Find an online stopwatch to record time to .01 or .001 sec

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Homework Help Overview

The discussion revolves around finding an online stopwatch capable of recording time to the nearest 0.01 or 0.001 seconds, as part of a homework assignment related to measuring drop times for paper helicopters.

Discussion Character

  • Exploratory, Assumption checking, Mixed

Approaches and Questions Raised

  • Participants explore various online stopwatch options and question the feasibility of achieving high precision in timing. Some discuss human reaction times and suggest alternative methods such as using video recording to measure time intervals more accurately.

Discussion Status

The discussion includes multiple suggestions for online stopwatches and inquiries about the relevance of human reaction times. Participants are sharing resources and hints without reaching a consensus on the best approach.

Contextual Notes

There is an ongoing exploration of the accuracy limitations of human timing methods, with references to typical reaction times and the potential for using technology to enhance measurement precision.

MaryM
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My homework assignment asks "Record the drop time to the nearest 0.01 or 0.001 seconds". Is there a stopwatch online I can use? Thanks.

MaryM
 
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MaryM said:
My homework assignment asks "Record the drop time to the nearest 0.01 or 0.001 seconds". Is there a stopwatch online I can use? Thanks.

MaryM
Why would you want to do this? Your reaction response time is 0.1 at best.
 
fresh_42 said:
Why would you want to do this? Your reaction response time is 0.1 at best.
I am keeping track of paper helicopter drop times. Where is the .1 response time discussed? I would like to document that.
 
Welcome to the PF. :smile:
MaryM said:
My homework assignment asks "Record the drop time to the nearest 0.01 or 0.001 seconds". Is there a stopwatch online I can use? Thanks.

MaryM
Hint -- How many frames per second does your cellphone record for video? And how can you improve that resolution via interpolation? :smile:
 
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MaryM said:
I am keeping track of paper helicopter drop times. Where is the .1 response time discussed? I would like to document that.
Have you tried googling "human response time with a stop watch" ?
 
A common way to measure reaction time is to get a meter stick and a friend. This link explains how to do it. Most reaction times are between 0.2 and 0.3 s.

If your smartphone does not already have a stopwatch app, you should be able to download one. My phone's stopwatch display is to 0.01 s.
 
Depending on the problem and tools at hand you can get probably get better results by shooting a video with your cellphone (or any other camera) and measuring the time distance between frames where the process starts and ends (most video processing software display exact frame time).
 
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  • #10
MaryM said:
I am keeping track of paper helicopter drop times. Where is the .1 response time discussed? I would like to document that.
Here's a millisecond stopwatch code snippet that uses the JavaScript 'new Date' method:
HTML: 
<h3>Click to start or stop the stopwatch.</h3>
<div id="a" style="font-family: monospace; font-size: 11em">
0.000
</div>
<script>
b=onclick=function()
{b?(d=new Date,t=setInterval("a.innerHTML=(new Date-d)/1e3")):
clearInterval(t);b=!b}
</script>
You can copy and paste that and save it with a .html extension and run it in your browser.

Because of all the things happening in your system between mouse click and screen display you should rely on no better accuracy than within 5 milliseconds.

You can test your stopwatch actuation temporal accuracy for an anticipated event by trying to stop the timer at n.000 and seeing how close you get.

Just for fun, here's something a little more elaborate that I threw together for a gal who was spending too much billable time on the phone with her lawyer, talking about whatever instead of focusing on her legal concerns:
HTML: 
<!DOCTYPE html>
<html lang="en" >
<head>
<meta charset="UTF-8">
<title>Lawyer Phone Call Billing Timer</title>
<style>
body {
  background: #335533;
  font-family: "HelveticaNeue-Light", "Helvetica Neue Light", "Helvetica Neue", Helvetica, Arial, "Lucida Grande", sans-serif;
  height: 100%;
}

.wrapper {
  width: 800px;
  margin: 30px auto;
  color: #fff;
  text-align: center;
}

h1, h2, h3 {
  font-family: 'Courier', sans-serif;
  font-weight: 100;
  font-size: 2.6em;
  text-transform: uppercase;
}

#minutes, #seconds, #hundredths {
  font-size: 2.6 em;
}

#pennies, #dollars, #dollarsign {
  font-size: 4em;
}button {
  -moz-border-radius: 5px;
  -webkit-border-radius: 5px;
  border-radius: 5px;
  -khtml-border-radius: 5px;
  background: #112211;
  color: #fff;
  border: solid 1px #fff;
  text-decoration: none;
  cursor: pointer;
  font-size: 1.2em;
  padding: 18px 10px;
  width: 180px;
  margin: 10px;
  outline: none;
}

button:hover {
  -webkit-transition: all 0.5s ease-in-out;
  -moz-transition: all 0.5s ease-in-out;
  transition: all 0.5s ease-in-out;
  background: #fff;
  border: solid 1px #fff;
  color: #007755;
}
</style>

</head>

<body>

<div class="wrapper">
<h1>Time is Money</h1>
<h2>Lawyer Phone Call Billing Timer</h2>
<h3>
<p><span id=minutes>00</span>:<span id="seconds">00</span>:<span id="hundredths">00</span></p>
<button id="button-start">Start</button>
<button id="button-stop">Stop</button>
<button id="button-reset">Reset</button>
<p><span id="dollarsign">$</span><span id="dollars">0</span>.<span id="pennies">00</span></p>
</h3>
</div>

<script>
  window.onload = function () {

  var hundredths = 0;
  var seconds = 0;

  var minutes = 0;
  var pennies = 0;
  var dollars = 0;

  var appendHundredths = document.getElementById("hundredths");
  var appendSeconds = document.getElementById("seconds");
  var appendMinutes = document.getElementById("minutes");

  var appendPennies = document.getElementById("pennies");
  var appendDollars = document.getElementById("dollars");

  var buttonStart = document.getElementById('button-start');
  var buttonStop = document.getElementById('button-stop');
  var buttonReset = document.getElementById('button-reset');

var Interval ;

function bumpmoney () {
    pennies = ((seconds + (minutes * 60)) * 10.42);
    pennies = (pennies - (dollars * 100));
    pennies = Math.round(pennies);
    appendPennies.innerHTML = pennies;
    if (pennies > 99) {
          dollars++;
       pennies = (pennies - 100);
       if (pennies < 10) {
          appendPennies.innerHTML = "0" + pennies;
       }
       if (pennies > 9) {
          appendPennies.innerHTML = "0" + pennies;
       }       
       appendDollars.innerHTML = dollars;
    }  
}

buttonStart.onclick = function() {
    clearInterval(Interval);
    Interval = setInterval(startTimer, 10);
}

buttonStop.onclick = function() {
    clearInterval(Interval);
}

buttonReset.onclick = function() {
    clearInterval(Interval);
    hundredths = 0;
    seconds = 0;
    minutes = 0;
    pennies = 0;
    dollars = 0;
    appendHundredths.innerHTML = "00";
    appendSeconds.innerHTML = "00";
    appendMinutes.innerHTML = "00";
    appendPennies.innerHTML = "00";
    appendDollars.innerHTML = "0";
  }

  function startTimer () {

    hundredths++;

    if(hundredths < 10){
       appendHundredths.innerHTML = "0" + hundredths;
    }

    if (hundredths > 9){
       appendHundredths.innerHTML = hundredths;
    }

    if (hundredths > 99) {
       seconds++;
       money = bumpmoney();
       appendSeconds.innerHTML = "0" + seconds;
       hundredths = 0;
       appendHundredths.innerHTML = "00";
    }
   
    if (seconds > 9){
       appendSeconds.innerHTML = seconds;
    }
  
    if (seconds > 59) {
       minutes++;
       if (minutes > 9) {
          appendMinutes.innerHTML = "0" + minutes;
       }
       else {
         appendMinutes.innerHTML = minutes;
       }
       seconds = 0;
       appendSeconds.innerHTML = "00";
    }
   }
}
</script>
Here's a screenshot:

1591866902418.png


Line 103 sets the per-second rate at 10.42 cents, which comes out to the lawyer's billing rate of 375/hr (+ 12 cents due to rounding the seconds to the nearest hundredth) ##-## I view that as too much to pay for 'girl talk' when you're not especially wealthy . . .
 
Last edited:
  • #12
kuruman said:
A common way to measure reaction time is to get a meter stick and a friend. This link explains how to do it. Most reaction times are between 0.2 and 0.3 s.

If your smartphone does not already have a stopwatch app, you should be able to download one. My phone's stopwatch display is to 0.01 s.
Thanks. MM
 
  • #13
phinds said:
Have you tried googling "human response time with a stop watch" ?
Humans do not depend on response time when timing an event. The act of clicking the stop button is typically not a response. It is planned. We do not start clicking the button when we see the runner pass the line. We plan our action so that we finish clicking the button when the runner passes the line.

Accuracy to +/- 0.01 sec is about as good as I could do last time I played around trying to test this (many many years ago). See also this link.
 
Last edited:
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  • #14
Thanks to all of you. I am up to speed on web stopwatches and can now do it on my smartphone as well.

MM
 
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