group known as Fab@Home has published instructions and software for building your own rapid prototyping machine. The machine they propose is certainly not as durable or precise as the commercial offerings, but at a fraction of the cost it may serve your needs just fine. If all you're looking to do is a bit fo experimentation or introducing students to what a rapid prototyper can do a less expensive system such as this might be all you need. NewScientistTech also has a story on the Fab@Home project.