What do you do when your transmitter loses connection but the car keeps going?

[triplebeastalpha]

My buddy had this issue a few months back, and it just happened to me. On both occasions the cars were not going particularly fast thankfully but it has made me worry somewhat that it's going to happen when I'm gunning it and there's going to be a serious accident.

For context, my friend has a Traxxas Maxx and his TQI transmitter ran out of battery mid drive, mid skate park, with some (thankfully not loads) of people around. he was fortunate that the car had just entered low voltage mode so it was going at a leisurely pace and there were no accidents. It's an honest mistake but one which can be avoided so I didn't worry too much about it happening to me.

Fast forward to last weekend, I had just fixed my Kraton and, having bought a DX5c transmitter was desperate to test it out. I put in an old Spektrum receiver I had lying around and got everything set up the night before. I go out to the local skatepark in the morning. The park was sparsely populated but unfortunately there were a couple of mums on the skatepark with their toddlers. The skatepark is fenced off so figured I'd give it a little go in the field whilst I waited. everything seemed to work fine at home but now the transmitter was not connecting to the car. after a little messing, turning it off and on, it connected but was very patchy. It was stop-start for a few seconds then nothing. As I started walking over to it (probably still pulling and twisting things trying to get a connection) it just takes off, again, thankfully not too fast as I'd turned the punch right down whilst testing it all, but it was fast enough that I couldn't catch it. Of all the safe directions to go in it instead heads straight for the open gate to the skatepark and proceeds straight into one of the unsuspecting mums. In one sense it was ridiculously unlucky but in another it also could have been a lot worse. I obviously took a good lot of flack but no one was hurt.

This has got me pretty shaken up, I've got some pretty big, heavy and powerful cars and I never really thought about what would happen if one of them went ghost on me. How can I avoid this in future? Maybe I should have tested the receiver/car more before taking it out? Maybe run it at half power first to make sure everything is okay? It's a max6 esc in an arrma kraton 6s, I've bought a hobbywing program card now to see if there are any safety settings, it seems mad to me that when the transmitter loses connection it seems to just carry on with whatever the last input was. Why doesn't it automatically shut off when it has no input?

Any help or advice would be greatly appreciated

 

[HZRDOS]

Run really fast?

 

[Robbbbbb66]

My buddy had this issue a few months back, and it just happened to me. On both occasions the cars were not going particularly fast thankfully but it has made me worry somewhat that it's going to happen when I'm gunning it and there's going to be a serious accident.

For context, my friend has a Traxxas Maxx and his TQI transmitter ran out of battery mid drive, mid skate park, with some (thankfully not loads) of people around. he was fortunate that the car had just entered low voltage mode so it was going at a leisurely pace and there were no accidents. It's an honest mistake but one which can be avoided so I didn't worry too much about it happening to me.

Fast forward to last weekend, I had just fixed my Kraton and, having bought a DX5c transmitter was desperate to test it out. I put in an old Spektrum receiver I had lying around and got everything set up the night before. I go out to the local skatepark in the morning. The park was sparsely populated but unfortunately there were a couple of mums on the skatepark with their toddlers. The skatepark is fenced off so figured I'd give it a little go in the field whilst I waited. everything seemed to work fine at home but now the transmitter was not connecting to the car. after a little messing, turning it off and on, it connected but was very patchy. It was stop-start for a few seconds then nothing. As I started walking over to it (probably still pulling and twisting things trying to get a connection) it just takes off, again, thankfully not too fast as I'd turned the punch right down whilst testing it all, but it was fast enough that I couldn't catch it. Of all the safe directions to go in it instead heads straight for the open gate to the skatepark and proceeds straight into one of the unsuspecting mums. In one sense it was ridiculously unlucky but in another it also could have been a lot worse. I obviously took a good lot of flack but no one was hurt.

This has got me pretty shaken up, I've got some pretty big, heavy and powerful cars and I never really thought about what would happen if one of them went ghost on me. How can I avoid this in future? Maybe I should have tested the receiver/car more before taking it out? Maybe run it at half power first to make sure everything is okay? It's a max6 esc in an arrma kraton 6s, I've bought a hobbywing program card now to see if there are any safety settings, it seems mad to me that when the transmitter loses connection it seems to just carry on with whatever the last input was. Why doesn't it automatically shut off when it has no input?

Any help or advice would be greatly appreciated

Most of my radio Failsafe works except my Traxxas Xmaxx with a TQi radio that ran away into a trench filled with water...

 

[ZooKeeper]

I can't speak about your particular transmitter, but see if it has a failsafe setting and test it with the wheels off the ground.

I have the FlySky Noble NB4 and just recently went through this testing myself. The failsafe is fully configurable. I set it so the steering goes straight and the throttle to neutral in the event a connection is lost. On my Infraction specifically, I also set it to engage the handbrake if the connection is lost.

After setting up the failsafe, I put each car on a block so the wheels wouldn't touch the workbench, pulled the throttle to ~20% and turned off the transmitter. All my tests were successful - the wheels stopped spinning (and the Infraction handbrake engaged).

 

[triplebeastalpha]

I can't speak about your particular transmitter, but see if it has a failsafe setting and test it with the wheels off the ground.

I have the FlySky Noble NB4 and just recently went through this testing myself. The failsafe is fully configurable. I set it so the steering goes straight and the throttle to neutral in the event a connection is lost. On my Infraction specifically, I also set it to engage the handbrake if the connection is lost.

After setting up the failsafe, I put each car on a block so the wheels wouldn't touch the workbench, pulled the throttle to ~20% and turned off the transmitter. All my tests were successful - the wheels stopped spinning (and the Infraction handbrake engaged).

Thank you, I was obviously looking in the wrong place, I assumed it would have to be on the esc rather than the transmitter. I'm still confused as to how the transmitter can do this if the connection is lost but I'll look into it on the DX5c. It seems like a good transmitter so I'm sure it'll have something in there.

 

[ZooKeeper]

A lot of the fancier/high end radio systems have 2 way communication. That is - the "transmitter" and the "receiver" can both actually transmit and receive, allowing them both to constantly talk to each other. This is what allows you to receive telemetry data on your transmitter (car/receiver battery voltage, temp sensors, speed sensors, etc.).

When you configure the failsafe, that configuration is saved on the receiver installed in the car. (The following description may not be 100% accurate, but it should be fairly close...) The receiver and transmitter then play "ping pong" with each other. One will "ping", the other will reply with "pong" to know that it's still there. If the receiver in your car "pings" and the transmitter doesn't "pong" back, the receiver then knows the communications link is broken, and to then enter into the failsafe mode.

 

[Senton_Prime]

A lot of the fancier/high end radio systems have 2 way communication. That is - the "transmitter" and the "receiver" can both actually transmit and receive, allowing them both to constantly talk to each other. This is what allows you to receive telemetry data on your transmitter (car/receiver battery voltage, temp sensors, speed sensors, etc.).

When you configure the failsafe, that configuration is saved on the receiver installed in the car. (The following description may not be 100% accurate, but it should be fairly close...) The receiver and transmitter then play "ping pong" with each other. One will "ping", the other will reply with "pong" to know that it's still there. If the receiver in your car "pings" and the transmitter doesn't "pong" back, the receiver then knows the communications link is broken, and to then enter into the failsafe mode.

Yep
+1

 

[slick2500]

The failsafe is supposed to set automatically when you bind the receiver. So unless you were holding the throttle down while you were binding the receiver it did not go into failsafe mode. Something else is going on here.

Did you calibrate the end points for the esc?

Is the antenna wire still intact and free from damage?

 

[triplebeastalpha]

I’m starting to see this information everywhere now I know what to look for. Everything was set up fine as far as I’m aware. There were no noticeable problems when setting it all up, throttle range was set up on the esc, end points and trim on the transmitter were calibrated. I can’t see any damage to the antenna wire. I’m going to test that receiver further in my tiny 14th scale car so it can’t cause much damage but I can only assume it’s a faulty receiver.

I’ve installed a Spektrum SR315 receiver in the car now and it all seems to work well. Going to try the failsafe tonight and see if it functions correctly. It’s strange that it would happen to me and my friend within 6 months or so though, especially considering the price of the transmitters and receivers we were using and that both can handle onboard telemetry. The only thing I’m thinking now is that it may have something to do with the gyros. The TQI receiver has TSM and the Spektrum receiver I used had AVC, I think its the SRS4200.

 

[slick2500]

I’m starting to see this information everywhere now I know what to look for. Everything was set up fine as far as I’m aware. There were no noticeable problems when setting it all up, throttle range was set up on the esc, end points and trim on the transmitter were calibrated. I can’t see any damage to the antenna wire. I’m going to test that receiver further in my tiny 14th scale car so it can’t cause much damage but I can only assume it’s a faulty receiver.

I’ve installed a Spektrum SR315 receiver in the car now and it all seems to work well. Going to try the failsafe tonight and see if it functions correctly. It’s strange that it would happen to me and my friend within 6 months or so though, especially considering the price of the transmitters and receivers we were using and that both can handle onboard telemetry. The only thing I’m thinking now is that it may have something to do with the gyros. The TQI receiver has TSM and the Spektrum receiver I used had AVC, I think its the SRS4200.

Some strange radio interference?

 

[Moirae]

I had this happen a few days ago and it was scary af. I still haven't even looked at the rig but it turns on and zero steering or throttle. I hit a jump and the car landed and proceeded to take off on its own. Thankfully it ran into the annoying green box that's in the middle of my landing spot but wow it could have taken off across the field and into the streets.

I thought I had a fail-safe on but apparently I'm an idiot and had no idea what I was doing . This thread is helpful.

 

[LibertyMKiii]

• I have long-range radios setups
• Always fully charged before use.
• I run castle ESCs with the drag brake enabled at 30%. The car will slow down on its own and wait for me

 

[donnie533]

The failsafe is supposed to set automatically when you bind the receiver. So unless you were holding the throttle down while you were binding the receiver it did not go into failsafe mode. Something else is going on here.

Did you calibrate the end points for the esc?

Is the antenna wire still intact and free from damage?

Agree - something else seems to be going on here.
OP claims that the transmitter and receiver connection was flaky. This is a dangerous situation to run with.
I would check all receiver connections, and fresh batteries in the remote.
Re-bind receiver and transmitter, ensuring failsafe is set.

Perhaps the remote is faulty and did not properly communicate failsafe position to the receiver.
Since OP says he was "pulling and twisting things trying to get a connection" - I would lean to this being the problem.

I test failsafe and all functions on the bench - with the wheels removed (launched a 30 pound DBXL-E2 off the workbench once).

 

[triplebeastalpha]

I agree and if I ever get any issues with a connection again I’ll definitely just be turning it off. Better to be safe than sorry in this situation, even if I feel the failsafe should have kicked in I’ve no idea what signal it was receiving at that point so the first sign of fault I’ll always be turning everything off and testing at home from now on. Thankfully I have enough rigs that there’s always something else to drive. In all honesty I can’t remember what I was doing when I was walking over to it but I was probably pulling on the trigger wondering why it wasn’t doing anything. Rookie mistake I guess, I got lucky and hopefully learned a valuable lesson. I’ll be checking failsafe on all my rigs now and this one will stay in gated skate parks, early in the morning before anyone else arrives, until I can be certain it’s safe with that receiver and that the other one is faulty.

I had this happen a few days ago and it was scary af. I still haven't even looked at the rig but it turns on and zero steering or throttle. I hit a jump and the car landed and proceeded to take off on its own. Thankfully it ran into the annoying green box that's in the middle of my landing spot but wow it could have taken off across the field and into the streets.

I thought I had a fail-safe on but apparently I'm an idiot and had no idea what I was doing . This thread is helpful.

Just out of curiosity, what setup are you using?

 

[Moirae]

I agree and if I ever get any issues with a connection again I’ll definitely just be turning it off. Better to be safe than sorry in this situation, even if I feel the failsafe should have kicked in I’ve no idea what signal it was receiving at that point so the first sign of fault I’ll always be turning everything off and testing at home from now on. Thankfully I have enough rigs that there’s always something else to drive. In all honesty I can’t remember what I was doing when I was walking over to it but I was probably pulling on the trigger wondering why it wasn’t doing anything. Rookie mistake I guess, I got lucky and hopefully learned a valuable lesson. I’ll be checking failsafe on all my rigs now and this one will stay in gated skate parks, early in the morning before anyone else arrives, until I can be certain it’s safe with that receiver and that the other one is faulty.

Just out of curiosity, what setup are you using?

I'm using the radiolink

 

[carckton driver]

let me be the first to give a giant to anyone who gave you any crap about what was a honest accident that you already felt horrible about. does the idiot(s) who get mad about a runaway car honestly think you did it on purpose? i hope not, it which case it makes zero sense to get mad at you.

 

[Diem Turner]

I usually just watch it crash...not much else you can do by the time you realize you've lost connection.

 

[Senton_Prime]

let me be the first to give a giant to anyone who gave you any crap about what was a honest accident that you already felt horrible about. does the idiot(s) who get mad about a runaway car honestly think you did it on purpose? i hope not, it which case it makes zero sense to get mad at you.

Kinda makes sense if your talking about the "mum".. that was hit

 

[carckton driver]

Kinda makes sense if your talking about the "mum".. that was hit

the first words out of my mouth would have been "damn good thing it wasnt your TODDLER you brought to THE SKATE PARK." poop goes flying in skate parks, if your not prepared for that then stay away.

 

[triplebeastalpha]

I'm using the radiolink

Any gyro in the receiver?

let me be the first to give a giant to anyone who gave you any crap about what was a honest accident that you already felt horrible about. does the idiot(s) who get mad about a runaway car honestly think you did it on purpose? i hope not, it which case it makes zero sense to get mad at you.

Thanks, I appreciate you saying this, all I can do is move forward and try not to make the same mistake again

Kinda makes sense if your talking about the "mum".. that was hit

the first words out of my mouth would have been "damn good thing it wasnt your TODDLER your brought to THE SKATE PARK." poop goes flying in skate parks, if your not prepared for that then stay away.

It does kinda make sense from the 'mum's' perspective and I apologised profusely at the time but there's not a lot more I can do after that, except try not to make the same mistake again. I wouldn't have said it at the time but I do agree with what @carcktondriver is saying, especially considering all they were doing was sliding down the ramps, right next to an actual playground with slides that were completely empty. I'm not saying I'm absolved or anything but if you want your kid to be safe I've never understood the parents that do this, okay if it's empty when you arrive but I've had people enter with toddlers when I'm driving big cars fast and jumping high, they seem to expect me to take the precautions or leave. It just seems like an odd choice to me. Anyway, lesson learned, hopefully they realised the dangers of skateparks too, but probably not. I'll be going at 7am from now on to avoid these kinds of people