Remote Control thoughts

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ChipsAhoy
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Re: Remote Control thoughts

Post by ChipsAhoy »

I have no idea how it is done, but....
I saw on the news the other day a fellow demonstrating a drone substitute for fireworks. Somehow he had what seemed to be a hundred of those little guys doing intricate aerobatics in unison. So, some place, some body has multiple receivers working in unison.... suppose they have the same number of transmitters going at the same time? If so, those transmitter are "receiving" in unison.
There, spoke my piece, now I've got to go fix a hydraulic leak where my two axle motors are receiving variable flow from this single leaking 20 lb hydraulic valve!
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Gra2472
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Re: Remote Control thoughts

Post by Gra2472 »

Ugh hydraulics. I took a spectacular bath on a Kubota backhoe a couple of years ago when the bucket loader lift cylinder line burst. I think I still stink like old hydraulic oil.
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Dick_Morris
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Re: Remote Control thoughts

Post by Dick_Morris »

Do the systems you are looking at have a spring loaded return to off position? If not, and maybe even if so, a separate dead man's switch might be a good feature.

I'll have been married to the lady who lets me live with her for 53 years next week and been her primary caregiver for at least last 20 since she has been in a wheelchair. One thing I've learned with assistive devices, try and stay a couple of steps ahead of the progression instead of just accommodating the status quo.
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Bill Shields
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Re: Remote Control thoughts

Post by Bill Shields »

again - these are radios designed / licensed for aircraft use and should not be applied to anything on the ground.

a few years ago, a diesel / hydraulic loco at one of the clubs i frequent -. was sitting at the station, idling...when it took off all by itself with nobody aboard.

we were all but ready to dump it into shunt it to the turntable steaming bay pit as it was getting faster and faster as it came around the track.

FORTUNATELY, it derailed before it got to our 'trap', and someone was able to get to it and shut off the engine.

The club took a very hard look at 'unattended' but 'running' anything....

IIRC the cause of the problem was a self-centering spring on the forward / reverse hydraulic valve failed and the valve went 'off center' causing it to begin to 'drift' forward at an ever increasing speed.
Too many things going on to bother listing them.
Gra2472
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Re: Remote Control thoughts

Post by Gra2472 »

I want to make it perfectly clear that I am NOT using an aircraft system. Flysky is simply a brand of low cost RC receivers and transmitters. The one I am using is a relatively generic system for rc cars.

The throttle is a self centering trigger type. pull back like a gun and you go forward, push away for reverse, let go and it stops. If the receiver stops receiving a signal for any reason, it stops. If you deliberately turn the transmitter off, or remove the batteries it stops. I tried all of these scenarios several times to ensure that it works. However, the method I am experimenting with for MU capability has some inherent safety issues that I have to address, unless I can find a method of sending a PWM signal through the consist for throttle control. With a clear PWM signal, control of the locomotives is absolute and quite safe.

The steering wheel is the same and I've played with it as a throttle input. It works, but its not intuitive. It does work well for the horn however.
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John Hasler
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Re: Remote Control thoughts

Post by John Hasler »

Don't worry about it. If you can buy it off the shelf without a license it's legal for your application. The same radio rc systems are used for hobby rc model aircraft, rc model boats, and rc model cars. The FCC intends for these systems to be used for whatever. They are very low power and do not share frequencies with anything the failure of which could endanger anyone.
Gra2472
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Re: Remote Control thoughts

Post by Gra2472 »

That's good to know, thanks John.
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The railroad is almost done.
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Bill Shields
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Re: Remote Control thoughts

Post by Bill Shields »

I beg to differ.

Anyone with money can purchase a transmitter Intended for use with a radio controlled airplane...no specific license required.

Other than common sense, nothing prevents you from using it on a ground system.

Look up FUTABA and see what they sell. None require any special license.

Out local flying club is constantly plagued by idiots using aircraft radios to control cars.
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Gra2472
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Re: Remote Control thoughts

Post by Gra2472 »

Since there seems to be some concern about radio control interference as Bill has mentioned. I think it would be fair to talk about what I discovered in researching the 2.4ghz rc system that I am using. I am not an RC guru, so I dug into it and found some specific information. While this is slightly off topic for Riding Scale Railroading, since my original post was about RC control of my locomotives I will proceed. I hope that this will be helpful. Hey, we all should learn something new everyday. Unfortunately I often forget something to make room. Now where was I going with this...? Oh yeah, education!

Below is an excerpt from an article I found that seems to have the simplest explanation of how the system works. The system I am using is 2.4GHz which requires the transmitters and receivers to be bound together, and I can attest personally that once bound, they cannot be interrupted.

Forgive me, but I am not going to use MLA or Chicago citations :-)

https://www.rc-airplane-world.com/bind-n-fly-rc.html

The binding of receiver to transmitter is a fundamental part of flying on a 2.4GHz system, the process enables the Rx and Tx to lock together to form the impenetrable signal that has made spread spectrum radio systems so reliable. The binding process varies slightly between manufacturers but it's a simple process that is quickly done.

The Spektrum binding process should be carried out as per your Tx instruction manual, but essentially it involves inserting the supplied bind plug (shown right) into the appropriate receiver slot, powering up the receiver and then switching on your Tx while activating the bind function.
The Tx and Rx will then communicate with each other and bind after a few seconds; successful binding is indicated by the flashing orange LED on the Rx turning to a solid illumination. Once bound, you shouldn't need to do it again for that model although you can re-bind the two components at any time, for whatever reasons.

During the binding process the receiver learns the Global Unique Identifier code (GUID) that was programmed into the transmitter during manufacturing. There are 4.2 billion code combinations possible and this is one of the reasons why spread spectrum rc technology is so secure.


Here is another article that suggests clearly that the same 2.4ghz radios can be used for combat robots, which unless I am mistaken, do not fly.

I took this excerpt from https://www.soinc.org/sites/default/fil ... tsFAQs.pdf

Sumo Bots are required to be designed so they can be operated on three different frequencies. This can be three sub-frequencies of one frequency (for example, 27 MHz, channels 1, 3, and 5) or a combination of different major frequencies (example: 49 MHz, Channel 2 and 75 MHz, Channels 63 and 72). As long as you can change the frequency your bot operates under among three different frequencies (or sub-frequencies), you have met the rules. If you are using the 2.4 GHz frequency, then your bot will automatically switch to an unused frequency, so there is no need to worry about the three frequency requirement. However, you need to be aware that if your transmitter cannot find an available channel (for example, if 80 people in the crowd have Bluetooth enabled cell phones turned on) then it simply will not transmit until a channel becomes available

I can point to several different articles that I have read in the past few hours, but I cannot find a single specific mention of 2.4ghz aircraft controllers being prohibited for use in cars, boats, or in our case trains. I have found several model airplanes, boats, and cars that all use 2.4GHz control for sale on various sites including Amazon. I would also like to point out that 2.4GHz is also known as Bluetooth! Well whatya know.

It is still true however, that the 72MHz band is specifically reserved for model aircraft, and using a 72MHz radio for ground based RC is illegal.

Thanks for the lively discussion!

G
Last edited by Gra2472 on Sun Jun 20, 2021 3:06 pm, edited 2 times in total.
7.5" Allen Mogul
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Bill Shields
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Re: Remote Control thoughts

Post by Bill Shields »

Absolutely true. There are however a lot of non Spectrum units out there that can be interfered with.

The one deawback to these units is that if you should lose 'lock' between transmitter and receiver-> it can take a few seconds to reestablish the link...during which time all servos are fixed at current position.

Does not sound like much unless your aircraft happens to be pointed toward the ground at the time.
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kcameron
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Re: Remote Control thoughts

Post by kcameron »

One worthwhile thought is a safety on the loco. I know one loco that is radio operated sometime that has an external kill switch. It looks like a small stack on top of the loco. Hitting it down or pulling it up will activate a battery disconnect. The idea is a safety you could run up and grab/hit should something go very wrong with the radio control.

The other type of safety I've heard of watches for the control signal and returns to off the servos if it gets the signal interrupted. I'd presume it has a very short timeout to avoid momentary signal issues.
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John Hasler
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Re: Remote Control thoughts

Post by John Hasler »

"Stop on loss of signal" should always be there.
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