Setting up IO-D/E to drive a servo?

[A VIKING]

Feeling mentally challenged...
I would like to use the IO-D/E port on my SK720BE to drive a servo.

I have assigned an AUX4 function to my "D" toggle switch in my DX-9 and can see on the servo setup screen of the DX-9 that the "D" switch does control AUX4 on the display.

How do I get the SK720 to recognize that signal to control the servo connected to IO-D/E?

I am setting up my Velos with a controllable cargo hook I built to have some long line sling load fun.

[georgi UK]

Martin hello buddy!

On it's own, the 720 D/E port is designed for power bus use which splits the 2 signals (top & middle pins) into dedicated ports by way of the jumper cable.

If you don't want to use the bus? we can do a work-around for you,,,,,,

cheers, georgi.

[A VIKING]

Originally Posted by georgi UK

Martin hello buddy!

On it's own, the 720 D/E port is designed for power bus use which splits the 2 signals (top & middle pins) into dedicated ports by way of the jumper cable.

If you don't want to use the bus? we can do a work-around for you,,,,,,

cheers, georgi.

Hey Georgi!

I never used the power bus on any of my SKs but if you remember years back I did try to run power into that plug...and as I found out, that's not a good idea.
So IO-D/E and I have a bad history together and it would be great to understand it and make it useful.

If I can make the IO-D/E drive a servo, that would be all I need unless you tell me I need the power bus to do it right, but that would cause me to redo my harness...but if it would be an advantage I would do it.
Just trying to keep it simple, fewer connections fewer possible errors.

What would the work around be?
Thanks for the rescue!

[dcope17]

I don't have any Skookum 720s anymore to test this, but ( I believe ) you get the power + and - from a different port than the D/E and you'll only hook the signal wire to a pin in that port. Similar to doing a 6 servo tandem wiring.

[georgi UK]

Martin, yes, I remember that scenario well, fun-n-games!!

As said above, use only the signal pin. Which is the (Red) centre pin for channel 'D' and power the servo independently.

The exception can be?, as the ports were becoming saturated for the many types of Rx the 720 could accommodate, SW-A port would be used prior to IO-DE. so that's worth knowing!

[A VIKING]

Originally Posted by georgi UK

Martin, yes, I remember that scenario well, fun-n-games!!

As said above, use only the signal pin. Which is the (Red) centre pin for channel 'D' and power the servo independently.

The exception can be?, as the ports were becoming saturated for the many types of Rx the 720 could accommodate, SW-A port would be used prior to IO-DE. so that's worth knowing!

So IO-DE doesn't follow normal pin out for a servo connection which would be the top wire or white/orange wire being the servo signal or control wire and the red and black wires being power connection.

So I should still use the red (center) pin, IO-D, on the SK to supply the controlling signal to the servo and power the servo directly from my RX battery.

The orange pin would be another servo signal connection, IO-E?
...that would make the black pin be used for what?
Don't tell me the SK720BE can drive 7 servos on my Velos 880 or my mind will explode. Wait a minute, the manual says it can drive 10 servos...BOOM!

I imagine they are talking about the 8 normal ports on the SK with IO-D/E being ports 9 and 10?

Teach me master!

[A VIKING]

I am still missing something to allow a functional servo being driven by IO-D, or the middle pin coming out of the SK from the IO-D/E port.

I made up a simple harness with the middle pin on IO-D/E to feed the top wire or white/orange pin (signal) on my servo plug.
The other two wires, black and red from the normal servo harness are connected to a RX battery to power the servo.
Only the middle pin is connected on the SK at IO-D/E.

My DX9 has been programed to allow AUX4 output to be controlled by the "D" switch on the TX. This can be seen to function on the "monitor" screen.

What needs to be set up in the SK?
There are drop down boxes for the AUX ports available but they all have functions assigned to them that control various gain settings and GPS functions.

What's the secrete? How do I get my TX to talk with a servo other than the flight servos on my model?
I am missing something but don't know what it is...any help, I would appreciate it.

[georgi UK]

Hey! This is what I (poorly?) referred to earlier. In that the SK uses internal switch-able ports. So depending on the control panel radio selection, different ports will offer different outcomes,,,,,

If you work on the logic where alphabetically > any live Tx assigned channel will then be available at the next open port. Use the channel end-points to operate,,,,,

In your case, Aux 3 or 4 is set in the control panel 'not-used' and then 'go fishing' for the 720 signal!

Start with SW-A and work towards IO-D. All signals will be upper pins apart from IO-D, and yes IO-E is the next available channel at the top pin.

So to iterate as it reads-back like a bag of crap to me! if you have occupied an open port with power etc,,,, the 720 could be sending a signal to that port and isn't aware a connector is fitted,,,,,, keep at it please!

[A VIKING]

OK...so I have a sixth controllable servo on my Velos 880 to operate my cargo hook which I can now design and build.

The additional servo to the SK720BE is not connected to IO-D/E like I had thought it should be but it is connected to IO-B.

IO-B was my primary RX battery connection and I have a secondary RX battery connection soldered into one of my primary flight servo power leads.

All I need to do is solder the primary RX battery connection into the added servo power leads connected at IO-B and I'll be back to dual power leads into the SK and have an additional servo to play with.

So my take away from this is (and as georgi stated above) that the SK720BE is very linear in logic with it's connections.
IO-B had RX battery connections to it but the signal wire was unused.
I tried to use IO-D/E for my project but couldn't get a signal to the added servo from either D or E.
I had to back up to the next available port with open signal pin which was IO-B....AND set my channel to control this port in my DX9 to AUX3 and not AUX4 like I had earlier.

I did try to connect another operable servo to IO-D with the added servo connected to IO-B to see if I could get it to drive and I only got a slight amount of movement in the servo during initialization but that was it.
Since I have an additional servo working from IO-B my project is off and running so I will forget about IO-D/E for now.

[georgi UK]

Good work there Martin! shout when you want more channels,,,,,

cheers, g.

[Luvmyhelis]

Ahh, cargo hook! Wondered what new cool idea you were working on. I beg for a vid!

[A VIKING]

Thanks Georgi and LMH!

I just started the thread about this saga over on the Velos site.
Come visit to see the cargo hook story, photos and eventually video of it in action.
https://www.helifreak.com/showthread.php?t=777285

Should be fun!

[georgi UK]

It's more clear to me now what you are developing there Martin, initially I thought this was a winch of some description using a dedicated yacht sail drum type servo?

Where it seems, you will be 'fishing for a loop' (get your hat!!) and can then jettison the payload as and when?

Personally I favor the over centre type latch,,,,,,,,,,,

[A VIKING]

Originally Posted by georgi UK

It's more clear to me now what you are developing there Martin, initially I thought this was a winch of some description using a dedicated yacht sail drum type servo?

Where it seems, you will be 'fishing for a loop' (get your hat!!) and can then jettison the payload as and when?

Personally I favor the over centre type latch,,,,,,,,,,,

...and that's why I post lots of photos...

This is just a simple sliding pin to secure and then release the load if or when necessary.

I should have taken a video of the load testing. With 52 pounds hanging on the hook and then hitting the release switch the truck tail gate it was sitting on would rebound up when the load dropped.
Can't imagine what that would be in flight.

...a winch....hummmm...now you got me thinking again.

[Keyrigger]

If you're intention is to drop a load from the hook as opposed to placing it on the ground before disconnecting, you WILL pop like a cork. When I drop the two pounds of water from my bucket through the opening in the bottom, it does rise in the air if I don't reduce collective slightly at the same time. Good luck with the hook.

Don

[georgi UK]

Another channel/servo could be needed as the beast evolves! This application has a valid need for the GPS 'lock grid'. as you are steering the hook axes, not the heli, it should also manage the hold altitude for changes in abrupt payload changes, although at the current refresh rate, not seamlessly,,,,,,,

I would also be wary of reflex inputs that (given the power you have available) increase the G ballast loads.

To explore things further Martin, these switch-able magnets offer positive fail-safe, which you may be interested in? a choice of strengths etc,,,,

http://www.first4magnets.com/magnet-...9714#ps_1-9981

[A VIKING]

Thanks Keyrigger, I'll be looking for the "pop" on load release.
I will be starting out with light loads for practice and exploring what kind of amp loading I am imposing on the system when flying.

Georgi..."as the beast evolves", yes indeed, to where and to what extent, that I don't know yet but it's exciting thinking about the new possibilities.

GPS will come in the future most certainly as will video.
Just learning to walk before I run.

Thanks for the tip on those switchable magnets, more idea driving technology for sure.

Looking forward to my first flights, steady as she goes, nothing drastic to start, but if things get crazy, I can always drop the load.
Weather has been crappy and I need to work so those initial flights will have to wait for now.
Gives me time to think it through, which is always a benefit.