Boeing 737 Chronometer For FSX/P3D/P3DV2 Developed by Opencockpits Reviewed by Jack Whaley-Baldwin October 2014
For some, a chronometer is an interesting instrument; for others, it
is merely a fancy name for a watch. Despite its simplicity, there
exists the inescapable fact that the chronometer is one of the last
devices that simulator pilots take the time to use effectively. This
is, perhaps, somewhat understandable; a first time pilot is hardly
likely to want to spend his time fixated upon something that
measures only time.
In reality however, the chronometer is a fundamentally vital
instrument carried in one form or another in the cockpit of every
aircraft flying today. From being used to maintain a basic timed
track, to flying tightly accurate instrument procedures, the
chronometer is an essential piece of kit. Indeed, regardless of the
immense technical complexity of the most modern fly-by-wire
aircraft, there will always be at least one chronometer available at
all stages of flight for use by the crew.
In contrast to the proportionally lower demand for chronometers
within the flight simulation world, almost all of the well known
home-cockpit suppliers offer some sort of chronometer for hardware
The experts at Opencockpits have recently announced the release of
two USB-driven Boeing 737 chronometers; with one being a slight
upgrade of the other (differences explained in the next section). I
find myself in the fortunate situation of being able to review the
more upgraded of the two chronometers from Opencockpits, which aims
to be a complete, fully-functioning replica of a real 737
Overview and Pricing
As briefly touched upon above, Opencockpits offer two variants of
their Boeing 737 chronometer.
The first version, the Boeing 737 “Lite” chronometer, features all
the buttons and displays of the real 737 chronometer, with the
exclusion of the seconds hand needle. This version is suitable for
most simmers and cockpit builders who simply want a functioning
chronometer, as opposed to an identical replica. For a UK buyer, the
“Lite” chronometer will cost around €189, inclusive of both VAT
and shipping, which works out to be around £156. Considering that a
power supply and USB cable are included in the purchase, and that
the instrument is completely plug and play, I think that this is a
very reasonable price; I know some cockpit builders will be used to
paying more than double that for a similar instrument.
The second, and superior variant of the 737 chronometer, features
the addition of a working, stepper motor driven seconds hand needle,
as well as all the features offered with the “Lite” edition.
Essentially, this second variant is an exact, complete replica of a
real 737 chronometer, and is marketed towards those simmers striving
for the highest degree of realism; catering for the most minute
levels of detail that the cockpit building community has become
renowned for. Whilst some may argue that a seconds hand needle isn't
worth fighting over, those of you with home cockpits of your own
will know that the more instrumentation you have moving, the more
there is to show off.
Naturally however, this upgraded chronometer is more expensive (but
not drastically so!). Inclusive of VAT and shipping, a UK buyer will
be looking to pay around €261, around £215. This is £59 more
expensive than the “Lite” edition, however the benefits are
The feature list below details the full range of features for both
chronometers. Features that are only available to the upgraded
edition are shown in red. Several options can be changed as per
customer requests (eg 7 segment display colour).
- all buttons fully operational as per the real unit;
- full warm/cool white (as per request) backlighting;
- all 7 segment display units (white or orange, as per
request) fully functional, complete with decimal points;
- high quality engraved faceplate;
- plug and play USB 2.0 connection (USB cable included);
- 6V power supply included;
- fully functioning stepper motor
driven seconds hand needle;
- available in 737 gray or 747/757/767 brown;
- FS2004, FSX and X-Plane compatible; and
- full software management through SIOC interfacing software
(available free from Opencockpits).
Don't be scared by the last bullet point; Opencockpits have provided
a working SIOC script for the chronometer, which means that the user
does not have to have any SIOC experience to get the chronometer
working in full.
On another note, the fact that the chronometer is interfaced using
SIOC actually means that one can pull off a whole wealth of things
that you wouldn't normally expect a chronometer to do. If you so
desire, you could have the aircraft's altitude displayed in one of
the 7 segment displays, or perhaps use the clock-face as an airspeed
indicator! However, for the sake of sanity, this review will use the
chronometer as a timepiece only.
With the basics covered, it's time to look at the chronometer
My chronometer arrived in true Opencockpits style; in a box filled
with masses of over-the-top packaging – not that I'm complaining of
After eagerly (yet carefully) taking the chronometer out of the box,
I proceeded to give it a thorough visual inspection.
The first point of attention is that the chronometer looks, and
feels, like a very solid, compact unit. The entire array of Printed
Circuit Boards (PCBs), PIC microcontrollers, backlighting and the
stepper motor itself are all contained within a space behind the
faceplate no deeper than 70mm. The whole unit itself measures
110x110 mm in terms of height and width, and 80mm in depth.
It must be noted that the chronometer's circuitry is not enclosed
within any sort of case. This means that, although the circuitry is
shielded by the faceplate, the unit must be protected from dust and
liquid spillages (although such precautions should be common sense).
The reason for this is because cockpit builders love the flexibility
of being able to fit their purchased instruments/modules into their
own panels; as a result, excess casing and fittings are generally
The lack of casing does, however, reveal an advantage. It allows one
to view the internal wiring, and, yet again, everything is looking
top-notch in this respect. The majority of the wiring is very
efficiently arranged with the use of ribbon cables, and, where
ribbon cables have not been employed, free wires have been secured
well. Opencockpits' name is clearly visible on the black PCBs, which
indicate that these PCBs have been specifically engineered for use
with the chronometer; indeed, the PCBs have “IOCARD_CHRONO” printed
Although it's not normal that I pay this much attention to the
physical arrangement of electronic components, I think that in this
case, it is clearly visible that the developer has taken pride in
the appearance of their work; the whole unit has a clean, sharp feel
Connecting and Testing the Chronometer
Getting the chronometer working is a rather simple affair.
Firstly, the provided 6V power supply should be plugged into the
circular socket at the back of the chronometer. I must point out
that for UK users, a mains power adapter is necessary, as the 6V
power supply Opencockpits have provided features the two-pin
European style plug. This is, of course, not too much of a hassle,
and users can always use their own 6V supply should they prefer.
Upon connection of the power supply, the white backlighting of the
unit should illuminate, and the seconds needle should undergo a full
rotation as the stepper motor calibrates itself, before stopping at
the 60-seconds mark exactly (the “zero” position). More information
about the stepper motor itself can be found later in this review.
Note: If, for whatever reason, the seconds needle had not been
aligned with the 60-seconds mark prior to the connection of the
power supply, it should be now. If the needle is not aligned with
the 60-seconds mark, this means that the needle is not properly
aligned with the axle of the stepper motor, and will require a small
mechanical adjustment. Should you not feel comfortable with
adjusting the chronometer's needle yourself, I have no doubt that
Opencockpits would be willing to do so free of charge; they have
been most helpful in the past regarding such matters. In my case
however, the needle was, and remains, perfectly aligned with the
After the power supply has been connected, the USB cable should be
inserted into the chronometer and the other end of the cable plugged
into a free USB slot. The infamous Windows “ding-dong” should chime,
and the device should be successfully recognised as a USB device.
That's everything connected!
Since the stepper motor (hopefully!) underwent a successful
self-test routine when the power supply was connected, all that is
left to do is to test the tactile buttons and 7 segment displays of
For some reason that remains unknown to me, Opencockpits, in the
manual provided for the chronometer, provide a SIOC test script that
the user has to import into SIOC, successfully compile, and then
save in .ssi format, before reloading SIOC with this new, compiled
file. Whilst this is certainly not the most difficult of tasks, it
seems to me like a lot of needless hassle!
The latest versions of SIOC feature the “SIOC Monitor”, a powerful,
very simple to use piece of testing software that simply requires to
be clicked on in order to activate. Once activated, the monitor will
produce visual confirmation of any button presses, and features
individual output control which allows the user to control
individual 7 segment units. In my opinion, this is a much, much more
friendly, intuitive and interesting way of testing the chronometer,
and since Opencockpits developed the SIOC monitor themselves, I am
at a loss as to why they have not suggested using it in the manual!
Assuming that all has been plugged in, and assuming that you have
the latest version of SIOC installed, double click the SIOC.exe icon
to start SIOC. From the main SIOC window that appears, click on the
“SIOC Monitor” button. The following window should appear:
This window lists all of the IOCARD devices connected to your PC.
Assuming that the chronometer is the only Opencockpits product you
have connected, the window should appear as above (only one entry;
the chronometer). Note that the “Device = 235” entry will almost
certainly be different in your case; this number depends on the
exact USB port the chronometer was connected to, and varies from
computer to computer.
Double click on the “IOCard-Chrono” entry. This should bring up the
main testing interface, which has been annotated below:
Chrono Tester Annotated
From here, all the functions of the chronometer, with the exception
of the seconds needle, can be tested. The “outputs” in this case are
the decimal points of the 7 segment displays, which can be toggled
ON/OFF by clicking on their respective cells (20, 21 and 22). The
“inputs” refer to the individual tactile switches, and when a switch
is pressed, the respective cell should light up green.
The 7 segment displays of the chronometer can be tested through the
“Display Digits” section. Typing a number in the “Position” window
chooses an individual 7 segment display, and typing a number in the
“Value” window should send that number to the chosen display. The
7 segment displays are numbered as follows:
SIOC Monitor Numbering
NOTE: You may be curious as to why the interface allows numbers up
to 15 to be entered into a single 7 segment display. Entering a
number between 0 and 9 will result in that number being displayed;
however, entering a number between 10 and 15 will result in a
special character being displayed. These special characters are
10 – Blank Cell
11 – Hyphon (-)
12 - “Special” number six -
13 – Lower case “t”
14 – Lower case “d”
15 – Underscore (_)
The final points of attention are the “ALL ON/OFF” buttons. Clicking
on these will turn all outputs on and cause all of the 7 segment
displays to display an “8”. This, of course, is the simplest and
quickest way to test the chronometer.
Whilst I am convinced the one-click testing offered by the SIOC
monitor is much easier than using the aforementioned SIOC test
script, some users may prefer to use the latter.
Should you wish to test the chronometer using Opencockpits' SIOC
script, full instructions on how to do this are included in the
Opencockpits manual. The test script drives the chronometer such
that it functions how it would with FS2004/FSX/X-Plane running,
complete with seconds needle movement. However, since one will
(hopefully) be getting the chronometer running with Flight Simulator
anyway, I don't really think there is any need for it.
Using the Chronometer with Flight
Since the chronometer is interfaced to flight simulator using SIOC,
the device is extremely flexible in terms of what it will work with.
In fact, there is no reason why there should be any add-on software
that is incompatible with the chronometer, since the majority of its
functions rely only upon “background” flight simulator information
such as simulator time or date, which are obviously not
On the chronometer's product page at Opencockpits' website, a free
SIOC script is available to download which drives all of the
chronometer's functions without requiring any programming effort
from the user. This section will discuss the use of this script.
Assuming that you have downloaded the script in question, and saved
it to an accessible region of your hard-drive, start SIOC. The first
step is to configure the SIOC.ini file such that it will recognise
With the chronometer plugged in, from the main SIOC window, take
note of what is displayed in the “Devices” window. The number
displayed alongside the chronometer's entry is its unique identifier
(device number) for that particular USB port. Having noted this
number, click the “EDIT .Ini” button.
SIOC Window Device Number
A text file should pop up; this is the SIOC.ini file, which will
require two simple edits in order to use the chronometer. Simply add
to the end of the script, giving it a line of its own, the following
Where X is the aforementioned device number for the chronometer
(note that this number will change if you plug the chronometer into
a different USB port). Secondly, find the entry:
Where Y is any name of your choosing; this is what we will save the
SIOC file as later. Logically, you may wish to choose a name such as
Click “file”, and then “save”. Once again, the main SIOC window
should be visible.
With the SIOC.ini file configured, all that is left to do is import
the script that Opencockpits have provided.
Click on the “Edit Script” button. Then, from the window that
appears, click “File”, and from the drop down menu select “Import
Edit Script Window
A windows explorer interface will then pop up, from which you should
navigate to the text file you downloaded from Opencockpits' website.
Select the text file and then click “Open”. This will import the
file into SIOC and convert it into .ssi format. If all is
successful, the following window should appear:
Click “OK”. The import process is now complete; now all that's left
to do is to save the imported file to the main SIOC folder. From the
script window, click “File”, “Save As”, and then navigate to the
main SIOC folder (usually found in C ? Program Files x86 ? IOCards ?
SIOC). Make sure that you save the file with the exact same name you
used in the CONFIG_FILE entry above.
That's everything done!
Opencockpits' product page states that the script that we have just
installed above only works for the default B737. However, I have
used the script discussed above without any problems on a huge
variety of flight simulator aircraft (both payware and freeware
add-ons). Indeed, I have yet to find an aircraft that the script
doesn't work with.
Close everything SIOC-related down, and fire up flight simulator.
Select an aircraft of your choice, and, once your flight has loaded,
start SIOC. The chronometer's 7 segment displays should then spark
to life whilst the seconds needle makes a single complete
Using the Chronometer with the
This section applies only to those using the Level-D Simulations
Nico Kaan, the developer of the popular cockpit-building program
Lekseecon, which connects SIOC to the
Software Development Kit (SDK) of the LDS-767, has also produced a
special executable file that offers one-click interfacing for
Opencockpits' USB modules. The advantage to this is that if using
the LDS-767, absolutely no SIOC related work is required whatsoever;
simply running this executable file will instantaneously configure
To use this program, simply download Lekseecon (free of charge) from
his website http://www.lekseecon.nl
the executable file is installed alongside Lekseecon. Nico has also
produced a detailed, comprehensive manual (also installed alongside
Lekseecon) which explains everything.
Another advantage to using Nico's software is that it ensures that
the chronometer needle remains fully synchronized with the on-screen
needle of the simulated aircraft. Furthermore, Nico's software
provides full cold and dark functionality; that is, the chronometer
will not function at all unless the aircraft electrical systems have
been suitably configured in flight simulator.
Before we take a look at how well the chronometer's individual
features perform, this section will give a brief overview of the
functionality of the chronometer when working with flight simulator
with Opencockpits' supplied chronometer script.
CHR: Starts or stops the chronometer
TIME/DATE: Cycles the top row of 7 segment
displays between time and date (time (HR:MIN) ? time (MIN:SEC) ?
year ? date (DAY:MONTH))
SET: Pressing this will cause part of the
top row of 7 segment displays to flash, and allow you to change
their value using the +/- keys. It should be noted, however, that
the chronometer automatically synchronizes to flight simulator date
and time upon initiation of a flight, and so the time/date entries
should already be correct. Once the desired value has been set,
pressing this key again will allow you to change another value. To
confirm the adjusted value(s), keep pressing SET until the displays
stop flashing (very similar to the old Casio digital watches!).
+/- Keys: Change the value of a selected
ET: Pressing this key will cause the lower
row of 7 segment displays to read Elapsed Time (ET). Pressing the
key for a second time will start the elapsed timer, and pressing the
key for a third time will stop the elapsed timer (and pressing it
again will start it, and so on). The beauty of the elapsed timer is
that it can run seamlessly alongside the “normal” chronometer timer
(using the CHR) key; pressing CHR twice whilst the elapsed timer is
running will start such a timer, and pressing the ET key at any time
will return the lower display to reading elapsed time. It's all a
bit fiddly to explain and (understand!) unless you actually have the
chronometer in-front of you.
RESET: Resets a timer (ET timer or
“normal” timer). Upon being pressed, the timer's values will reset
to zero, and the seconds needle should rotate clockwise all the way
back to the start position, ready to be used again.
There are several other impressive features that Opencockpits'
chronometer script includes, and for full details one should refer
to the manual. One of my personal favourites is that if the CHR and
RESET keys are pressed simultaneously, the lower display will go
dark, allowing just the upper display to be used as a time/date
reference; the neat thing being that the seconds needle will deflect
to the 45-seconds position, giving you an uncluttered view of the
Time to asses how well the chronometer delivers!
As a Whole...
All in all, I have little hesitance to say that the chronometer
really is a beautiful little unit. As touched upon before, it has a
nice compact, robust feel to it. At the time of writing this review,
I have not encountered a (single!) problem or point of concern with
the chronometer, which really suggests that Opencockpits have upped
their game in terms of the quality of their products. Historically,
I have always encountered a few software-based or documentation
related (though never with the hardware itself) problems with some
of Opencockpits' products, but this chronometer really feels
different. I am thoroughly impressed!
Both the seconds scale and the surrounding faceplate of the
chronometer are fully backlit, which is powered by the 5V power
supply. Keeping in line with the rest of the unit, the backlighting
is crisp and clean, with no light bleed-through.
The backlighting certainly looks rather impressive at night, and as
well as serving as a nice visual feature, also does a good job at
doing what it's supposed to do; illuminating the crucial components
of the chronometer.
Since the backlighting is powered exclusively by the 5V power
supply, there is a potential downside; the backlighting cannot be
turned off. Whilst this may not be of concern to non
cockpit-builders, those with fully fledged cockpits will, of course,
have the desire to disable the chronometer's backlighting when the
aircraft's electrical systems have been turned off. This can very
easily be solved by connecting the 5V supply socket to an output of
an I/O Card of your choice; just make sure that this output is
capable of providing a reliable source of current (since the 5V
supply also powers the chronometer's stepper motor).
It has rightfully been given a lot of attention already in this
review, but the stepper motor deserves a section of its own.
After extensive use of the chronometer, it is evident that it is a
high quality, durable component. In my previous experience with
stepper motors, I found that it was reasonably difficult to source
one that was reliable; problems were often encountered involving
erratic needle movement. The chronometer's stepper motor has no such
problems. For the record, the stepper motor is of the
unipolar type; I mention this because cockpit builders
will certainly be aware of the existence of unipolar and bipolar
Another impressive point of mention is that throughout its rotation,
the needle remains well aligned with every single seconds detent on
the faceplate. Since the 7 segment display has the ability to count
the exact number of seconds elapsed, this degree of accuracy may not
be drastically important for casual simmers, but it is vital to
cockpit builders who strive for perfection.
This leads onto another very important issue. The way in which the
needle moves depends directly upon how the script that drives the
chronometer has been designed. Earlier in this review it was
discussed that one could use the default script provided by
Opencockpits, or perhaps the script provided by Nico Kaan for use
with the LDS 767 program. Personally, I have noted that
Opencockpits' script is somewhat smoother; this is because Nico's
script aims to syncronize the chronometer with the one in the LDS
767's panel, hence any imperfections in the panel needle's movement
will be transferred to the chronometer.
The reality is that there is no restriction to how the chronometer's
needle can be programmed to rotate. Both Opencockpits' and Nico's
script emulate the “clock” style of seconds needle; that is the
needle “ticks”, there is one movement per second of time elapsed.
However, some people seem to prefer the continuous rotation type of
seconds needle (like that found on the more expensive wristwatches);
this should not be impossible to achieve, although a reasonable
amount of SIOC knowledge would be required. Alternatively, one could
always root around in the many SIOC scripts available through the
cockpit building community to see if someone has already produced
such a script.
Faceplate and Engraving Quality
Once again, full marks here. All engravings into the faceplate
material are very clear cut and well defined; there is no “blurring”
of label edges. If one gently runs his finger against the engravings
of the faceplate, it is possible to “feel” the depth of the
engravings, which, in the case of the chronometer, have a lovely
high quality texture to them. Whilst such details are probably of no
interest to most people, they are, similar to other details
mentioned in this review, of interest to cockpit builders. In fact,
some hardware manufacturers even differentiate their pricing such
that different engraving techniques and faceplate materials work out
to cost different prices.
The faceplate and clock scale also accompanies the backlighting very
nicely; giving it a nice warm feel.
Buttons and Switches
The simple design of the chronometer is such that it features only
eight, identical simple switches. As is the case with the real unit,
all of the push buttons are tactile; that is, they give a
confirmatory “click” when pressed. The switches are solid and have
survived the several months I have owned the chronometer well. That
being said, they are just switches, so there's not really a lot that
can go wrong here!
7 Segment Displays
The chronometer plays host to two four-digit rows of 7 segment
displays, the functions of which have already been discussed at
length. As with most of their products, Opencockpits offer the
7 segment displays in either orange or white, and although their
website is not particularly clear about this, I believe the white
variant costs slightly more as, for reasons unknown to me, white
7 segment displays are more expensive than orange ones.
The 7 segment displays are recessed behind the clock face very
nicely and blend in very well with the unit. They are very crisp and
legible and really add the finishing touches to what is a most
A point of mention is the inclusion of decimal points in the
7 segment displays. There are three decimal points in total; a
single decimal point at the centre of the top row of displays, and
two decimal points on the bottom row of displays, with one at the
centre and one at the end of the displays. The purpose of these
decimal points is dependent entirely upon what the author of the
SIOC script has instructed them to do; the most obvious use of them
being to separate minutes and seconds (or hours and minutes).
The only (minor) complaint here is that in the real unit, the
“decimal points” are actually colons, as is the case with the vast
majority of digital time formats. For example, in a real Boeing
chronometer, “twelve minutes and twenty-seven seconds” would look
like this: 12:27
However, due to Opencockpits' use of decimal points instead of
colons, it actually ends up looking like this: 12.27
The reason for this is obvious, and will be immediately apparent to
many cockpit builders. Simply put, 7 segment displays with decimal
points are much more standard and commonplace (and hence easier to
obtain) than 7 segment displays with built in colons, which are
naturally going to be more expensive due to their rarity. However in
Opencockpits' defence, other hardware manufacturers appear to have
done exactly the same thing, and so it is perhaps unfair to fixate
upon this particular issue. But, does it really matter?
I have a prepared a video which shows the chronometer in action.
Opencockpits have provided an 11 -page PDF manual to accompany the
chronometer. Although there are some translation errors, this manual
is leaps and bounds ahead of Opencockpits' previous documentation;
it is very detailed and contains step-by-step image based
instructions on how to compile and configure the SIOC scripts, much
like I have done so earlier in this review.
Previously, some of Opencockpits' manuals lacked detail on the
scripting front, which caused significant confusion amongst
first-time buyers unfamiliar with the SIOC concept. The
chronometer's manual is infinitely better, and should prove
completely understandable to most users.
The chronometer is, without a doubt, the best Opencockpits product I
have reviewed to this date. It is compact, sleek, well-finished,
fully-functional, easy to use and, most importantly, very low priced
in comparison to competing and similar products.
In the past I have made several recommendations in my reviews to
Opencockpits regarding some of their products. The chronometer,
whether through these recommendations or not, represents a huge
improvement and overcomes all of these past problems by a
Very compact and solid feel
Easy to set up
Lovely warm backlighting
Excellent engraving quality
Decimal point used instead of colon for timer display – a very minor
Opencockpits' 737 Chronometer is awarded an overall Mutley’s Hangar score of
with an "Outstanding" and a Mutley's Hangar Gold Award.