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  • Heyhoe


       (0 reviews)
      Brand: Prefecon Oy
      Price: Free - £3
      Retailer: Google Play
      Value: 9
      Quality: 6
      Performance: 6
      Ease of Use: 6
      Kart Review Score: 6.75


    LapChrono is a simple stopwatch app which is designed to be used at the side of the circuit to time up to six drivers in the same session.

    The app is free to download and allows full access to the app for 7 days. Once the trial is over, you are limited to recording data to one driver.

    First Impressions

    When we say this app is simple, we mean SIMPLE! The whole app experience is dominated by the timing screen shown below.


    This screen contains 8 tiles, 2 for each driver/kart.

    The app shows tiles for 4 drivers by default and has the sector tiles set to 3 sectors.

    There is a simple menu at the top of the screen which includes; Driver Numbers, End Session, Reset Data, Number of Sectors, Save Data and Help.

    Aside from the simple menu dropdowns, that's all there is to it. It loads really fast and simplicity in an app like this is key.

    General Use & Observations

    The app is operated by tapping on either the outside or inside tile for each driver. The outer tile is a single lap, whereas the inner tile is used to break down the lap into sectors.

    Single Sector Lap (Outer)
    Tapping the outer tile for Driver 1 will start the lap. Tapping the same tile again will start the next lap and show you the previous lap time.

    Continuing to tap this tile on subsequent laps will also show you the best lap.

    Example of single sector timing. Purple indicates fastest lap of the session and yellow indicates the last lap.


    Multiple Sector Lap (Inner Tile)
    Tapping the inner tile will start the lap. Tapping the tile again will end S1 and start S2. Tapping once more will end S2 and begin S3. The next tap will end S3 and create a new lap starting with S1. Last lap and best lap data will be displayed on the outer tile.

    You do not need to tap the outer tile when using sectors.

    Example of multiple sector timing.  Sector times appear for the previous lap only. Best lap and last lap times are displayed in the outer tile.


    If you do not want to break the lap down into sectors, you can simply set the number of sectors to "No sectors". This will turn off the inner tiles and simplifies the interface further.



    You also have the option to assign your drivers race number to each driver.


    This will also show up in the data when reviewing after a session.

    The placement of the outer tiles is well thought out and allows you to use your thumbs at the edge of the screen without having to think about too much when concentrating on the kart. This works great for single sector lap timing.

    Multiple sector lap timing is slightly more difficult as you have to stretch further to tap the inner tiles. We think a good addition to the app would be the ability to switch the position of the tiles when sectors are enabled.

    Trying to time 4 karts with up to 4 sectors per lap is never going to be easy. It would require 16 taps in each lap which may only be 35-40 seconds long. That's a tap every 2-3 seconds! (That's assuming the karts are evenly spread over a lap, which they won't be!) I'm sure there are some experienced guys out there that could manage this, but it was too much for us!

    LapChrono tries to make the timing of your tap as accurate as possible by allowing you to hold the tile and release it when required. This was a little alien at first but does help as you can ensure you are holding the correct part of the screen and then look up to concentrate on the karts position.

    This is something which is unique to touch screen devices as a dedicated lap timer will usually have tactile buttons.  Once you are familiar with the device, you don't really need to look away from the track.

    Reviewing Data

    Once we have captured a session, you have to save the data to the phone. You do this by clicking on the save icon on the menu. All data is saved to a folder named prefecon.lapchrono in the devices folder system.

    To access these files you will need to navigate through your phone's menus or file manager app. Although storing a file on the device in a widely recognised format (in this case HTML) is very handy when you want to export it to some other software or device, it's not very practical. It would be great to be able to access the data from the app interface. 

    Below is the data which is stored in the HTML file.

    Test Data.png

    Again, we see a very simple screen with very little in the way of eye candy. The data is tabulated as you would expect.

    There is an attempt to format some of the data with colours but we are not sure this is working correctly. It appears as though the green sectors are the 2 quickest sectors per sector and the purple sector is... Well, we don't really understand the significance of the purple sector if we are honest. It's the quickest sector 2, but that's all we can tell from the data.

    An improvement to this would be to highlight data (fastest sector, best lap etc) on a per driver basis in one colour, and then use purple as the overall (All drivers) fastest sector, best lap etc. This would be widely understood as it's the standard in most motorsport timing applications.


    Let's not forget, this app is FREE! If you are after a utility to time a few drivers and also the ability to break the lap into sectors, it does the job.

    As touch screen interfaces go, it's simple to use and accurate. Capturing the data while the karts are on track is straightforward.

    What lets this app down is how it handles the captured data. There are no tools for naming or organising session data and no way of accessing the data from within the app.

    Once you view the data, it's basic raw data with questionable use of colours to highlight important data.

    We suspect these things will be improved on in a later release.


    • Free/Cheap
    • Simple
    • Easy to use
    • Multiple Sector functionality


    • No access to data within app
    • Lack of ability to organise sessions
    • Data presentation confusing/basic


    Edited by Heyhoe

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