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Lightbridge Dbus
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Hello, my system is equiped with Lightbridge - A2, working fine all together.
I have the 32 bit board with 2 IMU to control the gimbal.
I use FC input for Roll & Pitch from the A2. Then I use a Sbus hub on the Lightbridge output to split Sbus connection to the A2 and the Alexmos board. The A2 receives correctly the signal and works just fine.
On the Alexmos 32bits board, I connect to the RC Roll pin, then in the GUI choose Futaba S-bus in the RC Roll in function. Then I tried many virt channels on Pitch and Yaw function but nothing works. In my RC (TG8S ) my Yaw and Pitch cahnnels are 11 & 10. Channels from 1 to 9 are busy.
So my question is, Is lightbridge Dbus signal (normally simillar to Sbus) is really operating with the Alexmos 32 board? Only 2 wires is a problem?
Is the connection with the Sbus hub correct?
Is there special things to do to assign virtual channels?
Thank you for help.
PS: Also, in case of 2 IMU, is there a real need of the FC roll & pitch connection? Does it helps more for stabilization or it is just uncompatible? -
I use futaba SBUS (12Z) with Naza (DBUS) and it works fine when split also to Basecam board. I use channels above 10.
It could be that Lightbridge DBUS is too much differ from SBUS, but I hope not. Just make syre that signal goes to signal pin on Basecam and ground goes to ground. After they are configured on GUI as you mention go to real time tab, what does the RC channels show?
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Hello Garug, thanks for your help
I checked in real time tab, I have nothing on the RC channels while signal is good on FC inputs (PWM from A2 with gimbal switch on).
Then, I check my wires and if I have the +5 (Because Dbus wire from Lightbridge is only 2 wire - and signal) +5 is ok, coming from A2 and splitted by Sbus hub
Then I connected back to PWM mode from A2, I mean D2 & D3 connected to RC-Pitch input and to RC-Yaw Input, with gimbal switch off in A2. It works fine and in real time time I get signal on realives RC imputs.
Leaving these 2 inputs connected like this, I plugged back the Sbus to RC Roll input, choosed Sbus Futaba in command line, virt channels, and I still have my PWM RC signals in real time tab like it doesn't record Sbus in RC roll in mode. Normally Dbus lightbridge could be replaced by Sbus futaba receiver to control A2, so normally the Lightbridge should work on the basecam board.
By the way, for example, in the A2 the channel for D2 (RC pitch) is 11 and the channel for D3 (RC Yaw) is 12, do I have to choose virt channels 11 and 12?
I am a bit lost by now :)
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You got me a bit lost too ;-)
I do not get what you say about +5V. You should not connect +5V. only connect ground ands signal.
The SBUS needs to be connected to the dedicated pins (RC_ROLL pins, make absolutely sure that signal goes to signal and ground goes to ground) on BaseCam board and RC_ROLL pin mode needs to be set to futaba s-bus on GUI and the correct virtual channels need to be assigned to what you want to control. -
Ok, sorry I try to make simple :-)
Dbus from lightbridge is only 2 wire (signal and ground)
Sbus is 3 wires, I tought it was Ground, +5v, signal. Am i wrong? Anyway ground and signal are ok.
- It is connected Dbus is connected to RC_Roll pins and Sbus Futaba made pin is selected.
- From my RC, for pitch i use channel 11, for Yaw channel 12, so in RC tab I choosed Pitch=virt_Ch11 and Yaw=virt_ch12.
Is this correct setting?
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Got some imrpovements,
1 - I connected directly the lightbridge via Dbus to the Alexmos board with Flight controler and it works fine through the Sbus control.
2 - Then I place the Sbus Hub between Lightbridge and Alexmos board, still works fine.
3 - Finally I plugged A2 flight controller to Sbus Hub -> No more signal in the GUI real time TAB on RC inputs.
4 - Unplug the A2 Fc, signal is back on the board.
So it looks the input of the A2 Fc disturb or even block the signal to go to the board. -
Adding more,
thinking the midle wire of servo wires would disturb signal with a +5v, I connected all A2, lightbridge, hub and Alexmos with only 2 wires cables ( Ground & signal)
But stille same, when i plug A2 on the Hub (X2 input) Sbus signal disappear on Alexmos board
:( -
Sounds like the Lightbridge DBUS output is compatible with BaseCam, but not strong enough to provide the signal for several devises. That is a bit strange as SBUS can be splitter for several servos etc. and Futaba SBUS works good when splitter for BaseCam and Naza.
Are you using same battery for Lightbridge and BaseCam, is so the ground is already connected and You could try connecting just signal to BaseCam.
And make absolutely sure signal goes to signal and if ground is connected; ground to ground. Your problem sounds like they might be reversed. (check that the connector is connected right way on BaseCam)
It should be acknowledged that this kind of connection, though it should not, could cause problems also during flight and in worst case lost of control.
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Lost of control!!! Hope not
Basecam has its own 3S Lipo, Lightbridge Air system is connected on main 6S battery
I checked connection, all is right way connected.
May be DJI (let's say for consumption reason) output a weak Dbus signal because tey assume the lightbridge will feed only 1 other DJI system. But if I remember well I read another post saying that he connected naza to lightbridge and an Sbus decoder to control a gimbal. So if it can feed a dji device and a decoder, it would be ok for me.
I will investigate in the ground story you mentioned, it sounds a good way to look at.
Keep you informed, thank you for your help -
I worked on it a bit
I have a phantom with NAZA V1
- I connected the naza and my gimbal behind sbus hub and feed them by lightbridge, all of them powered by same 3S lipo, => IT WORKS FINE
- 2 Then I replaced lightbridge by a FrSky Sbus receiver and NAZA by A2 => IT WORKS FINE
Only when I want my A2 and gimbal working on Sbus lightbridge, I have nos Sbis signal on the gimbal.
:-\ -
To finish Garug, I tried everything you told me. Even I tried to power A2, LB and board with same battery. Still it does not work.
I really don't understand why it is the only case that fails compare to all sonfigurations I tried
:(( -
an oscilloscope would be useful for troubleshooting and seeing what is going on, otherwise it is difficult to say. Oscilloscope I would have, but unfortunately not A2 or LB.
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And what do you think about this to boost Sbus signal (On another forum I got confirmation Dbus signal is low)
http://www.intermodel.fr/accessoires-recepteurs/332-signal-booster-servo.html
Might be cheaper than buying an oscillo. Just wonder if it would fit Sbus specs or PWM specs
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There is no need for oscilloscope, if the signal is already tested low. A signal amplifier/divider/booster is a good solution.
It would however be good that someone would have tested this, possibly measured with oscilloscope, to see that the levels are ok and signals clear. If something goes wrong with SBUS, the connection to flightcontrollerg will also probably suffer. A small risk, but something to acknowledge. -
Hi Garug, just received the servo booster today (link in prev post). Just plugged it and it works fine. :)
The issue was the weak signal.
Thanks for your help
BR -
Hi Gwen, what kind of sbus hub you use? could you show me where to buy?
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Hello I use this cable, then I didn't need any HUB because it is already a Y cable
https://www.servocity.com/html/boosted_servo_extensions.html#.VN_XsPmG-Sp -
THANKS
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no need for servo booster?
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HI Gwen, I just try a boosted Y cable from servocity. A2 assistant software said lost RC connect and GUI no response at all. what do I miss?
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