Solved problems

2008-11-23 02:43:21 UTC

Here are some types of apps that I’m tired of seeing over and over again on the iPhone App Store. In some of these categories, I’ve picked a winner that completely solves the problem; you’re welcome to nominate winners for the others.

  • Flashlight (solution: myLite)
  • Tip calculator (solution: Calculator—seriously, is subtotal × 0.2 so damn hard?)
  • Any app with a checkmark icon, regardless of function: Think of a different icon, please. At this point, you might as well just make the word “app” your icon.
  • App to help you find your way back to your parked car: The main problem is that all of these use Core Location rather than just tracking movement through the accelerometer. That makes the app useless if you don’t have an iPhone 3G and you’re out of cell range or don’t have a cell antenna (iPod touch).
  • One-tap contact dialer (also includes 911/999 dialers)
  • Apps that fake receiving a phone call
  • Fortune-telling/decision-making apps
  • The Puzzle desk accessory
  • Sudoku (solution: ACTSudoku and its free light version)

There’s nothing wrong with competition, but these are saturated markets. If you’re not going to solve the problem in a completely different way (e.g., by not using Core Location to set the location of the parked car), then don’t waste your time—write something else.

If you have any suggestions for other categories that should go on the list, feel free to leave a comment.

8 Responses to “Solved problems”

  1. ssp Says:

    Subtotal / 5 might be even quicker.

    (Or going to primary school and catching up on division.)

  2. Jesper Says:


    The main issue with using the accelerometer is that it’s likely thrown WAY off unless you go directly from your car to the other location and then turn off the app directly. On your way back, you have to retrace the same exact path, including, if necessary, picking up your device and putting it down in the same way and in the same places. I haven’t even brought up yet how you’ll have to keep the accelerometer active for the entire path both ways. I wouldn’t even trust the accelerometer to deliver a half-assed pedometer.

    The deal with Core Location is that it affords you two coordinates, which means at worst an arrow (“it’s in this general direction”) and at best a map. That’s precisely the allure of such an application. If it’s a long enough distance that you have to use an app to keep track of it, you don’t want to exactly retrace your steps, because you likely won’t know them, given the whole “I don’t know where my parked car is” deal.

  3. Peter Hosey Says:

    ssp: Everyone I know expresses tips as a percentage, not a divisor, and the customary restaurant tip wasn’t always 20%. In the US, it used to be 15%. There’s no divisor for that, unless you multiply by 15 first. Multiplying by 0.15 and not dividing was quicker.

    Further, what’s so hard about × 0.2? When doing it in one’s head, both × 0.2 and ÷ 5 are just a shift right and a double; the only difference is the order.

  4. Peter Hosey Says:


    The main issue with using the accelerometer is that it’s likely thrown WAY off unless you go directly from your car to the other location and then turn off the app directly.

    Sounds fine to me. Keep in mind that, as an iPod touch user, I can’t use any of the current apps at all, so what you’re suggesting is an improvement. (Not that I have problems remembering where the car is, anyway…)

  5. Jesper Says:

    I didn’t properly revise my comment after I finished writing it, so you quoted the “wrong” sentence, so to speak. The main issue is that you have to take *exactly the same route back* to the car. And as the comment said, it is likely if you bought/downloaded and used such an app that you’d be having trouble doing exactly that, and the app would not actually be able to offer any help whatsoever.

    Seriously: what could it say? “I expect that if you walk in such a way that this device jiggles back and forth with a pitch of 4 cm/s for about five minutes and then you sorta pick it up as if looking at the screen in the middle of this and then you accidentally drop it and pick it up again…” If you *can* derive a map from accelerometer readings, it will be so fragile that actually using the device will throw it off significantly. And I have no idea where the sense of direction will come from.

    It may be so that you’re comparing the capabilities of the iPhone/iPod touch to the Wiimote. The Wiimote has an IR sensor in the front and a sensor bar that establishes a fixed reference location and the device’s relative position to it. The accelerometer doesn’t know shit here.

  6. Peter Hosey Says:

    Jesper: You would set the reference point by tapping a “start” button while at your car. The app should then use the device’s motion to track your motion, and use that to keep a running notion of where the car is relative to you.

    The display would not show a path as you imply. It would simply show an arrow. The ideal app would have a three-dimensional arrow that responds to the orientation of the device, so that if the device is directly between you and the car, you’re looking down the shaft of the arrow, and if you’re between the device and the car (i.e., facing away from the car), you’re looking at the arrow’s head.

  7. Jesper Says:

    a) The device’s motion is insufficient because it’s possible to move the device in absolute terms without affecting the detected relative motion.
    b) Even if the device’s motion would not be insufficient, the signal/noise ratio would be far too high to provide a useful result, and just the process of restoring the device into the exact location is more trouble than it’s worth.

  8. Labboc Says:

    The main problem with the accelerometer is that, unlike the wiimote, there is only one; rotation can’t be sensed as anything different from translation. The only way to get anything other than a random guess within a circle of how far you’ve walked is to not rotate the iPod while away from your car.

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