ErSky9x Tray Radio - RC Groups
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Jun 24, 2012, 09:51 PM
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Build Log

ErSky9x Tray Radio

This build log is for my project to build a new tray type transmitter using the ErSky9x board, parts salvaged from a JR 388 Transmitter, and parts purchased from various sources but commonly available.

The Er9x Firmware and the Eurgle/Turnigy/iMax 9x Transmitter

I have two Eurgle/Turnigy/iMax/younameitchinese 9x transmitters with Er9x firmware loaded into the Eeprom which runs the logic i.e. programming of the transmitter, as distinct from the Radio Frequency component. I am a fan of the Er9x firmware because it allows unprecedented programming freedom. Anyone who flies a model aircraft, helicopter or quadracopter where multiple inputs affect a control or where multiple outputs are needed from any control will appreciate the virtues of being able to assign any channel from any switch or pot or stick on the transmitter to any servo in the ariel vehicle, apply multiple inputs from any switch, pot or stick to any other servo or number of servos, using almost any set of logical conditions, with delays and slow actuation for any command, and curves with up to 9 points applied to any command. These transmitters use FrSky Telemetry Tx modules and telemetry receivers to display data such as transmitted signal strength, received signal strength, altitude, bearing temperatures, and battery voltages on the transmitter screen. Alarms for low received signal strength, low battery voltage and upper height limit can be set., all using the Er9x firmware.

Er9x home page:
Er9x Wiki page:

SkyNorth Design have have released for sale a replacement motherboard for the Eurgle/etc 9x transmitter which does not require any soldering skill to instal and does everything the highly modified Er9x will do without having to do extensive research, solder finicky tiny pieces of wire onto almost microscopic parts of electronic components or even understand what the electronics actually do. It will handle telemetry for display on the main or auxiliary screen or in future by speech into headphones, allow alarms by buzzer or speech or vibrating (haptic) output, allow uploading and downloading model programs by direct USB connection to a laptop computer or in future by bluetooth from your iPad, phone or other bluetooth device, store hundreds of models on an SD card and of course host Er9x firmware for superbly flexible programming of your models.

It's here:

All of this is supported by the 9x Forum here: where you can get help on any topic. The most important for the ErSky9x motherboard is here: . While this link is on the previous linked page I put it here for ease of reference; it's the primary site for anything ErSky 9x motherboard related.

Now there's months of reading in those links above which I have inexpertly agglomerated into about a years research and development to understand how to modify an Eurgle/etc 9x transmitter. So when SkyNorth, a contributor to the above forum, released the ErSky9x board onto the market I was fascinated by the possibilities and hence this project.

What do you do when you already have two hand held Eurgle/etc 9x radios with FrSky modules, telemetry and more model memories than models? What do you do to keep costs down and use up that old superseded JR 388 transmitter? What do you do when you prefer to fly some models with a tray type transmitter and your old one is over 20 years old? Why; build a new tray type transmitter of course with all the bells and whistles using as many old components and mate them to the new motherboard!

So here's what I have done; I hope it gives you some inspiration. I hope I can complete it successfully

The JR 388 contribution

The JR 388 has the same number of switches and potentiometers and sticks (!) as the Eurgle 9x does.

The insides are similar to the Eurgle 9x with a motherboard, a backboard, and a screen driver board with a switch and buzzer. The first task was to understand what is the function of each board, decide what was redundant and what is useful.

There are two gimbal assemblies with two rotary pot type manual trim levers fitted to each, 5 two position switches, one three position switch, one momentary action switch and three potentiometers. Except for the trim pots and levers this is the same as the Eurgle 9x so all these parts can be used with suitable new harnesses and header plugs to suit the ErSky9x board. New trim pushbuttons or momentary switches will be needed to replace the trim pots and provide trim inputs to the ErSky9x board. There will in future be firmware provisions to allow the connection of 12 or more digital or analogue inputs. So it will be possible to include two trim levers to allow rudder and elevator trim to be set manually. Why? Well I like to set my gliders into a thermal turn using the trims so I don't have to hold the stick with a little side and back offset from neutral. I like to be able to feel where the trims are set rather than take my eyes of the model. It is often the case that the model is hard to see anyway without trying to look down and then looking back try to find it again. (especially when the sky is all blue or white.

Are any of the boards useful? I think the back board may have some use. It has a voltage regulator on it, a fuse for the battery input, and a large space for mounting the Frsky DHT (with Telemetry) 2.4 GHz RF unit which I intend to use. See here:
It has a trainer ports and a charging port; neither of which I have decided I will use.
Last edited by Mutchy; Jun 24, 2012 at 10:25 PM.
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Jun 24, 2012, 10:00 PM
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For a buddy box system I will use this:
because it takes away any compatibility issues between instructor and pupil's radio systems. And it's cheaper than a cable in many cases. It just requires a spare Rx from the Instructor.
For charging I will use a socket in the side of the transmitter case in the same area as all the other sockets will be, to charge the battery using my field charger. It will be two Trustfire LiIon batteries from here:

So what's on this board? It's the one on the left of the picture above. I drew up the circuit diagram below to identify the useful connections to and from this board:
Jun 24, 2012, 10:02 PM
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The pins in the middle of the board are those that any old RF module connect to so this space will be convenient to attach the FrSky DHT module. The three pins I need, Earth, Signal (or PPM), and 6 Volts can be used to solder onto the appropriate leads from the DHT module. This board may be quite useful. More on the battery connection, the use of the regulator, and other parts of this board later when I find out what's on the ErSky 9x board for handling battery in and regulated voltage out.

Of the other boards the only one which may have some use is the board with the switch on it. It also has a small Piezo buzzer. The motherboard will be useless. Both are replaced by the ErSky9x board. Notice that all the connections from the other boards and the switches etc. are all directly soldered onto the JR motherboard! No headers and plugs……. more on those later.
Last edited by Mutchy; Jun 24, 2012 at 10:03 PM. Reason: typo
Jun 24, 2012, 10:04 PM
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I picked up the JayCar catalogue and found a mini Piezo buzzer and an identical DPDT switch for about $6 total for both. It may be more convenient to use them mounted on a piece of veroboard or something similar rather than chop the board about, trace and cut PCB tracks and/or desolder stuff. I'll have a look at that when it's not so cold down in the workshop. More to do on this subject later.

I received the ErSky9x board and it's a lovely piece of craftsmanship. It is the Revision B1 board with two jumpers and the modifications for the power supply to the speaker which also comes with the board. There's a lot of discussion on the forum regarding this which you can therefore ignore.

The headers on the ErSky9x board are JST PH series from here:
These were not available in Australia so I ordered them from Digi-Key. Don't forget to order the crimps which go inside the housings.

Here are the useful parts I have at 24th June:
Last edited by Mutchy; Jun 24, 2012 at 10:22 PM.
Jun 24, 2012, 10:08 PM
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The gimbals have the trims attached. It is a simple job to unscrew the trim lever assemblies from the sides of the gimbals as shown below: They can be used as stand alone rotary potentiometer inputs for things other than trims i.e. flaps, undercarriage doors, the ratio of coupled rudder to ailerons travel……

There is a lot more to do to figure out what is needed and more searching through the forum to understand what I need to assemble the basic ErSky9x radio. I need to move to the case design. I am sure I will find more questions than answers as I develop the case layout and clarify my thoughts.
Last edited by Mutchy; Jun 24, 2012 at 10:09 PM. Reason: typo
Jun 24, 2012, 10:11 PM
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The case design and development

I have an ancient Robbe/Futaba FC 28 which now runs an FrSky 2.4 GHz module. I use it mainly for flying F5B gliders (hotliners) and have in the past used it for F3A aerobatic planes. It was very difficult to learn to program but it was very advanced compared to it's contemporaries; and also quite expensive. It allowed four flight modes at a time when the mainstream didn't even recognise flight mode programming. It is big and together with it's tray is quite heavy; built like a brick dunny. I used it and it's case as my guide for the design. You can see it behind my mockup in the next photo. My resources are limited to hand tools mainly so there won'y be any NC machined Magnesium case. I decided to use fibreglass mouldings for the top and bottom. I have moulded fuselages, spinners and propellors so I have some experience.
Last edited by Mutchy; Jun 24, 2012 at 10:12 PM. Reason: typo
Jun 24, 2012, 10:14 PM
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The Ersky9x board will in future support an additional screen (here: ) which I have allowed for in the layout of the front face. Unfortunately the multicore ribbon from the screen is only about 60 mm long and unless I can find an extension lead cheaper than the one I found at US $38 I will swop it's allowed position with the speaker. It may have to come down to just above the ERSky9x board which you can see in outline at the bottom. I am not sure that the additional screen will be useful in flight but it will be more useful if it's at the top of the Tx than down near the other one where it will tend to get lost. I have signal strength temperature and battery voltage telemetry on my Er9x transmitter for my ancient but newly converted to electric F3A model and never look at the screen during flight. It's very handy after landing though to review the figures.

I have allowed for two of the trim levers to be positioned inside of the gimbals. I am considering how important it is to me to have the an allowance for the other two trim levers above or below the gimbals the left one of which would allow for my style of thermal soaring. I am just talking about an allowance at present until firmware is developed for the extra I/O. I have incorporated momentary buttons in a cross formation below the gimbals for digital trim operation, like the Jeti DS - 16. The three switches above each gimbal are spaced along the locus of one's fingertips when holding the sticks. Operation of the pots above the switches requires lifting one's hands off the sticks. The switches to the inside and lower than the gimbals are convenient for thumb operation which is also the case for the trim buttons. The smudges in the lower corners are for the neck strap or harness collapsible support frame similar to the FC - 28.

There is a wide groove on the bottom of the case running vertically under the "wings" which support one's hands. This groove allows a comfortable and safe grip if one wants to pick it up by the side. The antenna is intended to be mounted from the top face and be unscrewed when stored in it's aluminium carrying case. Because the case is not metallic I have in mind to do some range experiments with the antenna mounted inside the case, maybe along the top corner…… A long way to go yet before I do that!

There will be strengthening ribs along the inside of the flat bottom to stiffen this surface and maybe some grooves for the hand rests on top of the wings. This allows air circulation under one's hands, and a cooler support during summer.
Jun 24, 2012, 10:19 PM
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Here's the Jeti DS - 16 - well, one of the three or four different control layouts I have seen:

There will of course be an additional tray for the DS - 16 to sit in from Jeti and the aftermarket to suit individual taste and comfort. My tray is moulded integral with the Tx .

The next step is to make the same thing out of Craftwood, a composite non porous timber of uniform consistency which can be finished to a smooth polished surface suitable for taking moulds, top and bottom. But I'll think some more about the layout first, source some momentary switches and think about the internals. I am not sure where the buzzer board fits in nor where the battery supply comes from so I have to take one of my Eurgles apart and have a look.

So that's where I am up to. Any suggestions welcomed. Any information or clarification gladly received or provided.

More Anon
Jul 03, 2012, 07:53 AM
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The plug for making the top and bottom moulds is under way. The material is MDF. The main body of the Tx is four laminates of 12 mm thick board. The parting line, or if you like the join between the top and bottom halves of the Tx will be 12 mm down from the top. The top part of the Tx will have a flange about 10 mm deep which will fit inside the bottom half and take the screws which will secure the top to the bottom. The top and bottom have a slight draft so that when the mould is made the sides are not vertical. This helps to ensure that the moulded part does not jam inside the mould.
Some 1000 words follow but here are some more: The triangular section sloping part of the Tx top is being glued to the top laminate. The top and bottom parts of the plug which are doweled together are already trimmed and sanded to size and shape. The smudge is where a label has been removed and the cleaning solvent has not yet evaporated.
Obviously some corners need to be rounded off. I am not sure about whether to bevel the top surface edges or round them....
Jul 16, 2012, 06:28 PM
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Ricardo Trevisan's Avatar
I am also having the same purpose, use the board ERSKY9X, two internal modules FRSKY, and these sticks aurora and other high quality components and keys potenciomentros even here in Brazil. But I'm checking how the shell of carbon fiber and aluminum, have to do for now make parts and molds of the same .....
The part of the high place the way it would display FrSKY easy to verify telemetry. I really enjoyed your monde is well thought out, which will be ready with his weight battery.

Sorry English is not usual here.
Jul 17, 2012, 06:57 AM
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Thanks for your comment, Ricardo.
I have made some more progress with the plug for the mould. I have bought a machine to help me to form the shape of the plug. First I had to learn how to use it and this took some time.
Here are some pictures taken today.
Jul 17, 2012, 07:16 AM
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cr8tive_leo's Avatar
I''ve been following this thread since it started, all I have to say is, outstanding!

I too have started to redesign a tray type controller to stick the er9x guts in... but with a few other twists. 7 inch daylight colour touch screen with hdi, vga and 2 composite inputs for fpv, installation of a raspberry pi .

I love the form of your tray! Wish I had more time to complete my project. Excellent job again!

Routers are extremely useful, you can create all sorts of wonderful channels and bevels on plugs. You can mount it upside down on a router table, may be easier to use than to hold it by hand. (I just cut a hole in a table and mounted it there, with a few adjustments, it works wonderfully)
Jul 17, 2012, 06:53 PM
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wow this looks great!
I was thinking about something similar but it seems to me many people around the world are willing to make their own tx. And I have to admit I love this craftman approach!
I tought about a musch simpler design, no round edges, tray stile with integrated tray like yours, aurora gimbals, display in upper position.....wiat it's what you're doing and everybody else is doing...sound like there's the need for a good and cheap tray tx!
thread subscribed, gonna follow your work and copy some ideas, ah ah!
Jul 17, 2012, 07:45 PM
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Ricardo Trevisan's Avatar
OK I really liked your project ........

But I will make it a radio, with ergometry .... perfect .... keys within easy reach and a very good support in the sticks ... to put it here in the forum in Brazil a question ....

What is the correct way to hold the sticks the Radio?

well with an idea of what I'm searching, and I want a radio that you can use for a long time .....

I'm following the project ..... congratulations .....
Jul 18, 2012, 03:52 AM
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Mutchy's Avatar
Originally Posted by cr8tive_leo
I''ve been following this thread since it started, all I have to say is, outstanding!

I too have started to redesign a tray type controller to stick the er9x guts in... but with a few other twists. 7 inch daylight colour touch screen with hdi, vga and 2 composite inputs for fpv, installation of a raspberry pi .

I love the form of your tray! Wish I had more time to complete my project. Excellent job again!

Routers are extremely useful, you can create all sorts of wonderful channels and bevels on plugs. You can mount it upside down on a router table, may be easier to use than to hold it by hand. (I just cut a hole in a table and mounted it there, with a few adjustments, it works wonderfully)
Hi Leo
Thanks for dropping by and thanks for the compliments. I have used the table for the grooves underneath the plug and I did the rounded edges freestyle using a router tool with a small wheel (a bearing actually) on the end. Next step is to use templates for the screen aperture and stick apertures.

I am impressed with your goal of adding all those extra features to the Er9x. The raspberry pi, I hope, is something technical and is not the one I am familiar with.... $2.20 from the patisserie


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