Open Track and Field Timer

Open low cost timer to get accurate sprint times.

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I needed a better stopwatch to time my sprint workouts and found there weren't any affordable or open options. So It is time I make one for the community!

I wanted something with great flexibility so it allows multiple sensor inputs and is open hardware and software for people to adapt as needed.
Plan is to have an Android app to view sprint times and connect to timer. I will use MIT app inventor 2 making it easy to modify without Java knowledge.
Arduino code will be posted to github also.

All connections to lane sensors will be made with standard Cat 5e connectors and cables.
Design will keep soldering and drilling to a minimum with a parts count planning to be under $100

  1. Discuss the challenge the project addresses :

      Most track and field timing systems are 1000+ dollars or require physical people pressing buttons when crossing lanes. This makes it hard for lower income schools or individuals to have a quality timing system.

   2. Discuss how the project will alleviate or solve the problem that the project addresses.

      By lowering the cost students can accurately measure their performance so they can train sufficiently against other peoples times in sprint events such as the NFL combine sprint or olympic qualifiers.

  1. GitHub Link Here: Licensed under MIT liscense:


Latest Version of the App. Works Great.

package-archive - 2.68 MB - 05/09/2018 at 15:34


Ethernet Wiring.jpg

Wiring for Ethernet Jacks

JPEG Image - 785.33 kB - 04/13/2018 at 02:26


Sick Sensor Bracket.SLDPRT

Tripod Bracket or Sensor

sldprt - 204.00 kB - 04/13/2018 at 02:24


Sick Sensor Bracket.STL

STL of Tripod Bracket for Sensor

Standard Tesselated Geometry - 97.54 kB - 04/13/2018 at 02:24


Open Track Wiring Diagram.pdf

Notes on How to wire it up

Adobe Portable Document Format - 38.75 kB - 04/13/2018 at 02:23


View all 7 files

  • 1 × Arduino Uno R3
  • 1 × Leviton 42777-1WA Box
  • 4 × 6.8k resistor
  • 6 × 10k resistor
  • 3 × 50ft Cat 5e cable

View all 21 components

  • Real Testing

    Chaz05/09/2018 at 15:41 0 comments

    I took the setup to the high school track the other day and I was very happy with it.

    The sensors were easy to align, even in full sun.

    The LED ready indicator on the control box was very useful and all the times logged perfectly.

    If only I was faster. I want to shave 0.3 seconds off my 45m sprint and could not.... sigh.

    I also updated the app so I no longer get the bluetooth no connected error and there is a notification after you click save.


  • Kid tested....

    Chaz04/17/2018 at 15:51 0 comments

    I had my two kids practice sprinting in the hall. It was good fun.

    Setup is as follows:

    1. Set up tripods and align sensors.
    2. connect sensors with cat5e cables.
    3. plug in all the USB power supplies
    4. Confirm sensor alignment
    5. Connect via bluetooth with app.

    It is hard to tell if the app is connected so I have have a confirmatory light on the control Box. When you click the I'm ready button on the app it sends a signal to the box to light the LED and be ready. At least that way you feel good knowing things are working.

     6.  Then you run!

    After the last sensor trips it will send the times to your phone. you can enter a persons name and some notes if you want and click save if you want to save a text file to your phone with the times.

    See the Screen Shots below.

    Still to do: update app to improve Bluetooth connectivity notifications and have a notification to alert you that you clicked the save button and it was successful.

    I'll head to the track and get some real testing in once I crimp some 50ft cables and it stops snowing!

  • It's Alive!

    Chaz04/12/2018 at 14:50 0 comments

    I was able to get the system up and running. Each transmitter side of the photo sensors has a 5->12V usb boost adapter and a USB power brick. I have 8x tripods now to hold the sensors and need to still design the brackets and post the files for them. One of my sensors was bad FYI and allelectronics mailed me a new one for free :-).  The power requirements for the system is very low so you can use the cheapest $5 USB power bricks you can get. The app also works and can log data to a text file on your phone. A little work could be done to improve the Bluetooth handshaking but overall is functional. Next thing is for me to recreate the wiring schematic. 

    Parts I have added:

    1x Arduino prototyping Shield:

    8x Tripods:

    4x 12V USB Boost Adapters:

    5x USB Power Bricks:

    1 Gang Box: (replaces the 2 gang)

  • Woot! There is an app for this.

    Chaz04/06/2018 at 05:11 0 comments

    I will also publish the code in the files section.

    It is far from polished but is functional.

  • 4 buttons....

    Chaz03/29/2018 at 06:11 0 comments

    Initial rats nest on arduino works with 4 buttons and a bluetooth adapter. Annoying tidbit you need to have the usb unplugged if you want to use the bluetooth or vice versa.  Makes reprogramming slightly more annoying. Oh well.  Right now the systems waits for a ready "1" from bluetooth module. Then it waits for the first input to turn high. After that it waits for input 2,3,4 etc until all have been triggered and returns the difference in time between input 2,3,4 and the first input. In my case it will tell me my 15m, 30m and 45m sprint times times. Eventually someone might desire to make it more flexible where you can pass in the number of timers.  We will see when the app is made if I get to it or not....

    Code is on GitHub

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