The idea of this thread is for people to document how they hacked their Tx to 2.4 GHz using the Assan X8D hack module, so others who want to hack the same Tx can see what you did/learned.

The idea is to post:

• Your Tx model
• Where the wires connect to (ie where you cut the existing wires, what colour to what colour etc)
• How/where you mounted the 2.4 Ghz module
• How/where you mounted the antenna
• Any other mods – eg moving the LED so it can be seen, keeping both the 27/35/36/40 MHz module and the 2.4 GHz module, circuit diagrams if you put a switch in etc

Lots of photos please!

Note it is not intended for this thread to be a discussion about performance of the Assan system – for that please see:
https://www.rcgroups.com/forums/showthread.php?t=723343

Also the following threads may be of interest:

Threads on hacking radios using the 2.4 GHz module out of a DX6 (ie the original one, not the Dx6i)
https://www.rcgroups.com/forums/showthread.php?t=458314
https://www.rcgroups.com/forums/showthread.php?t=546434

Article on hacking Graupner MX 16 (JR 2610/2106?) – in French, but good clear photos so you can work out what is going on.
http://www.heli4.com/article558.html

The key dimensions for the hack module are 13mm x 35mm x 55mm. The 55mm does not include the antenna connection - it is about 10mm long, but you also need to allow for the space the antenna will take when it is screwed on. Antenna connection cord is around 20cm long.

Photo below shows what you get in the pack:

• 2.4 GHz Radio Frequency (RF) module
• Antenna connection lead
• Antenna
• Bind plug for 4 channel Rx’s (note there is a different bind plug for 4 channel and 6 channel Rx’s)
• Rx brownout prevention capacitor (4700 uF 10V). You can make these yourself very easily.
• Generic instruction sheet, which has how to bind the system etc but no specifics on how to hack the module into a Rx

The RF module has 3 wires to connect – ground, +ive and PPM signal. A sticker on the module shows which is which. You then also need to connect the antenna (wither directly to the RF module or via the extension lead provided).

There is also a 2-colour LED on the RF module. This tells you that the module is on and ready to use, and also has a rapid blinking rate for binding.

When binding, the Tx and Rx actually “talk” to each other to confirm the bind (ie the Rx actually transmits) – and then the LED’s on both the Tx and Rx change to show successful biding

The following is how I hacked my JR 2610. I wanted to achieve the following:

• If possible keep the 36 MHz module as well as installing the 2.4 GHz module
• Have a switch so I could select the one I am using, and disable the other
• Use a slide switch so it could not easily be accidentally knocked during flight leading to a regrettable moment
• Have the LED where it could be seen easily

Step 1 – Open the Case and Find the Connection Points

First step was to open the case, work out what wires I was going to need to cut and ponder what was going to go where.
The RF board has 3 wires from the main Tx board – ground, power and PPM signal. To work out which was which, I put the black probe from my volt metre on the battery negative and measured voltages – 0V (that would be the earth), 0.7 V (PPM) and 10.3 V (power).

The power was red, the other two both white – so I marked the PPM wire with a red marker so I did not get them confused once I cut them.

Next I trial fitted the 2.4 GHz RF module in various place to try and work out where could get it to go. While it is small, there is not much spare space in the Tx case.

Originally I was hoping I could put the 2.4 GHz RF module under 36 MHz one, but there wasn’t enough room.

I found that there was enough space above one of the gimbals for the RF module to fit (see photos). As part of locating the RF module, I made sure that there was space for the switch, antenna lead etc on the other side as they all take room.

I trail fitted the key bits a number of times and re-assembled the case to make sure it would all work without interfering with the gimbals etc before I started drilling and cutting.

Step 2 – Modifying and Mounting the LED

I wanted the LED to be visible from the front of the unit. Looking at the LED, I decided that it could be bent out, and the legs cut off around half way along.

This should enable the LED to have some wire soldered onto the legs, and the legs left on the PCB should be long enough to take a standard servo plug as the wire spacing was the standard 1mm, same as a servo plug.

I marked one side of the LED with a marker so that I could remember which at round it was and make sure that I plugged it in the right way when the time came.

I found that just the remnants of the legs coming off the PCB wee not enough to hold the servo plug securely, so I found some pin connectors in the parts bin. The servo plug is now a firm reliable connection.

To mount the LED, I drilled a 3mm hole in the Tx case, then hot glued the LED in place.

Step 3 – Making the switch

As mentioned above I wanted to be able to switch between 36 MHz and 2.4 GHz. I also wanted the switch to be low profile to prevent an accidental switching. So while I had spare toggle switches which just need a hole to be drilled to install, I decided to use a double circuit slider switch.

First thing to decide was switch location – and a convenient spot on the back half of the case was chosen.

To install the switch, I drilled two holes in the case right next to each other where the switch arm would come through, then used a small triangular file to make the rectangular opening. I then drilled the two holes for the retaining screws.

I then soldered all of the wires onto the switch. The switch will switch two wires/circuits at once, so I chose the ground and power circuits. This would leave the signal wire to be direct wire (ie no switching) to both RF units. The logic for this is that the signal is most critical, so not having a switch on this should mean less exposure to signal problems.

EDIT - It has been noted later by others that you should leave the ground connected. The ground should not be left floating. I am not an EE, but word is BAAAD things can happen if you just happen to make the switch between 2.4 and FM AFTER you have turned you tx on, if you leave the ground floating. END EDIT

The slider switch is set up so that its position is the same as the system to be used relative to the antenna – ie the 2.4 GHz antenna is to the right of the 36 MHz antenna, so the right hand switch position is the 2.4 GHz position. Makes it easy to remember!

Step 4 – Antenna placement

As the RF module was going to take up one side under the top of the case, the antenna and switch would both have to go on the other side.

When looking at the case, I noticed the reinforcing plastic webs in the case, and realised the antenna hole would have to be carefully places to account for the webs. Photos below probably show this better.

It is noted that the antenna cable passes straight by the 36 MHz antenna. I have read in other posts that putting anything electro-magnetic near an antenna will affect its performance.

I have no way or competence to test this, but what I am relying on is:

• The 2.4 GHz module will be powered down when using the 36 MHz unit
• The antenna connection lead is shielded
• The contact is short compared to the length of the antenna when extended
• I am already getting 36 MHz glitching, so getting the 2.4 MHz working is the main goal.

Step 5 – Put it all back together
So once all the bits were made, drilled, soldered and assembled it was then a case of putting it all back together.

As the switch and 2.4 GHz antenna are on the back part of the case, opening (and closing) the unit is not as simple as previously, but it all works OK. So the tip here is don’t make the wiring on the switch loom too short!

Also I put additional heat shrink on the antenna connection to the 2.4 GHz RF unit, just to make sure no metal contacts could result (blue heat shrink in attached photo)


Step 6 – Bind and check
Once it was all together, the moment of truth arrived – power on stage. I turned the Tx on (this was more nervous than most maidens) and no smoke started to escape and everything seemed to be working normally, so that was good.

First was a 36 MHz range check on an existing plane – all good, no change in functionality, no glitching at 10m with the antenna down.

Next the 2.4 GHz system – all my new Rx’s binded (bound?) no problem, and seemed to work fine.

That’s as far as I have gotten so far. When I am back in the shed I intend measuring the power consumption in both modes – from what I have read power consumption in 2.4 GHz mode should be less, which means more battery time.

Next will be when I get a chance to go flying (and the wing isn’t 30 knots like it always seems to be in summer) – then the true range and performance tests will start.

Great Idea Lead. Did mine prior to the hack module coming out. My Radio is a 36 meg JR Max66. All good good with the 2.4gig Assan
https://www.rcgroups.com/forums/show...23343&page=105
Post 1562

B x

This is how my friend attached X8D to FF10. Wired 3 pin to trainer port. Place X8D in plastic box and attach it with large paper clip. This locates antenna in proper location, and Tx weight balance is good.

What's the required voltage for the RF module?

Hi,

Found nice pics of the hack of this module on the Futaba 7C-FF7 :
http://www.eppshop.nl/phpBB3/viewtopic.php?f=24&t=74

Be sure to use a safety switch instead of a non-proteced switch like shown on the pics.

my movies : http://nl.youtube.com/results?search...rch_type=&aq=f
my website : http://users.belgacom.net/TX2TX : buddy box compatibility problems between different brands of transmitters

Originally Posted by madmike8

What's the required voltage for the RF module?

I'm in no way an expert in this stuff, but from what I can tell the voltage in is based on the Tx's batteries - and most use 8 x AA's (or equivalent NiCd etc) - so around 9.6 - 12 V. I'm pretty sure that is what the Assan is made to have as it's + supply.

As for the PPM voltage, I'm not so sure if there is a standard on that - you would need one of the more electrickery minded folks to answer that.

However, I do know that lots of people have hacked lots of different brands with the Assan and other modules - so my guess is they are all conforming to some kind of standard.

One exceptioon is the negative vs positive shift between JR and Futaba - but again that is a bit out of my expertise.

Hi everybody!

Great idea Lead! I just want to share with you and the others my sucessfull mod with my MC24 and the ASSAN module.

Hi everybody,

I hacked my MX12 with the Assan X8D module.
You can download the technical PDF file here:

http://www.archive-host.com/compteur...anX8D24GHz.pdf

This file is currently only in french because I didn't have time to translate it in English, but there is a lot of pictures and it's easy to understand it.
I chose to conserve the possibility to switch between 41Mhz and 2.4GHz.
I use a bipolar switch to commute between 2.4GHZ and 41MHz (Only the VCC and GND are switched).
Don't hesitate to email me your questions.

Not really the "D" , but the Futaba "F" module without clothes...:

inside:

and out...:

Schematic:

http://www.drivecalc.de/circuits/Assan_picsd.html

I added an internal switch so I could eventually use 35hz again

Ok, here is my Robbe Futaba FX-18 V2 hack:
- plus and ground are taken out from the pins near the RF section
- signal is taken out behind the trainer plug in the other side of the PCB
- crystal is removed from the RF section
- the tx is going to be 2.4GHz only, no leds nor switches etc.
- this is a FX-18 V2, the V1 might be different
- same mods worked for the FX-14

Couple pictures attached, there are probably many other ways to do this (one being presented in the Jeti Duplex instructions for the FX-18). There is one report on the original Assan X8 thread where the third pin of the same pins (from where I took the power) is reported to give the signal. However, this did not work for me, voltage level appeared to be far too low.

Finally got around to measuring current draw for the Tx now - in 36 MHz mode it's 200 mA, 36 MHz with the crystal out 45 mA and in 2.4 GHz it's 65 mA.

So the battery time for the stock 600 mAhr battery has gone up from around 3 hours to nearly 9 - great stuff!!

Still waiting for wind to die down/not at work/time to fly/enough light/planets to align before I can do some flying/range testing

Finally got a chance to go flying after work last night. Last hour of light, and light-medium gusting winds but hey at least I got out. Flew down at Swanbourne near the SAS barracks to the nice background staccato of someone having fun with an automatic weapon of some kind at the rifle range.

Flew 3 planes in total one with 7 channel Assan 2.4 GHz Rx, and two with 4 channel chewing gum sized Assan 2.4 GHz Rx's.

Didn’t get a chance to fly any of my 36 MHz planes as only one I had with me I was not confident in putting up in that wind.

Summary – flawless performance (from the Tx/Rx anyway – the nut holding the sticks gave trouble as usual). Flew the biplane probably 300-400 m away, and was all good. Was really limited by light/wind/fear of loosing plane to SAS barracks than the radio system.

Next test will be a 36 MHz plane and a larger plane as far away as I dare