EthOS Tips and Tricks

[Nathan]

The microphone on the transmitter is designed for outputting sound files from the transmitter. I have no idea if there is a way to get audio through the telemetry signal. You'll need to call FrSky to figure that out. But I am very doubtful.

I hope you can get it working though!

Nathan

[NicholasRadzykewycz]

[QUOTE=He Who Shall Not Be Named;n189879]

You want real-time passive sonar from your model submarine. No problem.

Yes, I'm using a pair of Glady's hydrophones positioned at roughly 22 inches apart, so there will be enough lateral distance to get some better angle bearing with the increased speed of sound in water. Boat is being designed from the ground up for silent running, so special ESCs, Motors and Servos all ultra quiet as well as rubber cushion on every mounting bolt for further isolation.

Already have a working 900 Mhz transmitter for audio which seems to work decently. It is however very bulky and takes up a significant amount of hull room. I was mostly just noticing the port on the FRSky for headphones and the fact it played audio made me wonder if EthOS could save me a bunch of trouble of an independent transmitter and allow for audio on a single antenna system.

Boat will also be equipped with an active sonar as well in the form of a Deeper Pro castable fishfinder with a modified extended antenna. This will only work on the surface and at periscope depth

Underwater navigation to be achieved with a compass module for the FRsky.

I plan on running the sound eventually to an analyzer software on shore for more precise sound localization


The purpose of this sub is for wargaming, but more importantly the sound function will help a lot with submerged navigation, since I can visually look at the boats on the water and figure out where I roughly am at by listening to the other boats. This also allows for using things like fountains or any other fixed underwater noise source as a nav beacon so that I can puzzle out my location if I lose track of my boat underwater without having to surface and reveal where I am at.

[He Who Shall Not Be Named]

Working on a project where I'd like to send audio from a pair of microphones thru the FRSky antenna and was wondering if anyone had done that before or how to set it up in EthOS. Might have to be a custom function to write but I could save an entire large and bulky second signal antenna in my sub and reduce interference if it is possible to send audio via the FRsky

You want real-time passive sonar from your model submarine. No problem.

I did that back in the day with a little FM transmitter mounted within the forward bulkhead of my 1/96 SKIPJACK's WTC.



Self noise was a problem, so I would sit on the bottom -- no aboard motor or servo noise getting in the way -- and listen. Only useful dope I got from the radio head-phones was kind-of-sound, amplitude, and doppler. No bearing or range, of course. But I could tell, without looking at the water, who was sniffing and how close they were.

You talked about two microphones/hydrophones. You're looking for relative bearing, right? The brain is not quick enough to tell the time differential in water, so you'll need an H-type detector to present bearing to you through a display. However you'll make out the amplitude differential by feeding one channel into one ear, and the second channel into the other -- that should be enough for you to skull out a rough relative bearing in real time.

My little effort was accomplished in the late 80's. With that gear no one snuck up on me!

David
High School Dropout

[NicholasRadzykewycz]

Working on a project where I'd like to send audio from a pair of microphones thru the FRSky antenna and was wondering if anyone had done that before or how to set it up in EthOS. Might have to be a custom function to write but I could save an entire large and bulky second signal antenna in my sub and reduce interference if it is possible to send audio via the FRsky

[biggsgolf]

Nathan, this is much appreciated!

[Nathan]

Mixing Planes with Rudder to Reduce Pitch/Roll (For roll you must have the ability to control each side of the dive planes independently. The differences needed for pitch-only are included as well, towards the bottom.)

This one is a little more complicated and I don't have a boat that I can fully test this on. The exact weights and directions will have to be left up to you. I'll highlight areas where those changes can be made, but the specifics will be up to your individual boat and preferences. I suggest you make sure your output limits are set to prevent any damage from over travel and use the full values in my pictures. This will show you an exaggerated version of the changes. That will help you set up the directions of the inputs and otherwise make the secret sauce less secret.

Okay, here we go:

Set up a curve to use for mixing in the throttle. This curve is set up to only start working when the boat is moving forward. If you don't have reverse, or want the throttle's impact to start at a higher throttle then modify this curve. Most likely you won't want it to go to 100% unless you have a really large and slow moving boat. There is nothing fancy in this curve otherwise so I am not showing the config page. Do note that the curve starts at 0, not -100 - this is because 0 should be no throttle and negative is reverse. Sorry, I am not going to document how to make this work while travelling backwards!



Set up a logic switch to only activate in more extreme rudder movements. I am thinking that tiny movements of the rudder will not cause significant rolling so this logical switch sets up where in the rudder stick travel to turn on the anti-rolling function. The value (x) percentage is setpoint. The absolute value function ensures it works on both sides of the rudder input.



Create an output for our throttle mixing. This output is what links the speed of the model to the amount of correction. The "control' of this amount is through the Curve. This is just a necessary intermediary because of the way EthOS works. Make SURE you use a channel that does not have anything plugged into it. EthOS doesn't care if you use a channel above the count on your receiver. This channel NEEDS to be greater than the number of channels on your receiver. I chose 5, but you could use 10 or even 64. Just use a channel that is not physically connected to your model. The mix we will create will make this channel function.



Add the Throttle Mix. This mix ties the throttle stick (or pot, or whatever you use) to our fake output (Channel 5 for me, maybe 10 or something for you - again, a channel you are not already using. Don't break your model)




Make sure you apply the Curve and set the channel. The source is the same as you use for your throttle.

And, finally, make the anti-roll mix. This is the mix that moves the planes according to the amount of rudder and throttle. it isn't complicated once you get this far. There is a trick in the Actions, though, you have to "long press" to get the ability to choose the channel.


Here is the Action screen with a highlight for where to long press. When you do so, a screen will popup and offer a selection of "Use a source". Choose that and then select Channels and your Channel

Okay, the rest of the mix:

Note that I chose BOTH of the planes. Here is place where you might need to reverse one to get the direction of travel you need.


For pitch-only control

Use this curve instead:



And add it to the Throttle mix


That was even easier that I thought it would be!



From here you will just need to play around.

I am planning on bringing my test rig to Subfest (2024 Redux) if you'd like to try it out in person.

Nathan

[biggsgolf]

Biggsgolf, I haven't used stability control on a sub yet, others have and might chime in.

Regarding roll control, assuming you have each plane on an independent servo, you can mix the roll into the rudder mix. And if you add in some throttle mixing.... Bob and I have discussed this sort of mix but I haven't been able to experiment. I'll spend some time on it this week and see if I can get something posted this weekend.

Nathan

Thanks Nathan!

[Nathan]

Nathan, great posts, have you come up with or seen how to use the Flsky XR18 pitch control? I also want to figure out how to program for the Planes to offset each other to stop sub listing in turns, any idea about that? Thanks Nathan

Biggsgolf, I haven't used stability control on a sub yet, others have and might chime in.

Regarding roll control, assuming you have each plane on an independent servo, you can mix the roll into the rudder mix. And if you add in some throttle mixing.... Bob and I have discussed this sort of mix but I haven't been able to experiment. I'll spend some time on it this week and see if I can get something posted this weekend.

Nathan

[biggsgolf]

Setting Up Ballast Control Using the 6-Position Switch

If anyone wants to use the 6 position switch as momentary switches to control your ballast with 3 different modes, this should get you started. In this example we are using the left most set of buttons to control three ballast actions:

• Venting the tank (actuated by a switch driving power to a solenoid)
• Normal blowing of the ballast (actuated by opening the valve for surface air and powering the air pump)
• Emergency blow (actuated by powering the air pump only)

NOTE: opening the vent and turning on the air pump use the same channel (a dual relay board driven by a single receiver channel)
NOTE: this is a system that scavenges air from the dry compartment for emergency blow with a valve to allow surface air in for normal blow

To start, set up a state table like this showing the states of the channels you need (this case has 2 channels, but yours may have 3. Even more could be possible by extending this example.)

Switch	Action	Channel 1 (surface air valve)	Channel 2 (Air Pump & Vent)
Upper (FS1)	Snorkel Blow	-100	-100
Middle (FS2)	Emergency Blow	100	-100
Lower (FS3)	Vent	100	100

This table will help you be sure you are setting the right values at the right time. Be sure to test each value to be sure (we had swapped the pump and vent and nearly burned up a solenoid because we were driving it when we thought we weren't!)

Once you have your state table set up we need to configure the transmitter 6-position switch. This is a 2 step process.

The first step is to tell the transmitter how to treat the switch
In Edit Model set the "Function Switches" to "Momentary" - this makes each button an independent momentary switch (this transmitter is awesome!!)


Now that we have 6 more switches we have to set up Variables to actually use them. For this set up we'll use 3 vars, one for each button.
We are going to work our way from the bottom of our state table to the top because venting and emergency blowing is "easier" because they each impact only a single channel.

The Range isn't critical in our setup, but be sure it includes the values you are setting. The Values section:

• Sets the default value (-100)
• We added the FS3 switch which sets the value to 0
• (for THIS setup, we need a default value of -100, your model may be different)

In operation, the value will be 0 until the switch is pressed. And it will be 100 as long as the switch is down.
Now we'll repeat 2 more times.


These variables now become the "switches" in our mixes

Vent Mix - actuating the venting solenoid



Pump Mix - actuating just the air pump



And finally the slightly more complicated state, the Snorkel Blow both opens the valve and actuates the pump
So this is actually 2 mixes actuated by the same switch. (okay, not ALL that complicated...)
We start with opening the valve



And then we turn on the pump



And that does it.

Of course your exact values, channels, and output reverses may differ, but the idea can be applied across many functions.

Nathan

Nathan, great posts, have you come up with or seen how to use the Flsky XR18 pitch control? I also want to figure out how to program for the Planes to offset each other to stop sub listing in turns, any idea about that? Thanks Nathan

[Nathan]

Setting Up Ballast Control Using the 6-Position Switch

If anyone wants to use the 6 position switch as momentary switches to control your ballast with 3 different modes, this should get you started. In this example we are using the left most set of buttons to control three ballast actions:

• Venting the tank (actuated by a switch driving power to a solenoid)
• Normal blowing of the ballast (actuated by opening the valve for surface air and powering the air pump)
• Emergency blow (actuated by powering the air pump only)

NOTE: opening the vent and turning on the air pump use the same channel (a dual relay board driven by a single receiver channel)
NOTE: this is a system that scavenges air from the dry compartment for emergency blow with a valve to allow surface air in for normal blow

To start, set up a state table like this showing the states of the channels you need (this case has 2 channels, but yours may have 3. Even more could be possible by extending this example.)

Switch	Action	Channel 1 (surface air valve)	Channel 2 (Air Pump & Vent)
Upper (FS1)	Snorkel Blow	-100	-100
Middle (FS2)	Emergency Blow	100	-100
Lower (FS3)	Vent	100	100

This table will help you be sure you are setting the right values at the right time. Be sure to test each value to be sure (we had swapped the pump and vent and nearly burned up a solenoid because we were driving it when we thought we weren't!)

Once you have your state table set up we need to configure the transmitter 6-position switch. This is a 2 step process.

The first step is to tell the transmitter how to treat the switch
In Edit Model set the "Function Switches" to "Momentary" - this makes each button an independent momentary switch (this transmitter is awesome!!)


Now that we have 6 more switches we have to set up Variables to actually use them. For this set up we'll use 3 vars, one for each button.
We are going to work our way from the bottom of our state table to the top because venting and emergency blowing is "easier" because they each impact only a single channel.

The Range isn't critical in our setup, but be sure it includes the values you are setting. The Values section:

• Sets the default value (-100)
• We added the FS3 switch which sets the value to 0
• (for THIS setup, we need a default value of -100, your model may be different)

In operation, the value will be 0 until the switch is pressed. And it will be 100 as long as the switch is down.
Now we'll repeat 2 more times.


These variables now become the "switches" in our mixes

Vent Mix - actuating the venting solenoid



Pump Mix - actuating just the air pump



And finally the slightly more complicated state, the Snorkel Blow both opens the valve and actuates the pump
So this is actually 2 mixes actuated by the same switch. (okay, not ALL that complicated...)
We start with opening the valve



And then we turn on the pump



And that does it.

Of course your exact values, channels, and output reverses may differ, but the idea can be applied across many functions.

Nathan

[Nathan]

Just wanted to get some clarifications on this feature, it appears that one of the screenshots is missing. Any chance you could repost it? Just wanted to know the logical switch settings in EthOS.

Thanks!

Sorry that picture didn't come through. I recreated it because I couldn't find the original.

Someday I need to figure out why the forum won't email me when people make a reply...

Nathan

[rwtdiver]

Should be just the thing, Rob! You can either have it all on one stick or separate them into two. Completely up to you!

I see your point, Bob! I am going to try that set up next. I can see where it might be a smoother operation having both on one stick...

Thank you for your input..

Rob
"Firemen can stand the heat."

[neitosub]

OP doesn't seem to be active on this forum anymore, so here's the answer to my question earlier in case anyone is looking for how to set up the bow plane lock out:

https://youtu.be/sFWZYyOZXsI?si=M_OD1JErUR63Ll2B

It's pretty much like the video above, the functions we are looking for are similar to the nose landing gear steering lockouts in RC airplanes.

[neitosub]

Bow Plane Retract Lockout

IMPORTANT: before testing this be sure you have disconnected any linkages that could cause damage if anything goes wrong, or if any outputs need to be reversed.

When you have retracting planes it is important to be sure of 2 things. One, that the planes will centered before they retract, and two, that they cannot be operated while retracted. If you have an EthOS radio you can set this up right in the radio. Here is how.

There is one thing that it is important to note about EthOS in order for this to work - EthOS only tracks the "sweep" of a channel if there is a slow set in the mix. If you don't use a slow you will see the channel move direct to the endpoint (for example, 100% right to -100%) even though you see the servo is still moving. With the slow enabled, EthOS, and you, will see all the values (for example, 100% to 98% to 96%, etc.) This sweep is important because it keeps the logical switch in time with the retract servo. Though if there is a mechanical problem with the servo the radio won't know. A closed loop system will have to be left up to the Reader, sorry.

Okay, here we go.

Planes Enabled Logical Switch
You first need to create a Logical Switch to identify when the planes are enabled. Note that the source is the retract servo channel. That is the "sweep" we need. The delay gives a second for the servo to finish deploying the planes before activating the planes. It should be a "just in case" but your physical configuration may require a longer delay before becoming active.



You will use this logical switch in the planes mix.

Planes Mix

Note the active condition is the logical switch, meaning the planes can only move when the logical switch is on. When the active condition is false the channel is set to 0, which is centered position (works well for us!) Be sure you factor in the logical switch if you add extra mixes for the planes.



Retract Mix

Finally, you need the mix for the retract channel. This is where the slow goes.



You will have to reverse the channels, maybe adjust the slow on the retract mix, or the delay on the planes mix, but this should get you on the right path.

Nathan

Just wanted to get some clarifications on this feature, it appears that one of the screenshots is missing. Any chance you could repost it? Just wanted to know the logical switch settings in EthOS.

Thanks!

[trout]

This is a great thread. This will be a reference I will be visiting over and over.