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Futaba SBus to PPM converter


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#1 garris2

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Posted 09 March 2012 - 05:39 AM

Hi all, I'm looking for a Futaba SBus to PPM converter.

Does anybody know of such a thing with a proven working track record or would anybody be interested in building such a thing? (Hint to Thomas)

I'm sure it would be a great seller.

SBus protocol
I can't vouch for the accuracy or completeness.
http://www.flightron...s-bus-protokoll

There is also this but it is sold as a pcb only and I dont have the knowledge to program it, ( I could build it), I could not find any reports attesting to reliability, some negative actually.
http://ddfpv.de/projects/s-bus-to-ppm/

I would like to feed PPM into an OSD that has newly developed firmware to support PPM in while still having ordinary servo connectivity to the receiver for things such as Head Tracking, flaps etc

I've considered a PWM to PPM encoder but it would add wiring complexity as I still want access to the receiver outputs for the above mentioned things such as Head Tracking and Flaps etc.

If eventually I need to use a PWM to PPM encoder I will stick with my Futaba R6014HS, If I find a proven (or one is built) SBus to PPM converter, I will be using a R6108SB receiver

Geoff

#2 Kilrah

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Posted 09 March 2012 - 10:12 AM

There is also this but it is sold as a pcb only and I dont have the knowledge to program it, ( I could build it), I could not find any reports attesting to reliability, some negative actually. http://ddfpv.de/projects/s-bus-to-ppm/


That's the only one I've seen around.

#3 Mr.RC-Cam

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Posted 09 March 2012 - 12:15 PM

I've never even touched a Futaba SBus system so it is all a mystery to me. But maybe the best solution would be to add the SBus decoding into the OSD. I found a discussion where a MK user added it to his flight controller. Maybe you should sweet talk the OSD maker into adding something similar.

Here's the MK SBus code:
http://www.kri.dk/Fu...m_S-BUS-V0_01.c

Here's the discussion:
http://forum.mikroko...opic-18331.html
- Thomas

#4 Kilrah

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Posted 09 March 2012 - 02:41 PM

Another solution could be to get a FASST-compatible FrSky TFRSP: http://www.frsky-rc....ducts.asp?id=80

It has a PPM output, AND servo outputs for CH5-9.

Much cheaper than a Futaba receiver too.

#5 garris2

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Posted 10 March 2012 - 03:30 AM

Thanks for your replies guys, the OSD's makers name is Bill (no more clues will be given). I will try to sweet talk him and in the mean time I might try to build the project above.
I looked at the FrSky receivers as linked by Kilrah but they are limited to 10 channels and I would like to make full use off my 12 available channels with my existing system.

Geoff

#6 rejaorac

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Posted 01 September 2012 - 08:19 PM

hello all forum rc agradesso to be part of this forum
I use ese receptor changed in a simulated funsiona pefeito wireless so I entedir the bus fuciona s the same way and that


Step by Step Walkthrough


Please read the whole process before start! To exclude the possibity that your receiver is dead on arrival (DOA), you should first connect a regular RC servo and power supply to check that it is working correctly.
Step 1: Open the case


Posted Image
The case consists of a bottom and top part. They are connected by four notches snapping into the corresponding cutouts on the lower case. Take care of electrostatic discharge (ESD) risks by tapping a radiator or other metallic grounded object (personal computers are grounded) before opening the case. Best practice is to use an ESD arm strap, if available.

Push the notches back with a small screw driver (blade width of 2.5 mm fits perfectly) and at the same time gently apply pressure to move the two parts away from each other.

Watch out to not pull on the antenna wires, you can remove the rubber tubes holding them to the plastic case.
Step 2: Remove Resistor connecting Plug


Posted Image
Depending if all seven channels should still be usable, two options exist: You can connect the sum signal to an additional header, which you should fix tightly, e.g. by hot glue, or you disconnect the servo signal on one channel and connect the sum signal to this header.

This tutorial will proceed by disconnecting channel 7, as this channel is not usable with the six channel T6EX transmitter. Desolder now the resistor in front of the header for channel 7. In theory you can undo the modification by removing the cable (later step) and re-adding this resistor. The receiver is build in a lead-free ROHS process. The melting temperature is therefore higher than with usual solder. We had to ramp up the soldering iron to 370° C (700°F) to melt the solder. Apply heat to both sides of the resistor until you can gently slide it off its position.
Step 3: Connect PPM Sum Signal


Posted Image
This step connects the sum signal to the freed header. You need a very tiny cable. Remove the insulation by 0.5 - 0.8 mm (0.3”). Apply solder flux to both ends and cover them with plenty of solder. Place one end on one of the two marked pins (it is easier on the left IC, as you have additional space on the edge) and solder it to the pin. Make sure that is is connected right by gently pulling on the cable. Place the other end on the signal pin (see photo) on the header and solder it.
Step 4: Check


Check for remaining solder on the PCB or bridged pins. It might be a good idea to secure the sum signal cable against vibrations by hot glue or epoxy. If you have an oscilloscope at hand, you should get five signals of about 1 ms, 20 ms break and the same again. The PCB should now look like the photo.
Posted Image
Step 5: Close the case


You can easily add the case by placing the pcb inside and snapping the notches back into the bottom part. Your receiver now looks exactly the same. It might be a good idea to mark port 7 as sum-signal out.

#7 rejaorac

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Posted 02 September 2012 - 10:20 AM

sou brasileiro fanatico por heli modelismo sou navato na aria de helimodelismo tenho poco conhecimento na aria de eletronica essa ateração do receptor r 617fs acima postada por mim me gero uam duvida sera que ar posabilidade de funciona o esquema dessa alteração para o treinir sei fio se tiver auguei que possa avaliar as diferencia entre o WTR-7 FASST e essa alteração o problema e que um e in entrada ppm e o otro e out saida ppm por vafavor essa possabida de usa essi sistema comu treini sem fio tenho gande sartifação de fazer pate deste forum obrigado a todos que compatilha estas maravilha da eletronica com nosco valeu todos??????


'm Brazilian fanatico by heli modeling navato am in aria of helimodelismo poco have knowledge in this aria of electronic ateração receiver r 617fs above posted by me me gero uam doubt that air will be posabilidade works of this scheme amendment for the wire if you know treinir auguei that can evaluate the difference between the WTR-7 FASST and this change the problem and that an entry ppm and in and out of each other and the ppm output for this vafavor possabida of essi system uses wireless commu treini have gande sartifação making pate this forum thanks to everyone who compatilha these electronic marvel with Nosco earned all???

Edited by rejaorac, 02 September 2012 - 04:00 PM.


#8 garris2

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Posted 03 September 2012 - 07:19 AM

I've decided to go down the PWM to PPM converter route in the meantime as I don't think there is enough interest in the ET OSD community at the moment to warrant Bills time and effort.

Geoff