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Author Topic: HELP FAILSAFE FOR A 2.4 GIG R/C  (Read 1572 times)

JimG

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Re: HELP
« Reply #25 on: August 25, 2020, 12:20:22 PM »

One question that hasn't been asked yet is where do you have the receiver aerial/s mounted. ith 2.4GHz it is important to mount them above the water line, the higher the better.
Jim
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Akira

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Re: HELP
« Reply #26 on: August 25, 2020, 12:46:14 PM »

After market failsafes are available and it sounds like this may be the easiest and safest way to go, in this instance. It used to be standard to add a failsafe to the throttle and the rudder servo circuits on when using the older radios. Now with new computer radios, folks take it for granted that it will be taken care of for them. Not So!.  If your radio does not offer the option of a failsafe that is not forgotten, then fit one. They fit inn line between the servo and the receiver and take no room at all and weigh nothing.
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C-3PO

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Re: HELP
« Reply #27 on: August 25, 2020, 01:01:21 PM »

Many modern 2.4Ghz receivers will output a "valid" RC PWM signal in the event of loss of reception from the transmitter - the issue is the "valid" output may not be what you want which would most likely be a neutral, mid stick output (1500ms) for a ESC that has forward and reverse.

This would fool an external "fail safe" black box unless it was monitoring frame rate which tends to go AWOL with loss of signal from a transmitter or perhaps the time since the last PWM signal last changed - I have my own "fail safe" which do both but not sure commerical products work this way.

Some receivers will output your "preset" value, some just continue with the last "valid" one, some just start free running and jump all over the place


C-3PO
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Captain Flack

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Re: HELP
« Reply #28 on: August 25, 2020, 01:08:52 PM »

On some makes of TX the "fail safe" is set to whatever position the throttle stick was in when it was bound. 
Obviously on a boat that should normally be  in "center" position or neutral.The problem that can be found is that, when you switch on, the radio gives you an alarm that the stick is in the center position and won't activate until you return that stick to full off, or full astern in our case.  Remember these radios are generally geared for aircraft not having a reverse.Consequently when bound you are binding at full astern, and not neutral as you perhaps thought.Ask me how I know :(( :(( :((
I don't know of a TX that sets the fail safe, every time you turn on. That is surely fraught with danger, as you won't know where you're at. :-))   You don't bind the TX/RX every time you turn on.

 
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Akira

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Re: HELP
« Reply #29 on: August 25, 2020, 02:03:34 PM »

"Many modern 2.4Ghz receivers will output a "valid" RC PWM signal in the event of loss of reception from the transmitter - the issue is the "valid" output may not be what you want which would most likely be a neutral, mid stick output (1500ms) for a ESC that has forward and reverse."
Thanks for posting this. It is new to me, but then I have been a 75mhz addict for years and just moved to 2.4ghz. Fortunately my 2.4 radio allows for custom failsafe settings for all channels.
The continued output of a "valid" signal in the event of a true signal loss sounds like a plan by manufacturers to get you to buy more models...and radios. It probably isn't, but it is a problematic design. I guess that it pays to read up, carefully, before buying a radio, if you want to keep your boat, for some time that is.
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C-3PO

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Re: HELP
« Reply #30 on: August 25, 2020, 03:14:34 PM »

I have been working on a project for a while - one aspect of that project would be ideal to diagnose exactly happens to the receiver output when it looses contact with the transmitter.

The initial brief was to have a "snazzy" servo tester but I extended the concept to also read the receiver output.

It uses any "WiFi" enabled browser device - e.g. smart phone, tablet etc.

Here is a sneak preview of the receiver output displayed on my iPhone screen

https://www.youtube.com/watch?v=f9C_GG0x0Fc



https://www.youtube.com/watch?v=f9C_GG0x0Fc

Regards
C-3PO
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Martin [Admin]

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Re: HELP FAILSAFE FOR A 2.4 GIG R/C
« Reply #31 on: August 25, 2020, 04:35:44 PM »


Topics merged
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frogman3

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Re: HELP FAILSAFE FOR A 2.4 GIG R/C
« Reply #32 on: August 25, 2020, 08:10:54 PM »

OK THANKS GUYS looks like a bag of mixed answers  so i'll see what the chap in my model shop recomends
all best to you all
chris
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Bob K

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Re: HELP FAILSAFE FOR A 2.4 GIG R/C
« Reply #33 on: August 25, 2020, 09:25:23 PM »

You have to remember that such radio control is designed for aircraft.
When an aircraft loses signal the best "fail safe" option is to centre flight controls and turn the motor off.
The plane will lose altitude and hopefully come down somewhere you can recover it.

I always set fail safe to OFF for boats.  Not a lot you can do except hope someone lakeside has recovery push tug to get it back to shore.

Unless of course C-3PO can devise something very cunning  %%
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frogman3

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Re: HELP FAILSAFE FOR A 2.4 GIG R/C
« Reply #34 on: August 26, 2020, 07:29:48 AM »

You have to remember that such radio control is designed for aircraft.
When an aircraft loses signal the best "fail safe" option is to centre flight controls and turn the motor off.
The plane will lose altitude and hopefully come down somewhere you can recover it.

I always set fail safe to OFF for boats.  Not a lot you can do except hope someone lakeside has recovery push tug to get it back to shore.

Unless of course C-3PO can devise something very cunning  %%


HI  Bob yea it may be like that hopein somone will stop it from hittin the concrete side of the pond but im just as worried in case my ship hits an sinks someone eles model as i always take extra care when sailin to be sure i always miss others an when the guys come on with their big yachts sometimes i just dont know which way they will go as they are tackein to catch the wind but i dont want to be put off this hobby as im retired an i have no intreset  in any other hobby an its quite embarrasin if you have a nice model an then it hits the wall in front of loads of holliday makers as at time there is qiute a few all watchin the boat on the water
chris
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frogman3

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Re: HELP
« Reply #35 on: August 26, 2020, 08:07:58 AM »

One question that hasn't been asked yet is where do you have the receiver aerial/s mounted. ith 2.4GHz it is important to mount them above the water line, the higher the better.
Jim
AN HI Jim well to answer your question on where the r/x is mounted its right in the bow area mounted just under the deck under the 4.5" gun an at that point the r/x is about 4 inches above the water line so signal pick up should not be a problem
chris
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jaymac

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Re: HELP FAILSAFE FOR A 2.4 GIG R/C
« Reply #36 on: August 26, 2020, 09:37:38 AM »

Are you are talking about the  failsafe in the Esc  or a dedicated one. If the former is the Rx  powered via the Esc or  independent if  independent have you disconnected the Red wire ln the Rx connection.
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frogman3

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Re: HELP FAILSAFE FOR A 2.4 GIG R/C
« Reply #37 on: August 26, 2020, 08:13:27 PM »

Are you are talking about the  failsafe in the Esc  or a dedicated one. If the former is the Rx  powered via the Esc or  independent if  independent have you disconnected the Red wire ln the Rx connection.


HI Jaymac  well if i understand you correctly the R/X is suppoce to have a F/S in built  on cha 3 an just lookin through my ESC instructions an it says if signal is lost motor stops so thats a failsafe isnt it ? an this ESC IS RATED AT 30 AMPS  but soeone eles told me to take out the red wire an i did an the ESC wont work until i reconned it AN THE ESC HAS NO BEC  so do i take out the red wire ?


cheers for your help
chris
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tsenecal

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Re: HELP FAILSAFE FOR A 2.4 GIG R/C
« Reply #38 on: August 26, 2020, 09:16:07 PM »

According to page 13 of the owners manual:

"The throttle position when turning on a receiver power supply will be fail-safe position.  The throttle moves to this low position in an emergency."

The illustration shows the throttle in the low position (idle for an airplane), but that just means if your boat has forward and reverse, you want the throttle centered when you turn the receiver on.

please note, the common practice is to turn on the transmitter first, then the receiver.  I have no idea what the F/S setting for the receiver would be if you turn on the receiver first, then the transmitter.
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JimG

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Re: HELP FAILSAFE FOR A 2.4 GIG R/C
« Reply #39 on: August 26, 2020, 09:26:52 PM »


HI Jaymac  well if i understand you correctly the R/X is suppoce to have a F/S in built  on cha 3 an just lookin through my ESC instructions an it says if signal is lost motor stops so thats a failsafe isnt it ? an this ESC IS RATED AT 30 AMPS  but soeone eles told me to take out the red wire an i did an the ESC wont work until i reconned it AN THE ESC HAS NO BEC  so do i take out the red wire ?


cheers for your help
chris
If the ESC doesn't have a BEC then you must keep the red wire to the receiver connected. This is providing the power to the ESC to control the output.
Jim
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frogman3

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Re: HELP FAILSAFE FOR A 2.4 GIG R/C
« Reply #40 on: August 26, 2020, 09:44:11 PM »

If the ESC doesn't have a BEC then you must keep the red wire to the receiver connected. This is providing the power to the ESC to control the output.
Jim


HI Jim many thanks for the info  an will leave the red wire in
chris
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jaymac

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Re: HELP FAILSAFE FOR A 2.4 GIG R/C
« Reply #41 on: August 26, 2020, 11:27:39 PM »

Hi Chris yes as Jim Says  leave Red in I only said  Remove if you were  feeding the Rx independently as opposed to from the Esc
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frogman3

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Re: HELP FAILSAFE FOR A 2.4 GIG R/C
« Reply #42 on: August 27, 2020, 10:21:01 AM »

Hi Chris yes as Jim Says  leave Red in I only said  Remove if you were  feeding the Rx independently as opposed to from the Esc


HI Jaymac yes im gonna leave in the red wire an hope that when this add on failsafe devise arrives i'll try it an see what happens as this problem is sendin me round the bend as i darein try an sail norfolk now in case she turns rouge an causes damage to others an herself but thanks to all for tryin to help me
chris
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Captain Flack

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Re: HELP FAILSAFE FOR A 2.4 GIG R/C
« Reply #43 on: August 27, 2020, 11:52:33 AM »

Are we not confusing the issue with BECs and red wire disconnection?  I thought the original question was about a fail safe, probably through the TX/RX combination.Can we keep it simple and not get too technical.Thanks
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chas

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Re: HELP FAILSAFE FOR A 2.4 GIG R/C
« Reply #44 on: August 27, 2020, 12:40:33 PM »

I've read through this thread twice now, and I've found it quite confusing. All my models behave the same way, if the signal is lost, either through a flat battery, or switching the transmitter off the same thing happens. I.e. it just stops, and that's fail safe enough for me.
  I use futuba, Fleet, spectrum and hobbyking , 2.4 gig and 40 MHz radios. Speed controllers are viper and hobbyking. Brushed and brushless motors.
   Maybe I'm just lucky, but I've always assumed that this is the norm.
Chas


   
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frogman3

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Re: HELP FAILSAFE FOR A 2.4 GIG R/C
« Reply #45 on: August 27, 2020, 01:23:01 PM »

Are we not confusing the issue with BECs and red wire disconnection?  I thought the original question was about a fail safe, probably through the TX/RX combination.Can we keep it simple and not get too technical.Thanks


YES i totaly aggree an yes it was about failsafe at the start as thats my problem
chris
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frogman3

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Re: HELP FAILSAFE FOR A 2.4 GIG R/C
« Reply #46 on: August 27, 2020, 01:28:29 PM »

I've read through this thread twice now, and I've found it quite confusing. All my models behave the same way, if the signal is lost, either through a flat battery, or switching the transmitter off the same thing happens. I.e. it just stops, and that's fail safe enough for me.
  I use futuba, Fleet, spectrum and hobbyking , 2.4 gig and 40 MHz radios. Speed controllers are viper and hobbyking. Brushed and brushless motors.
   Maybe I'm just lucky, but I've always assumed that this is the norm.
Chas


HI Chas you are lucky in my opinon but my model is fairly complex with severall workin features but if you get on ok with your R/C  great enjoy your sailin times
chris




 
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chas

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Re: HELP FAILSAFE FOR A 2.4 GIG R/C
« Reply #47 on: August 27, 2020, 03:51:26 PM »

Hi Frogman, sorry if I wasn't very clear, I'm also sorry if you read some sort of criticism into my question. Some of my models have plenty of working features too,  including motor mixing, some are also quite quick and I'd hate it if they went off on their own.
    I was trying to say that regardless of the radio used, they all just stop if the signal is lost. Are there some speed controllers that don't do that? Even my very first esc, a home build from a kit 30 + years ago stopped on signal loss, hence my confusion with the issue.
 I'm obviously missing something here, I'd just like to understand better.
Chas

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frogman3

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Re: HELP FAILSAFE FOR A 2.4 GIG R/C
« Reply #48 on: August 27, 2020, 06:17:04 PM »

Hi Frogman, sorry if I wasn't very clear, I'm also sorry if you read some sort of criticism into my question. Some of my models have plenty of working features too,  including motor mixing, some are also quite quick and I'd hate it if they went off on their own.
    I was trying to say that regardless of the radio used, they all just stop if the signal is lost. Are there some speed controllers that don't do that? Even my very first esc, a home build from a kit 30 + years ago stopped on signal loss, hence my confusion with the issue.
 I'm obviously missing something here, I'd just like to understand better.
(Chas Qoute)


HI Chas well for you to understand better i'll exsplain whats happening i have a big 6ft model of a type 23 frigate hms norfolk in 1/72 scale an its been sailin ok but its stood for a yr since the last sailin due to corvid an well i took her up my pond where i sail an an she was sailin great for about 10 to 15 mins then all of a sudden she just went rouge.


 An shot across the pond flat out an that's faster than i can run but thankfully some holliday makers see her comin towards them an one of the blokes put his hands  out to stop her hittin the concrete wall of our pond an saved her an i thought id got a fuse blew so i thanked them an towed her back to where our table is an i checked her over an all fuses all A-OK.


 So we lifted her back into the water an within say 10 mins or so it did it again an again thankfully the missus can run faster than me as she saved it hittin the wall again so i packed up an home with it an now when it loses signal the motors cut out a couple of time on test as my R/C is suppose to have a failsafe in built but its not workin properely  as when i switched off the T/X the green light on the R/X went to red sayin sinal loss.


but it dint stop the motors they were goin flat out so its a danger to itself an others as i dont want to clobber another model SO do you understand now Chas ? i only hope i can cure the problem as ive just been to my local R/C model shop an he got me a add on failsafe unit to fit between the R/X an the motors an im now goin to try it but im not confident it will work as ive herd so much that i now dont know what to belive  OH DEAR
chris

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DaveM

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Re: HELP FAILSAFE FOR A 2.4 GIG R/C
« Reply #49 on: August 27, 2020, 07:05:37 PM »

I've prepared a note which might help explain failsafe. I've tried to attach it as a txt file but the results were unusable, so if you'd like a copy then please PM me with your E-Mail address and I can forward it as a doc file.
Dave M
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