Bob's Tech Talk
The do-it-yourself Corsi–Rosenthal Box can provide commercial-quality air purification for a fraction of the cost.
Q. I have a box of videotapes from the 80s and 90s that I would like to preserve on my computer. What do I need to make this happen?
A. This is easy to do once you have all the pieces you need.
The first piece is something to play the tape that has a video-out connector, such as a VCR or a camcorder.
The second piece is a computer with plenty of free disk space. Video takes up a given amount of space per hour depending on its format, info that can be found with a little research. Just ask Google how to calculate video file size. For example, 720p HD video will require about 1 to 4 GB of disk space per hour of video.
The third and final piece is most likely something you will need to purchase: A way to get the video from the playback device and into your computer. This piece is not going to be expensive, but it will take some research to figure out what works best with your devices.
The output of your playback device is almost certainly composite video in the form of RCA plugs colored red, white and yellow. Your computer probably has USB, either A or C. You will need a cable that will connect these two connectors together with a small dongle that does the video conversion. These dongles come with different connectors, so buy the one that matches your setup. These are plentiful on Amazon for less than $20 dollars.
A couple of caveats. If your computer has an HDMI port, that will not work. Those are output only connections and cannot be used to convert video.
If you have a Mac, the built-in QuickTime Player can record video sources, so no extra software is needed, just the dongle. If you have a PC, you will probably need software as well, and your best option would be a kit that includes multiple connectors and the recording software.
Q. A recent forest fire near me has me considering the value of a home air purifier. What do you think?
A. I do not have any personal experience with commercial home air purifiers, due both to expense and my preference for the DIY route. It is possible to build an inexpensive Corsi-Rosenthal Box. The background story of this device, which was developed during the pandemic, can be found on this link: en.wikipedia.org/wiki/Corsi–Rosenthal_Box.
In addition, here is a link to assembly instructions (one of many alternatives): http://www.texairfilters.com/corsi-rosenthal-box-modular-mini-small-quiet-and-effective/.
I live in fire-ravaged California, and we have experienced days where the air quality looked like the end of the world was in sight. Before you spend many hundreds of dollars on a commercial purifier, consider getting an Indoor Air Quality (IAQ) meter, which will help you measure the success of whichever method you choose.
Commercial air quality meters can be very expensive, but if you look for devices that include only a sensor whose output can be viewed on a smartphone or computer, you will find several for under $100.
Q. It is time to replace my old laptop. Of all the new models that are available, which one is a standout value?
A. Walmart.com is selling the MacBook Air for $699. That is an extraordinary value for a laptop that is durable enough to last at least five years. Metal chassis, bright 13-inch display, lighted keyboard, and exceptional sound.
This level of technology cost thousands of dollars five years ago, and the M1 MacBook Air is faster than almost anything else except for more expensive Apple laptop models and high-end Intel-based laptops that run Windows.
Although Apple apps are available on this laptop, it is fully capable of supporting everything you currently do online via familiar software. You can choose to use Google Chrome, Google Docs and Gmail for example.
Mix and match services that you are already using alongside Apple's built-in apps, or ignore Apple's apps entirely and use what you prefer.
This MacBook Air is the best of both worlds, in a slim relatively inexpensive package.
Wander the Web
Here are my picks for worthwhile browsing this month:
Apple Documentation
If you own any Apple device, bookmark this new URL. It leads to manuals and other support documents for every product they make, in one place.
https://support.apple.com/en-us/docs
American Literature Library
This site is a diamond mine of literary gems, everything from ancient fables and children's stories to classic novels.
https://americanliterature.com
The Constitution: That Delicate Balance
This series aired on PBS in the 1980s. It is only one small part of learner.org, a site packed with learning resources.
http://www.learner.org/series/the-constitution-that-delicate-balance
Bob has been writing about technology for over three decades. He can be contacted at techtalk@bobdel.com.
