Do visual timers work?

Is there a timer app that stays on screen?

If you want the app to be on-screen even when the screen is locked (when the phone goes to sleep), then there isn't a way to make an app stay on screen while the phone is locked. If you want the app to run while the phone is locked, then you must launch it from a time-sensitive action (such as a button press). The app will not remain on the screen even when the screen is locked, as the only thing that will keep it on the screen is pressing that button, which would otherwise be a long press.

Do visual timers work?

This question of course will only have a single answer: Yes or no.

Yes if the visual stimuli is clear and you can tell when you are being timed. No if the visual display has become so fuzzy that your eyes cannot really distinguish between the numbers in the timer. The problem with these timer displays is that they fail when it comes to accuracy. Most people need only a visual estimate of how many seconds they need to finish the time. And for that we already have the world clock, the clock display in your computer monitor, or your TV (or computer TV). There are many timers that are accurate all the way down to the nanosecond, such as the high-end time tracking software on most of the popular PC operating systems (including Linux).

What if you want more? Well what's the point of a time trial if you have to time yourself using a computer? If the purpose of a time trial is simple accuracy then why do most people use a stopwatch rather than a computer to time their bike runs? If you want more precision over several days of riding then why not time a person's performance against a digital stopwatch? And finally if you are a sport that takes place in multiple countries then it is hard to time your event without the use of stopwatches. The goal of a visual timer, whether it is the standard white box of numbers and two little lights, or any other type of timer display, is a timer that gives you the ability to watch as much as possible about your performance throughout a trial period. As an example there are a number of products on the market that let you time your bike for 2-5 minutes for multiple weeks. The best visual timer I have seen was the Cinelli Bike Time Test. It is easy to understand its function as it shows "time to beat" on a screen at all times. By simply setting the time before a ride this device will keep you honest by counting up while you ride allowing you to know where you are during the event. By setting times for several trials with varying durations you can also get some very interesting data from the performance graph built into the device. I have personally tested a number of timer devices for both indoor and outdoor applications. I used the Cinelli to time a number of time trials for three different events. The results were not at all what I expected and the Cinelli Bike Time Test is the only timer device I used for testing that was truly accurate.