X9e SmartPult

I like the X9e because its case is so articulated and easy to maintain. Therefore it is particularly well suited for extensions and other handicrafts. But a few little things already bother me. For example, the weak plastic straps that do not keep the transmitter well balanced. So buy the CNC temples and retrofit? Also, the space is tight to install other extensions as a simple switch. That's why I came up with the idea of building a kind of transmitter tray that meets as many of my requirements as possible.


The name "X9e SmartPult" derives from the German term Senderpult, which means transmitter tray.


First of all, I put together all my requirements:

  •      a stable hanger that is better balanced
  •      with hand restraints that make all joysticks ergonomically accessible
  •      the transmitter should continue to fit in the original bag
  •      additional input devices via Arduino to DSC (see here)
  •      two plug-in and interchangeable (and thus model-specific) modules for the input devices
  •      all original input devices are retained and usable (also the lateral sliders)
  •      DSC socket still usable for trainer mode if required
  •      all sockets and plugs should remain accessible and usable (including additional module antenna)
  •      the housing bottom should remain easily removable in order to get to the inside
  •      an additional holder for screen mounts or similar ("future use")
  •      as little intervention or changes to the housing as possible (for a trace-free removal if necessary)


A smart transmitter tray "SmartPult"

I would like to present the result of my tinkering at this point and maybe lead one or the other interested parties to replicate.

Fortunately, I was able to fulfill all my above requirements largely. Actually, it is not a "tray", but two laterally fixed extensions. Each of these enhancements features an Arduino Nano that provides eight analog inputs for each of the pots, switches, and so forth. The electronics and programming for this I have presented here. You could also simplify the whole thing by using only one Arduino and distributing the eight ports on both sides. But even a single joystick with button function already consumes three of these inputs and you would be pretty fast on the limit.

The two extensions are attached on both sides to the three original fittings of the series hand rest. The only change to the housing is a hole for cable glands, which are closed in a potential dismantling by the series hand restraints. The sides of the transmitter housing are not exactly vertical, but inclined inwardly at a shallow angle. I have simply ignored this in favor of a simple design, which is why the hand rest of the extensions is not exactly horizontal, but increases slightly to the outside. But you have to look closely to notice, and in the use it does not bother in my opinion.

The electronics are connected to the mainboard and switched on and off with the transmitter. Very important is the protection of the transmitter electronics by an intermediate fine fuse of about 500 mA. I destroyed my mainboard due to an accidental short circuit in one of the modules and had to install a spare part for 90, - € !!! (Therefore at this point again the note: all copies and interventions in the transmitter electronics are at your own risk and on your own responsibility, I can not and do not want to take any guarantees or warranty.)

In addition, you can turn off the extension separately via its own toggle switch. With a power consumption of the two Arduinos of not inconsiderable 500 mA (measured) you can save a lot of battery capacity here when not in use. In addition, since the DSC socket remains free and usable, you can easily switch off the extension as needed and use the trainer mode.

Only three wires are connected to the transmitter electronics: Ground and supply voltage on the mainboard and the cable to the DSC socket.

Before the details here are some pictures in advance:


The construction is not that difficult. Although I have created most of the items with my cheap China CNC milling machine, they can certainly be made by hand with manageable effort.

In the download below, I have collected together various 2D drawings created with LibreCAD that contain all the required parts. However, I recommend that you only use them as a template, as some dimensions depend on, among other things, the thickness of the materials used.


For my specimen, I used the following materials:

  • Carbon fiber plate 2 mm (top plate and hanger and small parts)
  • black fibre plate 2 mm (inside and bottoms)
  • Alu Dibond plate "Butler Finish" 3 mm (module plates)
  • Plywood 3 mm (other housing walls)
  • Beechwood strip 8mm (corner connector of the housing)
  • board material

1. The insides


The side panels are important because they represent the connection to the transmitter. In the photo you can see the three smallest holes, which correspond exactly to the fittings of the serial hand rest. Here you have to work carefully. You also have to position the V-shaped recess at the top, which later provides space for the slider.

The two vertical recesses are used for precise positioning and tapping of the housing side parts.

The upper, front hole serves as a receptacle for the sleeve rivets as the axis of the carrying hanger. You can see the outer recess to sink the edge of the rivet later. This is also the only detail where the left and right inside are different.

Finally, the last and largest bore is the later cable entry into the housing.

Before building the housings, the two side parts should be screwed once to the housing and the holes for the cables drilled in the transmitter housing. For this purpose, a step drill is particularly well suited as seen in the pictures below. This can be very well centered and drills very clean holes.

Caution: During this step, of course, you must be very careful not to drill too deep and damage any parts of the transmitter, the gimbals or their leads. Therefore, this step should only be carried out with the transmitter floor removed. In addition, the holders with the three threads inserted on the inside of the transmitter should be removed as soon as the step drill drills the smallest step into these parts. The further steps to the desired size can now drill much safer outside the transmitter in these parts.

For weight reasons, whoever likes to disassemble and remove the original transmitter mounts that are no longer needed from the transmitter base. These can be re-assembled if needed later.

The following pictures illustrate these steps.


2. The basic housing


The basic housing is a simple rectangular box made of plywood, which is glued to the side panels. I used super glue for this, which is sufficient for this purpose. Before bonding, smooth surfaces such as GRP sheets should be roughened.


The bottom plate should be used with a separating layer that protects against unwanted adhesion (I would like to use a clingfilm) to achieve clean right angles and high accuracy of fit.



The six corner connectors made of beech wood, assumes in addition to the reinforcement of the housing other tasks:

  1. they allow the rounding of the outer edges
  2. they pick up the screws of the bottom plates
  3. a 1 mm deep recess on the top compensates the higher board thickness of the Dibond, so that the modules can be inserted flush
  4. a 2-3 mm deep recess on the bottom serves as a central location for the electronics, which are held in place by the bottom plate of the case.

After bonding, the holes for the fixing screws of the floors are pre-drilled and hardened with a little instant glue. Later you can round off the outside of the case a bit and paint as desired or dress with foil.

3. The top plate and hanger

The top plates and hangers mainly determine the later appearance of the finished tray. That's why I opted for expensive carbon fiber plates, because I like their appearance, they fit well with the X9e design and carbon fiber feels - I think - very pleasant. In addition, it is particularly well suited for the hangers because of its stability.


Of course, the dimensions of the top must fit as closely as possible to the rest of the housing. First there is the recess for the slider, which must be positioned exactly. Also, the slot on the front edge must fit exactly to the side part, so that the hanger can rotate later through the slot around its axis and can fold down. And last but not least, the large recess for the modules is important because it determines the later position of the modules.

The projection with the slot at the rear end is not so important. It is intended as a potential inclusion for further enhancements such as a screen mount or the like.


The carbon fiber parts are glued with Uhu Endfest 300 or a comparable epoxy adhesive and optimally tempered at 70 degrees for 45 minutes in the oven. Before bonding, all contact surfaces should be roughened by sanding. This results in a heavy-duty connection in a relatively short time.

It is recommended that this bonding be carried out in two steps for the sake of simplicity. In the first step, the two tops are glued to the housings. Make sure that the outer edges of the GRP inner sides and the upper side as well as the respective cut-outs for the sliders are exactly flush. With the remaining adhesive, the two brackets for the hanger and the future screen holder are prepared from the eight small carbon fiber parts as shown in the picture on the left. When mounting the bracket for the hanger, make sure to create one right and one left side each. These assemblies are now tempered.


In the second step, the four newly prepared brackets are glued to the cutouts of the top side glued to the GRP insides. By inserting the later serving as an axle tubular rivets is thereby ensured that the corresponding holes are exactly above each other. Finally, heat again for another 45 minutes at 70 degrees in the oven.

The pictures below show the pre-glued brackets and the housings with inserted hanger. I have used rubber rings in the carrying strap holders of the retaining clips, which are actually intended to protect cables in sharp-edged housing openings. They are intended to prevent the metal fittings of the carrying belt from grinding black coal dust permanently during use.


4. Electronics


The boards are completely identical on both sides and each consist of two interconnected sub-boards. The reason for this is the license of the layout software Eagle, which limits the boards in the free Light variant to a maximum size of 100 x 80 mm. With Eagle, the actual circuit was created, which includes the Arduino Nano and the other components. The extension to accommodate the modules was drawn with LibreCad, since it comes here anyway rather on the exact positioning of the jacks.

I also made the Eagle boards with my CNC router and had a number of problems, so the final results were of poor quality. With a few additional cables I was able to save them. But I think that you can build the very simple circuits also very well on breadboard maps manually. One should only make sure that the finished boards fit exactly into the recesses of the housing, so that later the modules can be plugged.

A detailed description of the circuit as well as the Eagle files for the first part are available here, the CAD files for the second part are available in the downloads below.


5. Wiring and connection to the X9e

For the power supply we can use the unused port P12 located on the motherboard between the plug of the charging socket and the battery. Of the four poles, the leftmost one (immediately next to the imprint "P12") provides the GND and the one next to it the battery voltage when the transmitter is switched on. Caution: A short circuit between these two poles destroys the mainboard when the transmitter is switched on! For this reason, a fine-wire fuse of around 500 mA should be inserted into the positive cable immediately behind the connector.

The pin distance is 2 mm and since we only need 2 poles, you can very nicely use a similar, reverse polarity protected three-pole socket as on the switchboard of the transmitter (type JST 2.0 PH). Below pictures show the P12, where you can still see the tin residues on my old mainboard on the first picture, to which I had initially soldered the lines directly. On the second and third picture you can see below the connector also the black heat shrink tubing in which the directly soldered fuse resides.


The only other connection to the transmitter electronics is a signal line to the trainer / student jack, which is located on the switchboard.

On the photo next to it you can see to which pin you can solder the wire (here in green).

The following pictures show the complete wiring as a photo and schematic representation:


6. The modules


The modules are actually just the front panel and two small boards that are glued vertically and stabilized with a few small triangles. For optical reasons, I opted for Dibond plates in the "Butler Finish" design.

The two boards establish the electrical connection via two angled pin headers and provide contact surfaces for connecting the input devices. If, as here, electrically conductive materials are used for the front panels, it is of course necessary to ensure insulation of the contact surfaces of the terminal boards.

When manufacturing the modules, you first work on the front panels and prepare all required holes etc. for the input devices. Helpful for the stability are also milled grooves into the bottom of the front panels for receiving the boards. The parts are glued again with Uhu Endfest 300 and subsequent tempering (again 45 minutes at 70 degrees).

In order to bond the modules straight and fitting to the housing, I have created a simple subframe of 4 mm plywood and two boards whose dimensions correspond to those of the housing. The necessary parts for this are also available in the download of the Libre CAD drawings.

After gluing, the input devices such as pots or joysticks are installed and then wired to the side boards. The four inner pads are input ports, the two outer pads are GND and V +.

Basically, no contact surfaces should remain open, as this leads to unpredictable states of the corresponding ports. If a port is not needed, it can simply be shorted to ground and thus receive a defined state.

The following gallery shows different sections of module creation. The modules shown here are intended for a fire-fighting boat "Düsseldorf". The fire-fighting guns should be controlled with the two joysticks and switched on and off via the integrated button. With the potentiometer the crane should be turned proportionally, the middle switches should control the crane motor and the windlass. The three lower switches are not yet planned.



A few notes about the downloads:

I've tried to work in LibreCad with layers separated by milling tools. The white layer "0" represents the real contours of the objects and is the essential information.

All other levels include the milling lines with integrated tool compensation. The name of the layer includes the diameter of the intended milling cutter. This allows the simple creation of separate, tool-separated milling files if required.

Attention: The milling depth was not considered in the files. It is therefore important to ensure that the milling depths that are not completely milled are set by the reduced milling depth itself. This applies, for example, to the side parts for the outer ring of the rivet axes, which are intended to allow only the flush countersinking of the rivets. Also, the slots for the boards in the module front panels should of course only be milled on the undersides and not be throughout.

The front panels of the Dusseldorf I have also included as an example, since the joystick modules used are not symmetrical and therefore were not easy to measure. If you also want to use such modules, the information may be helpful ...


X9e SmartPult Downloads.zip
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