2-Axis to 3-Axis Conversion....simple, light weight, and cheap!

[Bartman]

Hi folks,

Below you will find info I've put together to convert a single-operator heli with a 2-axis mount to a heli that can be used with dual operators and have very similar performance to one equipped with a 3-axis mount.

About two and a half years ago I wanted to add 3-axis performance to my main photography heli but didn't want to add the weight of a third drive motor or retracts. After all, panning a camera is identical in motion to Yaw of the helicopter so I came up with a way to transfer camera Tilt and helicopter Yaw to a second operator so my 2-axis camera mount could be used similar to how dual-operator 3-axis equipped helicopters perform.

Before I get my arse flamed for suggesting that the performance is identical, it isn't. The more expensive, heavier, and complicated dual operator rig with the high end 3-axis mount will offer more performance across a wider range of operating environments.....

.......BUT.......

.....if you give this a try I guarantee you will be amazed at how well it works and how much you can actually do with it.

The video ought to be enough to help you decide if you want to give it a try so feel free to use the thread to ask whatever questions haven't been answered in the video and to post samples of the video you shot with your completed conversions!

The module used is from Pololu.com, it's a 4 Channel RC Servo Multiplexer
http://www.pololu.com/product/2806

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[apsussex]

Bart this is fantastic, absolutely perfect for my needs, have managed to find a UK website that stocks this switch and just made the order. Very excited to receive this now .

 

[Bartman]

Well you've made me a happy chap.

 

[apsussex]

Hi Bart, received my multiplexer yesterday and have soldered up all the pins. Only pan and tilt are required as I want to keep the master with control of the shutter and modes.

I havent connected to the receivers yet, but will post up photos once its done. Your video was very helpful and I did notice you need to use the training mode for switching between outputs. Is this a fairly simple operation once everything is connected?

Thank you
Sam

 

[ChrisErl]

Bart I love it, I was trying to figure out how to set this up on my Phantom2 about a month ago but with it using sbus it was giving me fits. I'm also building a trifecta for holidays which I'd like to add a 2axis möbius gimbal. Having this kinda control is well Wow.

I'm going to order a pair and give it a try. I'm sure I'll be back with questions.

Chris

 

[apsussex]

OK this is all good, as it turns out I didnt need to use the learn function, it just seemed to work. I had the Futaba 14SG setup using switch SD (channel 8 on my setup) which is to switch between output channels..

I may update the controller at a later date, but for now coming in at about £65 delivered for a second controller/receiver/switch and a bit of spare time, I have the option to use a second controller for the gimbal at just the flick of a switch.

brief video of it working here... very happy!!

 

[Bartman]

Bart I love it, I was trying to figure out how to set this up on my Phantom2 about a month ago but with it using sbus it was giving me fits. I'm also building a trifecta for holidays which I'd like to add a 2axis möbius gimbal. Having this kinda control is well Wow.

I'm going to order a pair and give it a try. I'm sure I'll be back with questions.

Chris

Chris, does the Phantom have the standard NAZA module inside the plastic body pieces? Are you using the DJI white radio or a regular RC radio?

 

[Bartman]

OK this is all good, as it turns out I didnt need to use the learn function, it just seemed to work. I had the Futaba 14SG setup using switch SD (channel 8 on my setup) which is to switch between output channels..

I may update the controller at a later date, but for now coming in at about £65 delivered for a second controller/receiver/switch and a bit of spare time, I have the option to use a second controller for the gimbal at just the flick of a switch.

brief video of it working here... very happy!!

that's it! i never really planned to make a 2 man rig act like a one man rig, it was the otehr way around for me but i guess it converts a 2 to 1 just fine!

 

[ChrisErl]

Chris, does the Phantom have the standard NAZA module inside the plastic body pieces? Are you using the DJI white radio or a regular RC radio?

The phantom2 runs a naza v2 but it firmware is unique because of the smart battery system. I've also got a phantom v1.2.1 that runs a naza v2. I have the stock radio on a shelf and use a Futaba 8fg
Because Both are sbus single lead out put, I wonder if I need to go with non sbus rx's to make this work? I do have a Futaba sbe-1 converter as well.

 

[Bartman]

can't you put a futaba receiver in there and just run discreet channels instead of sbus?

fwiw, futaba has a 10 channel sbus encoder that should become available in late february. i've had to abandon using an A2 for a new quad until that sbus encoder is released.

 

[henrysj]

just ordered a couple of units - can't wait to give this a shot. Cheers for all the info Bart

 

[Bartman]

no problem, please report back with your results. are you doing the one to two man conversion or what apsussex did with the two to one?

 

[henrysj]

Hey Bart,
Got this fitted and test flown today. Your tutorial was spot on - only took me about an hour to fit including making the servo cables.
Did have to enable the inversion but easy enough done following section 9.3 of this doc:
https://www.pololu.com/docs/pdf/0J60/pololu_rc_switch.pdf
Did a few test flights this afternoon with brilliant results. Put a load of expo and dual rates into the second tx to get nice smooth yaw/pan movements.
Only thing I haven't sussed out, and I'm hoping its due to lack of time playing with it, is the failsafe. Was hoping that if I didn't use a 2nd tx then the failsafe on the pololu board would automatically give me control of yaw and camera tilt to the master tx no matter what position the IOC switch was in. I'm thinking this could be due to the 2nd rx giving it a failsafe command. Have you had any luck with this?

 

[Bartman]

Henry,

We designed that into the system that we were developing (the red board in the video) where the absence of a second signal would keep it tuned into the first but the Pololu doesn't have that. The red board also had a signal test where it wouldn't switch if the signal was there but unusable.

To disable the Pololu system just unplug the servo connector for the switching channel and it will only use the master outputs (single operator mode)

Are you using the set up as it was explained in the video to get two-operator functions out a two axis camera mount and carefree mode?

 

[henrysj]

Yeah - exactly the same, giving yaw and camera tilt control to 2nd operator when switched to carefree mode. Never really used carefree mode before so took a little getting used to trying to disable that part of my brain but after a couple of fights and tweaking the rates we were getting some good results. I do have camera tilt on the throttle channel at the moment that we were finding doesn't give the smoothest action compared to the pan so need to have a play with the H3-3D to see if I can slow the tilt speed to be more like the h3-2d

 

[Bartman]

Yeah - exactly the same, giving yaw and camera tilt control to 2nd operator when switched to carefree mode. Never really used carefree mode before so took a little getting used to trying to disable that part of my brain but after a couple of fights and tweaking the rates we were getting some good results. I do have camera tilt on the throttle channel at the moment that we were finding doesn't give the smoothest action compared to the pan so need to have a play with the H3-3D to see if I can slow the tilt speed to be more like the h3-2d

that's awesome, so glad to hear someone has tried it. i think it works great and brings a lot of new utility to an old heli or one built with simplicity as a high priority.

i've got to finish the new one i started a month or two ago. it'll do exactly what i outlined in the video so i'm a believer in the trick!