James's Weblog

I’ve seen numerous people suggest purchasing a PDA over a physical graphing calculator. After all, a PDA can do everything a calculator can do (there are graphing calculator emulators that run on PDAs!), and it can do so much more. A PDA must be better, right?

I’ve spent the past three years in the PDA industry. I also own a physical graphing calculator. There are no doubts in my mind that a PDA is adequate for occasional use, such as for calculating sales tax or tips, but a physical calculator is superior for any extensive calculations, such as for math, science, or engineering work.

A physical calculator wins handily in the following key areas:

• Physical buttons with good tactile feedback. You want to be able to use the calculator to a reasonable degree without looking at it. You want to be able to feel for the button you want, and you want to be confident that the calculator registered the button press. Why do people prefer bulky physical keyboards to those flat, touchpad-like ones?
• Ease of use. People avoid touching PDAs directly for fear of getting fingerprints on the screen, and pulling out the stylus to tap on virtual buttons is clumsy. If you’re writing results out on paper, switching between a pen and stylus can be tedious.
• Battery life. My physical calculator lasts for years on a single set of batteries. PDAs need to be recharged frequently.
• Durability. PDAs are fragile. Physical calculators are rugged. A physical calculator can be thrown into a knapsack and jostled around without worry. Even if something breaks, a calculator is much cheaper to replace.
• Dependability. I trust the results from calculators of established manufacturers such as Texas Instruments and Hewlett Packard. Their calculators are thoroughly tested and have been used by engineers for ages. PDA software packages are made by less mature vendors who don’t have the same track record.

Plus, if you’re in high school, you really don’t have a choice, because PDAs aren’t allowed on standardized tests.

Some cool font/typography/letterform pages I’ve come across recently:

• Fontifier: turn your handwriting into your very own TrueType font!
• WhatTheFont?!: automatic font identification
• John Langdon’s Ambigrams
• The Scourge of Arial
• Ligature Schmigature

I know these things save lives and all, but I really hate the ones we have in our home.

When their batteries get sufficiently drained, they emit a short, annoying, loud chirp once a minute. It seems to me that whoever thought this up never lived in a home with a smoke detector in every room. It takes around 10-15 minutes to track down which smoke detector is complaining, because:

• We have a lot of smoke detectors.
• The chirp is too short to get a good fix on the location immediately.
• Funny acoustics can play tricks.
• I have to wait a full minute to refine each guess.

Ten to fifteen minutes isn’t a long time, but it’s longer than it ought to be. Listening to the shrill, piercing chirp doesn’t make the time spent any more enjoyable. (And why do these chirps always seem to start in the middle of the night while you’re sleeping?) The chirps seem to go on forever; just how low on power can the batteries possibly be? At my old apartment complex in Berkeley, I listened to one go on for weeks.

What I don’t understand is that the smoke detectors are wired to get power from the house. The batteries are supposed to be used only as a backup. How are they getting depleted so quickly?

Of course, a good high-tech solution would be to connect all the smoke detectors to a network and to have a central monitoring system.

Better low-tech solutions:

• Use a rechargeable battery; signal a warning only when the battery can no longer retain a sufficient charge.
• Use visual cues instead of (or in addition to) the chirps for battery warnings. For example, a smoke detector could turn off its power LED when battery power is low (and thereby save electricity too); it could release a short, brightly colored ribbon and let it hang; or it slide open a hatch that reveals some brightly-colored material underneath.
• Use less annoying chirps and chirp more frequently. It’s silly to design a smoke detector that can signal a low-battery warning for several weeks. Even two chirps in quick succession would be a huge improvement.
• Get a dog.