RChrono is a chronometer watchapp for the PEBBLE watch.

Features are:

  • 30 lapsRChrono
  • Up to 999h59min59s
  • Final time calculation
  • Hydration timer
  • Heart rate measurement (manual procedure)
  • Auto-distance
  • Time display
  • Completely off-line (no need of a smartphone)
  • Data saved if you quit the application


Version: 1.42

Release date : 30/01/2014
Download PBW file:


  • 1.0: First release
  • 1.1: 05/12/2013 : New heart rate feature
  • 1.2: 06/12/2013 : New hydration timer feature
  • 1.3: 08/12/2013 : New interval timer feature. New settings menu
  • 1.42:30/01/2014 : Works with SDK Beta 7 and firmware V2


Originally I created RChrono for my TIMEX Datalink USB watch (10 years ago). Running GPS were not common, so I developed a chronometer that gave me an estimation of my final time in a marathon. I used it in some marathons before I bought a running GPS.
Now I have a PEBBLE and for some training I want to use it. While I’m training I don’t wear my phone so that’s why I decide to adapt my old program to the PEBBLE.

How it works?

First, RChrono is a standard chronometer with 30 lap’s capacity. The interesting feature is the final time calculation.

An example of use is better than a long description.
You want to run a marathon. In the setting menu, you set 42.2 for the final distance. At the beginning of the race you start the chronometer. Commonly on a marathon you have label each 5km (sometime each kilometers). At each label, you press the lap button, you enter the distance and the watch will estimate the final time. It will be updated each you time you enter a new distance.
In order to calculate the final time, the program calculates your average speed and estimate the final time assuming that you will continue to run at the same speed. Simple…
The Auto-distance feature allows the program to automatically add an amount of distance at each lap. For example, if you set 5 the program will add 5 to the distance each time you press the lap button. You will have just to validate the distance (or you can modify the distance).

The distance can be turns, miles, kilometers…

Navigation thru the pages

When you start the application, the “Chronometer page” is automatically displayed. After you have the following navigation thru the pages.


Buttons mapping

watch_with_buttons_numbers1 : Back button

2: Up button

3: Select button

4: Down button



How to use the application?

RChrono_Main_MenuOn the main menu, select RChrono to execute the application.RChrono is a watchapp and not a watchface. All the application data (Chronometer time, laps and options) are saved if you quit the application.
If you download a new application from the phone, the application data will be canceled.




Chronometer page


This is the main page of the application.From the top to the bottom you have:

  • The current time
  • An indicator that show that the chronometer is running
  • An indicator that show that the hydration timer is active
  • The watch battery level in %
  • The chronometer time with the hour (on the first line), the minute and the second (on the second line)
  • The last lap number
  • The last lap time
  • The current distance and the total distance
  • The final time

The buttons functions are:
UP button:

  • Short press: Turn on the light for a few second.
  • Long press: Reset the chronometer, the laps and distance.

SELECT button: Short press: Run or stop the chronometer.

DOWN button: Memorize the current chronometer time and display the LAP page.

BACK button: Display the application menu

Hydration alarm


If you turn on the “Hydration timer” in the chronometer page you will have periodically an alarm.The settings menu allow to activate the option and it’s duration.For example if you set 20 minutes you will have an alarm at 20min, 40min, 60min, 80min…


LAP pageRChrono_Lap

This window displayed the current lap number and the lap time.On the bottom of the screen the distance is displayed. If the AUTO-DISTANCE option is selected the distance is automatically increased.

The buttons functions are:
UP button: Increase the distance.

SELECT button: Validate the distance, calculate the final time, memorize the lap time and return to the main window.

DOWN button: Decrease the distance.

BACK button: Cancel the input and return to the main window.


Display after a lapRChrono_Chrono3

Again you can see the chronometer page where you have:

  • the display of the last lap number and time
  • the display of the current distance versus the total distance
  • the display of the final time

In this example the first kilometer was ran in 4min31. If you continue to run at the same speed the final time will be 41 minutes 40 secondes.


Application menuRChrono_Menu

This is the main menu of the application.
It allow to access to :

  • the chronometer page
  • the laps viewer page
  • the settings page

You also have the application version and the name of its wonderful author 🙂

The buttons functions are:
UP button: Select the previous menu item.

SELECT button: Display the selected page.

DOWN button: Select the next menu item.

BACK button: Exit the application and return to the main watch menu.


LAPS viewer pageRChrono_Lap_Viewer

On this page you have the list of all the laps.
On each line you have :

  • the lap number
  • the lap time
  • the distance associated to the lap

The buttons functions are:
UP button: Scroll the display up.

SELECT button: No action.

DOWN button: Scroll the display down.

BACK button: Return to the application menu.


Heart rate page


On this page you can measure your heart rate.
Follow this procedure (I wear my watch on my left arm):

  • Search your pulse with your left hand (on the neck it’s the easier). Put your right thumb on the UP button.
  • When you fell a pulse, press UP
  • Count 10 pulses
  • At 10th pulse, press UP. The heart rate is calculated and displayed.


The heart rate is in BPM (Beat Per Minute).

The buttons functions are:
UP button: Start and stop the procedure to measure the heart rate. Once the heart rate is displayed, another press restart the procedure and display “Search pulse”.

SELECT button: No action.

DOWN button: No action.

BACK button: Return to the application menu.


Settings menu


This page allows setting the options of the application.

Final distance:
Allow to enter the final distance.

Auto distance:
Allow to turn on/off the automatic distance feature.

Auto dist. value:
Allow to set the distance added at each lap (if the auto-distance feature is on).

Hydration timer:
Allow to turn on/off the hydration alarm feature.

Hydra. timer value:
Allow to set the hydration timer.

A first page allow to set the minute of the timer. A second page allow to set the second of the timer.

The buttons functions are:
UP button: Select the previous menu item.

SELECT button:

  • “Final distance”: Display the input page.
  • “Auto distance”: Toggle the option (On/Off).
  • “Auto dist. Value”: Display the input page.

DOWN button: Select the next menu item.

BACK button: Return to the application menu.


Final distance input


If you select «Final distance» you’ll have a first screen that allows entering the integer part of the distance. Once you press “Select” you will have a second screen that allows entering the fractional part of the distance.If you want to abort the input press the BACK button.

A comment, a request or an issue? Go to the forum.