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May 25, 2007, 04:54 PM
cp1
cp1
Registered User
Discussion

Royal Evo going FASST


I have managed to attach the Futaba T6EXP 2.4 GHz transmitter to the buddy connector of my Multiplex Royal Evo 12. It transmits seven channels.

I am not recommending this modification to anybody. I am only reporting what I did and how. I will not write a detailed how-to, because I think that only people with sufficient skills in electronics should try the experiment at this time. If you wish to do so you do it at your own risk.

What I did is fully based on Rudy's findings, published here and in the German RCLine forum. He has reported how he connected the FASST transmitter to his Graupner MC22 radio (https://www.rcgroups.com/forums/show....php?t=676607). Meanwhile he has also pointed to the fact that Futaba's R606FS actually is a 7-channel-receiver - with only one connection missing (see http://www.rclineforum.de/forum/thre...tuser=&page=4).

First, the receiver: I have added the small 220R resistor, which is missing at the 7th channel's signal lead. By looking at the pic the above link points to you will easily find out where the resistor is missing. After that, my scope displayed a servo signal in neutral position (1.5 ms) at the lead.

Second, the transmitter: It sits piggy-packed on a somewhat larger board, which carries the LEDs, the buddy connector, and the 5V voltage regulator. If you open the case and look at this board, you will see four leads connected on the left and three leads on the right side of the board. The four leads on the left are for the buddy connector only, so I removed them. The three leads on the right carry ground, battery plus, and the signal. The signal package is a usual 22 ms frame with the servo pulses active low and 3.3V peak voltage.

Third, adapting the Evo's buddy connector: Pin 4 carries the servo signal package, active high, the peak voltage is the same as the battery voltage. I made a small inverter circuit, using a BC547, a 4k7 resistor at the collector lead, a 3V3 Zener diode between collector and ground, and a 10k resistor at the base lead. I connected the inverter to the regulated 5V on the larger board.

The supply voltage comes from pin 2 of the buddy connector. Pin 3 is connected to battery minus or ground. You have to bridge pins 5 and 3 in order to switch the Evo's Hf transmitter off and have the signal routed to pin 4.

That's all. The 2.4 GHz box is working flawlessly and fully transparent as the Evo's transmitter modul.

I am also reporting my experience as a criticism to Futaba:

Why was the R606FS artificially limited to six channels?
Why do you let us wait for a 7-channel 2.4 GHz solution which fits the needs of advanced model pilots?
Why couldn't you do what I did as a product? A 2.4 GHz 7-channel modul that can be attached to the buddy connector of almost any radio would be welcomed by many model pilots.

Regards
Christian
Last edited by cp1; May 26, 2007 at 03:59 AM.
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May 25, 2007, 05:59 PM
Registered User
Good Work!! If you have the English language software V1.40 installed (with the shift select option) can your pulse inverter circuit be eliminated?

How do you perform the range check function?

EDIT: I see you have to drop the EVO logic voltage from B+ to 3.3V so at least that part of the inverter circuit is needed I believe.

Buzz
Last edited by Tfour2; May 25, 2007 at 07:56 PM.
May 25, 2007, 10:08 PM
FHSS won Europe hitherto
Hi Christian,

Check your link if pg.4 ist really that very page you want to link

Pls do not forget to report about loss of channel 3 failsafe and the 'Power Down'-feature.

Rudy
May 25, 2007, 10:11 PM
FHSS won Europe hitherto
Hi Buzz,

that sort of inverters are very simple things...

The visible big diodes reduce the voltage arriving at the DX6 (T6EXP) stabilizer.

Rudy
Last edited by Rudy Vienna; May 25, 2007 at 10:18 PM.
May 26, 2007, 04:10 AM
cp1
cp1
Registered User
Hi Buzz,

I did not know about the shift option. Anyway you need to do something for limiting the signal voltage.

For range checking I have to put the transmitter back into its original environment. I am using a servo connector for the three leads that are necessary, so I can easily put it back into the T6 case.

Christian
May 27, 2007, 11:33 AM
FHSS won Europe hitherto
The correct german link is http://www.rclineforum.de/forum/thre...htuser=&page=3

Page 3!

I do not know, if it will work correctly together with a new Futaba 7-channel Tx!!, due to possible software alternations.

The selfexplaining pics about R606 containing a 7th output, only a R220 is necessary:
May 28, 2007, 06:35 PM
Proud to eat Kraut ;-)
Julez's Avatar
Hi!

Why don`t you guys just link directly to the specific posting?

http://www.rclineforum.de/forum/thre...16#post1678416

Christian, does your setup transmit the 7th channel?

Cheers,

Julez
May 29, 2007, 02:38 AM
cp1
cp1
Registered User
I was not aware of how to address a specific posting on RCLine. Thanks.

Julez, why don't you just read? ;-)

Christian
May 29, 2007, 03:05 AM
cp1
cp1
Registered User
A picture of the 2.4 ghz Evo:
May 29, 2007, 06:56 AM
Proud to eat Kraut ;-)
Julez's Avatar
Hi Christian!

Your setup looks great!
Now that I`ve read at RCL that the 7th channel is transmitted, I will look into transplanting the board into my FC18 once again.

One can link to posts on RCL directly by clicking on the symbol next to the posting date.

Cheers,

Julez
Jun 27, 2007, 06:00 AM
cp1
cp1
Registered User
Here is the adapter circuit that has been checked against a number of Transmitters (i.e. Multiplex Royal Evo, 3030, 4000, Graupner MC-22). Input is the PPM data stream that is available at the buddy connector. Polarity does not matter. Supply voltage (7 ... 25V) can as well be drawn from the buddy connector and is passed through to the T6 Tx module, which has its own 5V-regulator.

The adapter forms a PPM data stream with positive pulse widths the Tx module can interpret. Different pulse widths switch the Tx module to different modes. These are the pulse widths and the respective modes as published by Rudy on the German RCLine board:

less than 400 Ás: not usable
400 ... 420: regular transmission without failsafe
425 ... 440: regular transmission with channel 3 failsafe position transmitted as the channel 8 signal.
445 ... 500: power down mode for range check.

Since capacitor specs are usually not precise, you cannot rely on achieving the desired pulse widths with the computed R/C-values (12k, 1k2, 33n). So, instead of the 12k resistor I am using a 5k trimmer in line with a 10k resistor. With the switch open I adjust the trimmer so that the module switches to power down mode (green LED on, red LED blinking). Then, by closing the switch, it safely goes to regular transmission including failsafe.

Again, I am only reporting what I did. I am not recommending this mod to anybody. Because of the high risk a transmitter shut down could cause, the adapter circuit should be built and used only by people who have sufficient skills in building electronic devices.

Regards
Christian
Jun 27, 2007, 11:29 PM
FHSS won Europe hitherto
1) Christian told me, that his channel 8 transmits 1ms.

Consequently failsafe will function well.

If a Tx sends 1.5msec as basic value (center) on channel 8, the failsafe will be servo-center !!
And FULL-speed with Graupner/JR at plus 76% Servoposition.

Graupner/JR needs minus 76% or lower for 'Engine OFF'

Please make all tests without prop if feasable or fixed model.

2) I use Cristians device now with my mc22-T6 combo instead of the shown former inverter. Therefore I can now use engine-failsafe on channel 3 - after a lot of Tx-programming and plug changes too.

Rudy
Last edited by Rudy Vienna; Jun 27, 2007 at 11:37 PM.
Jun 28, 2007, 06:32 AM
slow but inefficient
Ron Williams's Avatar
Could this transmitter now be said to be, "Half fasst"?
Jun 28, 2007, 07:15 AM
Turbines suck ;-)
Quote:
Originally Posted by Ron Williams
Could this transmitter now be said to be, "Half fasst"?
LOL

You could be mistaken for a Englishman with such subtle humour
Jun 28, 2007, 10:11 AM
cp1
cp1
Registered User
Possibly half an Englishman ;-)

Name it whatever you like, Ron. Fact is that it combines Futaba's 2.4ghz technology with all the comfort the Evo has to offer, apart from the 7 channels limitation. I have no need for more channels at this time. So I am quite satisfied.
Last edited by cp1; Jun 28, 2007 at 11:12 AM. Reason: typo


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