The FWD and AFT Overhead are together equipped with 8 meters or ‘gauges’:

  • Fuel Temp
  • EGT
  • Diff Press and Cabin Alt
  • Cabin Climb
  • Temp
  • Duct Press
  • Valve
  • Oxy Press

The complete description and features of these gauges are to be found in the different Boeing 737 manuals found on the Internet.

Like the gauges in the MIP, I have the OVH gauges also purchased at Custom Sim Parts.




In the world of the cockpitbouw we can say that Flight Illusion about the market leader in the supply of meters, clocks, or gauges. This company has also a large assortment available for anyone to his liking in can find.
The gauges of FI are made with quality materials and nicely finished. The drive of the FI gauges is done with steppermotoren.

A few drawbacks are that the FI gauges are quite expensive, not always easy to configure, and no realistic backlighting.
There is a small led on the front of the front plate that the front is lit, some of the FI gauges are equipped with a FLUORESCENT-type white led (Ice white or keukenlicht). There was no question of ‘backlighting’...

FI Flaps

Coincidentally, via the Prosim737 forum, I ended up with Custom Sim Parts. This company also makes gauges but for the time being to a limited extent. At the time of this writing that only the B737 MIP gauges such as Flaps, Brake Pressure, Yaw Damper, and all B737-Overhead gauges.


What do the gauges of Custom Sim Parts so interesting :

  • Cheap;
  • All gauges can be custom-made to be made according to the wishes of the customer;
  • The backlighting is very realistic and beautiful;
  • Very simple installation and easy configuration;
  • Can be used with the Pokeys Microcontrollers + Led extension board and Prosim737 for a realistic backlight control.

When the first contacts with Custom Sim Parts is asked the size (diameter) of the gauge openings in the MIP or Overhead. This, together with the dimensions between the various boutgaatjes that the gauge must be confirmed.
To the size extra to clarify, one can also some close-up photos of the front and rear of the Overhead join.



On critical places where few or not enough space, due to the presence of a switch or a circuit board, then you can always try to find a solution, for example, the gauge may be smaller or in a different shape (e.g. diamond).
Afterwards, you will receive Custom Sim Parts of a drawing with the proposed desired dimensions for approval.

Here is an example of CSP with proposed dimensions:

FlyEngravity OVH gauges dimensions

These drawings print/cut I from true to size to fit in the Overhead. The circle of the gauge should fit with the opening in the OVH, together with the openings for the bevestigingsboutjes.

If the gauge openings in the MIP and OVH are equipped with a glass one can also the CSP-gauges ordering without glass on the front.

The control of the gauges is done using standard digital servos and this together with a Pololu Servo Controller. There are 2 versions :

The 6-Channel version is usually used for the MIP and the 12-Channel for the Overhead.

With the 12-Channel controller, one can, if necessary, MIP+OVH together, connect only the distance OVH>MIP to the Flaps and Brake Pressure gauge can be an obstacle ...
Therefore, it is easier for the MIP and OVH separate controller to use.
The remaining free ports on the controller can still be used for digital Inputs/Outputs. Unfortunately Prosim737 is not compatible with this Input/Output channels. Only the Servo channels will be recognized by Prosim737. That is a bit of a pity ...

This Pololu Servo Controllers are fully assembled. They are very small (30 mm x 20 mm) and are so easy to work behind the Mip or in the OVH.

The backlighting is done via an led (20 mA) which is behind the front plate is installed. The colour of the backlight can be choose, and is therefore optional.
The standard ‘warm white’. But one can also opt for an Amber-colour.


My FlyEngravity MIP and OVH-panels are all equipped with a warm-white backlighting. This is why I have opted for ‘warm-white’ as the backlighting for the MIP and OVH gauges.

The backlighting may be powered via the Pololu-controller port with a supplied splitter cable.
It is also possible for the backlighting to focus on more realistic ways (see separate chapter below).




Gauges can be powered with servos or steppermotoren. Both ways have their advantages and disadvantages.



The gauges of the Custom Sim Parts are equipped with digital RC servo's. Why?

  • Servos are much easier to implement than a stepper motor and much cheaper;
  • They can be connected to any standard servo controller what the gauges are universal or generally applicable make;
  • Servo-controllers are very cheap and there is a lot of choice in;
  • In the trade it is not easy to find a combination of a steppermotor with a controller at a similar price as in servo controller.



Which components have we all need to have the CSP gauges to install :

All cables and connectors are free of charge included (except the USB cable) 🙂. The cables and connectors are also ‘custom-made’ i.e. that I own the dimensions and lengths determined have of the different cables. They are me neatly sent as I had requested and without any extra cost.



The installation of the gauges in the housing of the Overhead is quite easy. Of course the holes for the mounting bolts match the holes in the gauges.
Therefore, it is very important before the correct dimensions to pass on to CSP.

Also the dimensions for the gauge itself are important, i.e. the diameter of the opening in the ‘Overhead’ and the max size of the perimeter of a gauge. As with an ICS system is the ‘Overhead’ full of printed circuit boards (pcb’s) and it is sometimes tight on space for a gauge to be able to places.

According to the wishes of the customer, CSP the gauges to adjust in size, and according to the desired dimensions. Even the circle of some of the gauges I have let move to the left or right in the housing of the gauge.

I have e.g. also asked for some changes to the front regarding the color:

  • EGT - gauge > text “°C x 100” in blue color;
  • Cabin Climb gauge > text “1000FT PER MIN” in blue color.

So everything is possible ...

The confirmation of a gauge is carried out with 2 bolts each 4 mm thick (4M) and a length of 25 mm. The bolts I painted in Boeinggrijs.

Note. During the confirmation of the Temp gauge I may experience that the orifices for fastening to the wrong side were made. I have this error also reported to CSP. Two weeks later there was a new gauge in the brievenbuis with the holes in the right place. Top service! And to err is human ...



1. Install the Pololu drivers with the "Maestro Control Center":

Maestro Servo Controller Windows Drivers and Software (release 130422) (5MB zip)
This ZIP-archive contains the installation files for the Pololu Controller with the Maestro Control Center, the Maestro Command-Line utility and the Pololu Maestro Servo Controller-drivers for Windows.

2. Connecting the Pololu Servo Controller with the USB cable:

The Pololu Servo Controller should be connected to the pc where Prosim737 is installed. This happens with a USB Mini connection cable
(USB A, male <=>USB B, male 5-pin 3m).

This usb cable I have purchased from Allekabels.nl. The cable of 3m, I have the hollow metal frame of the cockpit, pulled up in the cabinet of the Fwd Overhead. The Pololu Servo Controller I have above in the case of the Fwd Overhead confirmed. This Pololu Servo Controller is very small and can be easily somewhere in the Overheadbehuizing be placed.


3. Verify in "device Manager" in the Pololu USB Controller is installed:

CSP-Device Manager

4. Connect the servos of the gauges (and backlighting) with the controller:

Option 1 > The gauge is equipped with 2 small books cables : cables that come out of the servo and a bundle for the backlighting.
Both are with a splitter cable connected to the controller.

This option is the backlighting only directly controlled by the micro controller and not by Prosim737. When the Pololu micro controller under voltage state will also be the backlighting of the gauges start to burn or to light. In a Cold&Dark cockpit, this is so not realistic. The use of a tussenschakelaar in the cockpit can hereby offer a solution.


Option 2 > In the gauges of my OVH remain the separate connections for the servos and backlighting separated. On the back of the gauge is equipped with 2 pins for the backlighting (not standard). On these 2 pins is there a verlengdraad (extension) is connected on the other side is connected to the Pokeys Led Extension Board. Further explanation about this connection in a subsequent chapter.

For the servo's can take 3 (short) wires with connector at the end. These are also extension cords (extensions) connected to cover the distance between gauge(servo) and the Pololu Controller (this is on request of the customer).

When this option is selected, the backlighting is completely controlled by Prosim737 and this by making use of the Pokeys Led Extension Board and a Prosim gate ‘AC Power’. The set-up of AC Power (Gnd Pwr, APU, Generators) is the backlighting of the gauges will also be active.


The flat plugs or connectors for the servos include 3 threaded ports : 1 white for the signal and the two others for the + (red) and – (black).
The blue jumper is placed like on the images.

5. Connecting the controller with the 5V power supply

The 5V power supply one can get from an old pc power supply. Usually it is a homecockpit already equipped with such a’Power Supply’-container and can we have somewhere to drain. The flat plug for the controller has 2 terminals, + and – . The third is not used.

See pictures for the correct connection.



6. Open Maestro Control Center and make sure the controller is connected ("Connected to" followed by the correct card number).

7. Select the assigned channels in (0-1-2-3-4-5-6-7-8-9) by placing a tick in the check box (enabled);
Note. The ‘Diff Press’ and ‘Duct Press’-gauges have a double servo.

8. Make sure to test the servo by moving the sliders with the green dot. The pointer of the gauge together with the slider to move;


9. Go to the ‘Channel Settings’ tab;

10. Fill in each channel with the names of the gauges and turn on all the channels in the ‘acceleration’ on 1 (this should to the needles or pointers of the gauges easier to move);

11. Click ‘Apply Settings’ and close the program.




12. Start Prosim737;

13. Open Configuration/Drivers;

14. Enable Pololu support by placing a checkmark;


15. Go to the Gauges tab;

16. Scroll down to the correct gauge;

17. Choose the correct Maestro Controller in the drop-down list;

18. Choose the Pololu channel to which the gauge is connected;

19. To configure the sliders the correct setting of the gauge and press the OK button;


20. Open Flight Simulator and do a test. Make necessary corrections if needed.




As the connections of the backlighting above in Option 1 and plug the power cord into the wall outlet, then lights up the backlighting of all the gauges. Not a real Cold&Dark situation, and therefore also not realistic ...

The backlighting would, according to the Boeing manuals only active may be when the cockpit under AC power. This is after setting up the Ground Power, APU or active Generators.

How can we simulate it with the CSP-gauges and what are the possibilities?

  • Connect the backlighting of the gauges directly to 5V and place a switch in between. When the cockpit is switching to AC power, turn the switch on;
  • Linked to the switch from the ‘Ground Power’ (via a low voltage – high resistance – reed relay with a separate circuit from 5V or 12V). When the switch of the ‘Ground Power’ is used the relay to On/Off and backlighting switch.
    But then one is dependent on only the ‘Ground Power’ ...
  • A relay card with digital Outputs and compatible with Prosim737. In the Prosim737 configuration is a ‘Gate’ is used;
  • The use of Output channels in the Pololu Maestro Controller and link it to a ‘Gate’ in Prosim737 (as mentioned in previous).
    Unfortunately, this is not possible since Prosim737 is not compatible with the In/Output channels of the Pololu Controller. At the time of this writing, Prosim737 only to be used with the Pololu servo channels;
  • The use of a Pokeys Microcontroller and a corresponding ‘Led extension board". In the Prosim737 configuration is a ‘Gate’ is used.
    Since I'm one of the (first) users of the Pokeys card and the Led extension board " I have this option also be investigated together with Custom Sim Parts and FlightSimParts.eu (Wendy).
    After some testing I found this is the right, easiest and cheapest solution to the backlighting realistic.

Control of the backlighting through the Pokeys Microcontroller, Led extension board and Prosim737

Here follows a step by step approach to the Pokeys, the led extension board and Prosim737 to be configured so that the backlighting of the gauges starts to light up when switching on AC power:

  • The OVH gauges are at the rear equipped with 2 pins for connecting the backlighting (not standard).
    Since the backlighting is separately connected to the Pokeys and the Pokeys Led Extension Board has one so each gauge has 2 pins. It facilitates the connection because it is the length of the wires themselves can determine and the (-) and (+) of each other can separate. Corresponding cables with connectors (extensions) are included in delivery. The customer determines the length of the cables.
    To bridge the gap between the cabinet of the Overhead and the Pokeys Led Extension Board (rear MIP), I have a cable pulled through the tubes of the hollow metal cockpitframe.
    The cable is on the inside, composed of 8 wires. Just enough for 8 gauges ... And the different colors of the wires can serve as guide to which wire is connected to what.
  • Connect one end of the extensiondraad+connectors to the 2 pins of the gauge. (Later in the test may be that the backlighting is not working. Should the threads just be swapped from place to place). The left pin is (+) and right pin is (-).
  • Connect the (+) wires of the backlighting in parallel with each other and connects the latter to the common (+) of the Led extension board". The joint connections of the (+) wires are made with terminals.
  • Then connect the (-) wires of the backlighting, one by one to a separate wire of the cable. This connection I have established, first by the wire of the network cable to strip and then folds. The folded back portion in the connector pressing of the gauge. To do everything to shield and protect, I have a heat shrink over it pulled.
  • On the other side of the cable, each wire separately connected to a free port on the Led extension board".
    (The Led extension board is divided in 2 parts : one half is where the leds are connected, and the other half where the connection to the Pokeyskaart).
    (On the led extension board can be one per port, several leds, and connecting this to max 300 mA. The CSP-gauge is equipped with a led of 20 mA. The backlighting of different gauges can thus possibly be jointly connected to a single port).
  • Then create a connection between a random port on the Pokeys Microcontroller to a port on the Pokeyszijde of the Led extension board". This port is opposite the port where we Ledverbinding have made (e.g. Port 8 to the ledzijde = Port 8 to the Pokeyszijde);Pokeys setup
  • Activate in the Pokeys configuration software (Poscope) the appropriate ports as a digital Output (in our example, Ports 4 t/m 11);
  • Then we open Prosim737 – Configuartion – Gates, and we choose in the list ‘AC Power’ with out the correct Pokeyskaartnr and the correct port.
    To add an extra line to ‘AC Power’ we print the +sign.
    Note. Do not forget that it's also possibly the gauges of the MIP assist (flaps, brake pressure, yaw damper).

When we now have the cockpit under AC Power (e.g. Ground Power, APU, or generators) is the backlightverlichting of the gauges light up.



The prices of the Custom Sim Parts-gauges are very inexpensive.

Custom Sim Parts is very flexible and customer-friendly. The gauges are made according to the wishes of the customer.

For difficult setups and connectivity solutions are sought.

The lead time of 3 to 4 weeks for the build of the gauges and the sending of the order will be respected.

The gauges of CSP are beautiful and nicely finished. The openings for the bevestigingsboutjes sit in the right place, as provided on the drawings and where the confirm runs very smoothly. Ditto for the different connections.
Any errors will be promptly answered by the sending of a new copy.

When they get to the configuration step-by-step photos/videos to follow, this is an easy and simple task. A piece of cake ...

The backlighting of the gauges is realistic and wonderful to watch.

The needles or pointers of the gauges move quickly and smoothly without shock.

The contacts with the Custom Sim Parts (Tom Kaminski) are smooth and fast. Tom is very helpful for giving advice or seeking solutions.
Emails within 24Hr to answer.

The durability of the gauges is not to determine because of the recent commissioning and the advent of the new Custom Sim Parts as a company.

Definitely recommended!





Translated by Yandex.Translate and Global Translator