how to change controls on Spektrum DX6i?

[caterpillar]

Does someone know how to change the functions of the controls on a Spektrum DX6i in 2 different modes?
I found this picture (not sure who it is from) but it seems to be possible on a DX5e so it must be possible on the DX6i one would thinks so.



So in excavator mode the controls shall have a different function than in driving mode.

if anyone knows how to configure that, pls let me know.

[fhhhstix]

With a DX6 you can use two different receivers with different model memory and switch between them. On the DX5 he is probably using a dual relay switch to cut or supply power to 8 out puts (4 channels y'ed into two separate out puts).

Travis

[fhhhstix]

Here is a diagram of how it could work, and if you had different ESC's to run you could Y off several switches together from CH 5 to switch the signal instead of the power.



Travis

[footprint]

Originally Posted by fhhhstix

Here is a diagram of how it could work, and if you had different ESC's to run you could Y off several switches together from CH 5 to switch the signal instead of the power.

Travis

Ok, now i feel like a complete idiot for not seeing this earlier, Elegant in its Simplicity. Ive seen the German y split do-hicky but this is where its at.
Set one timing circuit to ~1ms for one transistor and the other to ~2ms connect to the "gear" switch and just switch the actives.
Having spent the last few weeks working on my 16ch microcontroller im well pissed at myself.
I'll breadboard something up in the next few days.

[caterpillar]

Many thanks Travis. You are a star! would this be the only possible way they could have done this mode switching? I'll try to track down were I found the picture and see if I can get the guy who made this work to share his secret.
rgrds
Koen

[JensR]

Why would you switch the signal?
That means your switch needs to be able to switch each signal - you'd need a 4 pole, double throw switch.
If you switch minus or plus, you only need a single pole, double throw one - easier to get, easier to wire up.
Or am I missing something?
Are you using some kind of electronic switch, like the ones from Servonaut or CTI?

You could use a servo-actuated switch, too. And then it is (IMO) better to use the SPDT switch.

One thing to consider: If you reconnect a servo or ESC, it will "jump" to the position/speed the stick demands, which might be different from its current position.

[fhhhstix]

Originally Posted by JensR

Why would you switch the signal?
That means your switch needs to be able to switch each signal - you'd need a 4 pole, double throw switch.
If you switch minus or plus, you only need a single pole, double throw one - easier to get, easier to wire up.
Or am I missing something?
Are you using some kind of electronic switch, like the ones from Servonaut or CTI?

You could use a servo-actuated switch, too. And then it is (IMO) better to use the SPDT switch.

One thing to consider: If you reconnect a servo or ESC, it will "jump" to the position/speed the stick demands, which might be different from its current position.

Go look at the diagram I do show using a SPDT switch to cut the power if using all servos.

Here is you explanation for cutting the signal the alternative for ESC's instead of servos.

Well for this to work you have to supply power to the receiver to maintain radio contact to operate the switch or a servo operated switch. So the receiver will always have the ability to send a signal. On an ESC if you don't cut the signal it will always be able to work regardless of what you do with the power or ground in the lead going to the receiver since the ESC gets it's power from the battery connected to it. Most ESC's have a BEC in them so the power and ground are only needed to power a receiver and not needed in this set up.

Most of the good ESC's (unless you use the cheapest one you can get) have a fail safe built in if it looses signal. Even the cheap ESC's that come in the Tamiya kits have a fail safe in them. You should have know problem cutting the signal. Digital servos can have fail safes programed in as well.

Dimension Engineering offers a nice DPDT electronic switch Link that you can Y harness together to control 4 separate inputs at once. so for about $80 you can make a 5 ch radio into a 8 ch radio with all 8 Ch's being proportional. $30 a piece for the switches and $20 for a Y harness and extensions.

Travis

[JensR]

Hi Travis!

> On an ESC if you don't cut the signal it will always be able to work regardless of what you do with the power or ground in the lead going to the receiver since the ESC gets it's power from the battery connected to it.

For an ESC, cutting the ground has the same effect as cutting the signal, as the signal uses the same ground.
So, because ground is common, you only need one cheap switch instead of multiple expensive ones, plus you can combine servos and ESCs:

Most digital servos have some kind of fail safe - the cheap ones "just" actively stay where they are, the better ones can be programmed. Analogue servos will have no holding force if you cut signal.
Neither type of servo will have holding power if you cut plus or ground.
So, if you _do_ need holding force with your servo, you must use a digital one and you must cut the signal and only the signal.
But if you do _not_ need holding force, you can use any kind of servo and you can cut ground and hence you can combine those servos with ESCs.

BTW, the switches you suggest are oversized for this application with their 8A relay. If you are cutting the signal we are talking microA.
When switching the ground, we would probably not switch at full load, but the switch would need to be able to withstand the full load once switched. But one $5 miniservo and one $2 mini-toggle-switch would do the trick.
There might be miniature electronic switches that can be used if we only switch the signal - I do not know.

$80 buys you a complete 7.5 channel radio (Turnigy 9x) as such I'd aim for a lower cost alternative.

BTW2: If you operate multiple ESCs, you could instead switch the motor leads. This allows you to use fewer ESCs - which can be a very cost-effective solution.

Cheers
Jens

[fhhhstix]

Your putting more thought in to this and making it more complicated than it needs to be.

Yes the R/C switch is overkill but it will take up less space than your servo and switch and is a whole lot easier to mount.

I do agree switching the out put of an ESC would be a less expensive way but now you will need a separate switch from the others and the switch has to carry the load.

Yes there are cheap radios and servos out there but you get what you pay for. A DX6 is a good radio to use and it is less money than upgrading to a bigger radio while getting a full 8ch's of proportional control with the solutions we have discussed.

Travis

[JensR]

Hi Travis!

Two of the switches will need more space than a mini-servo and a switch.
On your criticism of being more difficult to mount: Sure, you can just "throw in" the switches, but a servo that flips a switch is not exactly difficult either.

Even if you were right on both counts, suggesting the servo solution would still be a worthwhile addition to this thread, just because of cost.

I find "my" option simpler than "yours" and so would disagree that I make it more complicated than necessary.
The only way in which I can be accused of making it more complicated is because I tried to cover all bases in one post, namely holding force needed yes/no, mixed ESCs+servos yes/no.

In summary, I am merely providing information about another option.
The OP now has two (or three) fully functioning options and can therefore make an informed decision.

The DX6 is a very nice radio - I was just illustrating the cost of your solution, especially for users of the DX5 who would not have the elegant option of installing a second receiver.

> Yes there are cheap radios and servos out there but you get what you pay for.
True. There's also the law of diminishing returns. Meaning an item twice the price will not be twice as "good". Again, it's important to be aware of the available options and make an informed decision.

> I do agree switching the out put of an ESC would be a less expensive way but now you will need a separate switch from the others and the switch has to carry the load.

That's correct. The switch you suggested would work, as it is strong enough to switch (for example) the track drive motors. Of course, the servo+switch option would be available here as well. It will depend on space&finance&preference. But again, I think it's nice to have options.

Cheers
Jens

[footprint]

Originally Posted by fhhhstix

Your putting more thought in to this and making it more complicated than it needs to be.

Exactly..and thats my job
i'll post up some pictures & ideas after tafe tonight but having it switched electronically (even with relays) i beleive is the best approach.
Ive used servo's to switch pneumatic valves and there is always something cropping up out of thin air, being it flex on the mount or having to put a ball joint on it then there is the linkage, its all a pain in the but that can be easily avoided. When you say cost, a 556 some caps, pots an AND gate and some PNP's, should come in under $10 without fudging around.

[footprint]

Ok so not the best schematics but the more i though about it the simpler it became.
These were just thrown together over dinner (its 11:30pm here) so not all that tidy ill cad up something better if anyones interested latter, but you should get the jist if you want to build it yourself.
I also snapped the servo-> valve for you Jens, I can understand where you coming from that a STDP (or STQP if your switching signals) and servo is the "easiest" solution and trust me ive done worse, eg servo's to push buttons to control hi current loads but its fiddly, at least this way it works or it dos'nt besides building this part of the board is just the beginnings, add some flipflips and you got lights, flux capacitor and you've a time machine.
anyway its late, enjoy



also quick update on the microcontroller project, am reworking the prop protocol but currently all prop 8ch's do something...sometimes.. with the lights controlled via a custom board from the GPIO's still waiting on cash for radios though.
http://youtu.be/6-SPS1VTHB0

[JensR]

Hi Footprint!

Good to read from you!
I haven't managed more with my Arduino radio than before.
http://www.youtube.com/watch?v=_Cm3TxekJO4
It works quite wonderfully, but the idea of writing my own menu system is a bit intimidating...
Maybe I'll do everything in Arduino code, but this less flexible in the testing phase.
It seems that you do this? Are you happy with it?
Plus I need to get the machine running - the current control is nice enough, so the new one is not my priority.
I have not yet learned to work with electronic _components_ like you have. :-/
Hence I wiggle my way around that gap

Regarding your servo mount: because the axes are not parallel, you get a kinematic error and possibly binding in the servohorn.
/Captain Hindsight over


Anyway, for the SPDT, you could use something like:
http://defconbots.org/defcon14/design_gun.php
http://www.ntxbg.org/pgOnTheWays/pgRadioBasics.htm
(two SPST non-latching switches)

You could use a multi-pole rotary switch:
http://www.crashed.net/~nebulous/keg/index.html

Rotating the switch?
http://www.vac-u-boat.com/FireBoat.htm

Wicked way to use a stripboard for the switch
http://www.rcgroups.com/forums/attac...mentid=3955114

If one switch isn't enough:
http://www.rcgroups.com/forums/attac...mentid=3954038

Taken from here:
http://www.rcgroups.com/forums/showthread.php?t=1426075

Another way of using two SPST:
http://www.wopba.com/controls.htm
Interesting here the warning:
""""
Do Not mount a switch to a servo
Done it and fried the servo.
When contact is made it sends a pulse that will knock out the electronics in the servo.
"""
What do we make of this?
I can't imagine this being a problem - I have plugged in servos while the receiver was powered up, without a problem.

While I find the above pretty simple, your solution would probably be my preference.
If I understood it
Whereto is RCa connected?
TP102 is a transistor?
NPN?
Should that be TIP102?
Does this work with ~1A current draw per servo?
I guess it does:
http://www.futurlec.com/Transistors/TIP102.shtml
8A?

Would using a transistor create a problem because the switching and switched circuit are then not galvanically isolated?

7404 is an inverter?
555 a timer (I knew that one!)
7408 are AND gates (I remember the shape)

So, the RCa somehow sets a value for the value that the upper AND gate compares to the receiver signal? But these can only compare 1s and 0s? So it must be a pulse-width thing? Based on the 20ms pulse of radios, and the ~1500µs servo neutral?

The inverter means that the lower AND gate will always have the other value than the upper? That ensures that only one of the transistors will be active at any moment in time. (Neglecting switching speed?)
I think some distance between switching points is needed.
You cannot have 1501µs mean channel A and 1500µs mean channel B.
Does your circuit do that? If so, how?

I guess you see why _I_ think the switch is easier

Cheers
Jens

[fhhhstix]

JensR I do appreciate the other views of how to do things. I did make an error though on an ESC you do need the ground wire to the receiver I found that out when I started running multiple ESC's in a truck and I removed the ground instead of power in the lead so I was not feeding BEC voltage from both ESC's and the ESC wont work with out the ground you have to unhook the power wire.

I did some testing today when I got home with the dual switch. I did one switching the power (red) and the other with the ground (black) and I found out that you can not switch the ground two servos receiving signal both have to have ground or neither servo works. You can cut the power with no problem. I am going to venture to say this is due to the fail safe in the Spectrum receiver.

I even made a video of the test and took some pics of the switch buy the receiver and a full sized servo so you can see the size of it compared to something of known size.

Pics





Video

Click here for the video

After the test I have decided that if he is going to use a DX6 I would just buy a second receiver and set them up as two different models 1 for driving and blade function and the 2ND for boom functions. With this you will have the fail safe active on the receiver not being used and retain holding power on those servos or ESC's.

Travis

[JensR]

Hi Travis!

> JensR I do appreciate the other views of how to do things.
Nothing more is my intention and if I learn something new, then all the better.

re: ESC and ground: Yup.

re: Your test
I don't understand that result...
Why would a fail safe system treat a broken ground wire differently than a broken power wire? Plus with the switch, it's not actually broken - it's just that one end of the y-cable's ground is not connected. Or the second servo's ground is not. Hm.
Could that be the problem? Floating ground?
Puzzling.
And disappointing.
This means that we cannot switch ESCs like this on the Spektrum, as cutting their power lead does nothing.


re: DX6: As agreed before, that's very elegant and he would know what each channel is doing as the deactivated receiver is in a known state, I think?
So, unless the receivers are very expensive - that's a nice option and even gives you 6x2 channels opposed to (6-1)x2.
Problem could be that he wants to run some lights with either model active? I don't do lights, so not sure how that would be set up.

Cheers
Jens

[fhhhstix]

I am guessing as you said before that the signal uses the ground as a reference and both servos are using the same signal then both will need the ground even though one has it the other cancels it out with out the reference. I would say the cutting the power has no effect because the servo only needs power to run the motor but that is just a guess I don't know for sure.

You can get a 6ch Spectrum receiver for $49.

I will try an ESC tomorrow with cutting the signal which I think will work because the receiver should just see it as unplugging or plugging in the lead.

Lights can be ran directly off the battery and would not be part of the system unless you used an electronic switch to turn them on and off. I power the lights on my dozer from the BEC. Since I am using a castle 20 amp BEC the draw from the 2 lights is not even a factor for the circuit.

Travis

[footprint]

Originally Posted by JensR

It seems that you do this? Are you happy with it?

Yes and no, it requires alot more planning on every step eg thinking 5 steps ahead on everything so you dont box yourself in and have to redesign.
I look it as poor mans PLC & SCADA the end plan is i should be able to monitor everything, pump pressure, temps, do trending ect and rather then mixing have set points..but im along way from there...budgets

Originally Posted by JensR

Hence I wiggle my way around that gap

Nothing wrong with that as we can see here too much knowledge is a bad thing sometimes, over complicating things just means more to go wrong. And minor mistakes in the maths that cause everything to smell like fudge.

Originally Posted by JensR

Regarding your servo mount: because the axes are not parallel, you get a kinematic error and possibly binding in the servohorn.

The valve is usually flush with the plate and secured via the 2 points at the bottom, its all in pieces while i work on the pump. The real issue is the mounting points being so low the leverage causes it to wiggle abit. One issue with your servo to switch suggestion is programming in the end limits so your not trying to drive it past the throw limits, obviously setting the horn at the right length will help but then there is the issue of leverage with microservo's vs switching loads on miniswitches.

Originally Posted by JensR

Interesting here the warning:
[I]Do Not mount a switch to a servo Done it and fried the servo.
When contact is made it sends a pulse that will knock out the electronics in the servo.

Yes that is an interesting point, I think he is referring to RFI from switching hi current loads, similar to not mounting the Rx close to the motors.

Originally Posted by JensR

Whereto is RCa connected?
TP102 is a transistor?
NPN?
Should that be TIP102?

Yes there were also several mistakes in my sch (Snr Management in my ear and the late night)
RCa is the Resistance X Capacitive circuit to set the pwm for the 555
it should have been (33x10-9 x 30.3) t= R x C
and yes TIP but TIP107, im suggesting this as it has darlington diodes built in, preventing flyback ect. and yes up to 8A and they cheap,

Yes as presented your pretty much spot on with your understanding but thats where i made a mistake, gate B should be connected to the Rx (not Tx) active not the Signal channel, meaning if the signal is ~1µs gate A is closed if > ~1µs (not A & Rx) B is closed. Im assuming a vari pot for the 100ohm in the RC to allow for adjustment but if your using the "gear" channel its either 1 or 2µs (well on my DX7 it is anyway from memory)

The sch also omits most all the resistors, PF correction/coupling and protection as mentioned id do something quick and dirty so were all on the same page, as you can see we have at least 3 different ways, That said the simplest easiest as fhhhstix presents is using the model memory and it dont get much easier then that. As i said over complicating things Thats my wheelhouse. That said if your building beacons, flashers ect your going to have spare gates, heres a use for them.

Your Ardunio is looking good, keep at it, having seen your previous controller cant wait to see it all finished.

[JensR]

@Travis
I was indeed talking about the more complicated light arrangement that people like to use. As they can get quite expensive (and sometimes large), they might want to have only one, which is active all the time. Not sure how that would be done best.

Looking forward to you ESC test. I, too, would expect the signal-switching to work.


@Footprint
Thanks for insight regarding the user-interface. I think I know what you mean by boxing-in. I have loosely planned of having the big structures (mixers, servo modes, number of channels,...) programmed in the source code, but adjusting the percentages via buttons and a menu. New world for me. Thanks also for your kind motivational words!
Good luck with your project, it seems you are coming along nicely, considering the problems you mention!


> One issue with your servo to switch suggestion is programming in the end limits so your not trying to drive it past the throw limits,

I cannot imagine going back to a non-computer radio, so I don't regard this as a problem.


> obviously setting the horn at the right length will help but then there is the issue of leverage with microservo's vs switching loads on miniswitches.

There's no need to have a huge servo-rotation. Mount the switches close to the centre-position of the servo and you do not need to take into account too much angle-deviation/leverage.

> I think he is referring to RFI from switching hi current loads

Ah, that makes sense. Yes, the electronics of the servo can act as an antenna. Still surprised that you'd fry a servo - disturbance yes, but destruction?

I must admit that I only understand half of your corrections :-/

RC - this is for the frequency of the oscillator, but I don't know how the calculation works with regards to the timing of 1ms.
Rx (receiver) instead of Tx (transmitter) is clear.
Gate B connected like Gate A, but with negator - also understood.
Varipot/trimmer -also understood
gear channel also understood - on a proportional system you might still get problems moving the stick through neutral?
I have no idea about the what and how of additional resistors and protections

I think all options presented here have their merits. It depends on what you can do skillwise, spacewise, moneywise - and timewise.
One might be able to use ready-made electronic switches - but I do not have the necessary understanding of whether these would work.

Cheers
Jens

[bigford]

so will i be able to run one ar6000 #1 or model A to run 1)steering,2)shifting,3)throttle 4)lights and 5) landing gear.
then choose ar6000 #2 or model B to run all the hydrolics all this would be on a king hauler how fast is the dx6 to switch between two models? and what would happen
to the servos and recivers from switching between???

[fhhhstix]

Originally Posted by bigford

so will i be able to run one ar6000 #1 or model A to run 1)steering,2)shifting,3)throttle 4)lights and 5) landing gear.
then choose ar6000 #2 or model B to run all the hydrolics all this would be on a king hauler how fast is the dx6 to switch between two models? and what would happen
to the servos and recivers from switching between???

The DX6I is able to switch between models rather quickly and the receiver that is not active will go into fail safe and hold the positions that were set when the receiver was bound.

Travis