Controlling two models

[Philip MitchellParticipant @philipmitchell70963]

looking for some advice, I intend to use a Futaba 6 channel transmitter (2.4Gh) and would like to control two models from it. The Mother boat would have 4 channels and the Daughter boat would use two. Is it possible for one transmitter to control two receivers OR do I have too use two transmitters to operate the two models.

[Philip MitchellParticipant @philipmitchell70963]

Control two receivers from one transmitter

[BanjomanParticipant @banjoman]

Philip,

Unless I'm much mistaken, it will be impossible to do what you have in mind, as a 2.4 GHz t/x locks onto one and only one specific r/x at a time. You can ususally set up a quality t/x like a Futaba to remember a number of t/x–r/x combinations (usually called model memory or something similar), but only one of those can be active at a time.

If you think about it, it is actually quite logical: one of the great advantages of 2.4 GHz technology is that your t/x will only ever talk to one specific r/x at a time, which is why it will never interfere with your neighbour's model.

I suppose it might in theory be possible to run two r/x off a single t/x on one of the traditional frequencies, e.g. 40 MHz, as there you will get interference between models if two users are running the exact same frequency simultaneosly … but on 2.4 GHz, as far as I understand these matters, it won't work.

/Mattias

Edited By Banjoman on 12/09/2015 22:29:15

Edited By Banjoman on 12/09/2015 22:29:28

[Dave MilbournParticipant @davemilbourn48782]

This is not my experience i.e. that binding a receiver to a transmitter actually prevents that transmitter from operating any other receiver which is also bound to it. I've not tried switching on two models at the same time but I do have several Hitec 2G4 receivers which are all bound to the same transmitter. That's why my Hitec set provides me with different model memories, whereby I can switch on the transmitter and then select which model I want to operate. After all, the receivers have no way of "knowing" that there are other receivers also hearing the same signal. At present I have four models, all with Hitec receivers operating happily from the one transmitter. The model memory retains the settings for servo reverse, exponential movement etc, so those would all have to be common to both models.

With that proviso I can't see why what you propose isn't theoretically possible as long as you are also careful not to allocate the throttle of both models to the same transmitter stick. Work it out……………

Frankly I'd buy a second radio for the daughter boat, especially if it's only 2 channels. Short cuts like this usually end up in you going the long way round to doing what you were trying to avoid in the first place.

DM

[Malcolm FraryParticipant @malcolmfrary95515]

Quite easily settled by anybody who has one transmitter and more than one boat with receivers bound to it. Switch them all on and see what happens.

The memory refers to the stick response settings programmed into the transmitter for specific models. The "wrong" model will respond to the commands it receives, just not in the way you hoped.

One person controlling two boats rarely works well, so a separate set for the daughter boat does make sense. Apart from anything else, the mother boat transmitter will probably be using more than just the normal two channels, so there is a good chance that you would run out of usable sticks for analogue channels.

[BanjomanParticipant @banjoman]

Dave,

I never said that you could not bind multiple receivers to the same 2.4 GHz transmitters – of course you can, and that's what I meant by "remember a number of t/x–r/x combinations (usually called model memory or something similar)".

However, in my experience you then have to select one of those memorised models, which to me seems to indicate that only one t/x–r/x binding would be active at any given moment. As you say: "different model memories, whereby I can switch on the transmitter and then select which model I want to operate". But this is indeed only my interpretation, and it may well be that I am wrong.

The whole thing is easilly tested, though, as Malcolm suggests, if someone (Dave?) who has a transmitter bound to several receivers turns on both that transmitter and two of the receivers simultaneously to see what happens. I cannot try it myself just yet, as for the moment I only have a single receiver.

/Mattias

[ashley needhamParticipant @ashleyneedham69188]

Or you can cheat (acrylic rod)

Ashley

[Colin BishopModerator @colinbishop34627]

Logically, as already mentioned, you would have to allocate the transmitter channels between the receivers so that the left stick would control one boat and the right stick the other. This would give steering and throttle for both models and any remaining channels can be activated on whichever boat you like. However trying to steer two boats simultaneously sound like a nightmare. Unless you are really adept at doing two things at once one model would need to be stationery or on a straight course while you are operating the other and this then of course raises issues as to whether the throttle sticks should be ratchet or spring return. I think they would both have to be ratchet but you would need to be very certain where the motor off position is.

The idea sound feasible if you have enough total transmitter channels to play with and tend to concentrate on driving just one boat at a time.

Colin

[fredParticipant @fred20856]

I have two receivers (2.4gz) bound to the same transmitter in two boats.
Just switched everything on and the controls in both boats respond the same
Which I believe answers the original question?

Fred

Edited By fred on 13/09/2015 12:59:34

[Dave MilbournParticipant @davemilbourn48782]

There's no fundamental disagreement here, Mattias; just my clumsy way of explaining things, maybe.

"Binding" fixes a receiver to the signal from the transmitter to which it's bound. You can bind as many receivers to one Tx as you like (or need); they will not respond to any other Tx on 2G4.

The computerised model memory, as Malcolm says, involves programming the Tx to move specific servos in specific directions and by specific amounts e.g. left rudder command rotates the rudder servo clockwise; full rudder stick movement = 80% movement of the servo. You can program several different models (i.e. sets of settings) into the Tx but you can only run one set at once. That means that if – for whatever reason – you want to operate two models simultaneously from the same Tx then all of the settings for the models must be identical. Either that or you have to allocate one stick for one model and the other stick to the second one. As Colin suggests, that is the stuff of nightmares.

Incidentally I've just had both of my Huntsmen switched on at the same time and I can confirm that both boats respond to the Tx – although the rudder commands are opposites (i.e. Left stick gives left rudder in one and right rudder in the other) because of the way I have the servos fitted in each boat. I never doubted it but it's comforting to have it confirmed!

Philip – that's at least two votes for a separate radio for each boat. Colin is hedging his bet!

DM

[Philip MitchellParticipant @philipmitchell70963]

Thanks to everybody who has read and replied to my post, certainly given me plenty to think about ! 😆

I will set up, on my work bench, two receiver's and a few servo's and see how I get on before I fit the gear into the models. I will report back my success or perhaps failure in due course. 😃

Phil

[Colin BishopModerator @colinbishop34627]

If you want full control of both boats plus ancilliary functions then I think you would run out of suitable channels on a single TX as many auxiliary channels are simple switches. (Is this the Theodor Heuss lifeboat by any chance?).

For full flexibility at a moderate cost I reckon you best bet would be to have two separate radio combos and mount the two TXs in a tray with a neckstrap so you can use either as required. A couple of extra arms would come in handy too (sic).

Colin

[Dave MilbournParticipant @davemilbourn48782]

Blimey! The Admiral has climbed off the fence – but two trannies in one tray? Two extra arms?? You've been watching those Rick Wakeman videos again, haven't you, Colin?*

That's three votes now, Philip. Ashley doesn't count 'cos he cheats!

DM

*(Only really sad old Prog Rockers from the 70's will understand that reference).

[Colin BishopModerator @colinbishop34627]

Yes, I do realise you might look like an ice cream seller in a cinema…

Not a particular fan of Rick Wakeman but we did enjoy a Justin Hayward concert the other day.

Colin

[Dave MilbournParticipant @davemilbourn48782]

"And now for something completely off-topic…." **LINK**

DM

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