OneShot125+BLHeli+Damped Light

Hi all

I’m so sorry I wasn’t filming this morning :joy:

Today I was testing 3.4RC1 on a QAV-400 style quad that has self tightening propellers

My ESC’s were flashed with BLHeli, and I’ve enabled OneShot125 and Damped Light on the ESC’s.

So, I was flying several Flight Modes without issues, and then I decided to test the safety features like Motor Interlock and Emergency Stop.

So while hovering at about 4/5 meters from the ground I engaged Emergency Stop, but wasn’t expecting that the 4 props untightened themselves simultaneously and flew away, because the motors braked instantly :smiling_imp:

So, to all that use self tightening props, watch out for Damped Light on the ESC’s. It gives great response, but you might end up doing the search of shame for props on the field…

Ah yes, been there! PTFE or thread lock is a good idea with self tightening props, and make sure they’re well hand tightened. I had completely forgotten about this when I built a mini quad recently with t-motor air 2000 propulsion set that uses 9" self tightening props and hobbywing ESCs with active braking, haven’t had any problems with them flying off so they must have solved that problem somehow.

Yes, Had all the “usual” precautions, like thread lock and really tight by hand, but the emergency stop with Dampening Light enabled was so violent that nothing could resist that.

On all the other “normal” flying conditions no problem…

Wasn’t the Inspire that also had issues initially with self tightening props ?

Luis , how did you get the escs to run OneShot125?

I have several escs , mostly afro and HK blue series but none of them worked when I switched ardupilot to mot_pwm_type 2. Only type 1 is working. What I did was to change the parameter to 2 , rebooted everything and tried to do the calibration routine. However the escs didn’t entered in calibration mode with full throttle like it should be. With type 1 everything went well.

Olá Fernando

It was a saga at the beginning

I had to flash these

and these

with BLHeli 14.6

I’ve configured all of them like this:

On 3.4 I’m using the new parameters for motor PWM Max and Min and set them to 2000/1000, so the output to the ESC is independent of the Throttle. Also

I had to test all the combinations of Calibration so calibrated every combination of MOT_PWM_TYPE with Radio calibration and manually setting values on the BLHeli interface, and all combinations of radio calibration worked great, manually setting values not so great because each ESC has slightly different clocks and interprets 1000us in a slightly different way…

I tested everything with a Logic Analyser connected, so I’m pretty sure of the results.

One note. I did not use the MP ESC calibration interface. I just set ESC_CALIBRATION parameter to 1 and reboot the PixHawk with the radio throttle high, and from there just follow the usual procedure of ESC calibration with BLHELI.

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Olá Luis,

Thanks for the explanation. I’m not using the new pwm min max values, however i’m not sure if they play a role on activating oneshot125.
It didn’t work with type 2. All three escs initializes but nothing happens after. Since they are running fine with mot_pwm_type 1 I believe it could be something with those escs. Could you please check if your escs runs fine wherever you change between type 1 and 2 without doing anything else ( like calibrating etc )?

Anyway, I’ll take a look on the source code to see if there’s something missing from my parameters…

Btw, the escs that I’m currently testing are :

Run fine, but have to cut power and let the ESC’s reboot again.

What you describe looks like that the min PWM that gets to the ESC’s is not enough to arm the ESC’s.

Please note I’m using BLHeli firmware and boot loader on the ESC’s, not SimonK

Thanks Luis,
I’m running blheli 14.6 as well, however i haven’t updated the booltoader. It could be the issue. Probably HK shipped those escs with simonk bootloader. I’ll try to update them tomorrow with usbasp and let you know.

Since it will be necessary to disassemble almost all my tricompter to test, I’ll first post the question on rcforums just in case…

Are you shure that your esc can run oneshot?

Yes Cala. You are absolutely right. Not all ESC can run OneShot and/or Oneshot125.

Damped light: It’s looks nice for racer and acrobatic quads, but Im not shure if like to big ones, if something fails, props help to land autorotating but what happend if the esc stop motors when you don’t like to do it? opinions?

No, I’m not sure. On HK description it states that yes, they should, but i don’t know if the information is reliable.

What I wanna be sure before disassembling the tri is if blheli bootloader is mandatory for oneshot125. I couldn’t find this information anywhere.

I slightly disagree with you. From my brief experience with OneShot and Copter on smaller and larger copters (quad and hexa), the positioning of the copter is way more precise and it becomes easier to control, but that’s a personal preference :slight_smile:

Luis, mine is more a question than an answer, I don’t have experience yet with this tools, I’m assembling my first racer to have it, your experience is much apreciate, thank’s.

This has been my experience. I have ZTW ESC’s with BlHeli on my 450 quad with settings for braking and Oneshot (same as yours) and mot_pwm_type set to 2 and it’s very responsive. I use a Naze32 FC strictly for ESC programming :slight_smile:

Reporting back , yesterday I installed blheli bootloader in one of my afro 12a esc and it still doesn’t recognize OneShot125. So, it isn’t a bootloader issue. I suspect that the esc is not capable of dealing with OneShot125 frequency despite HK description.

I’ve posted a question in blheli rcgroups thread, no one has given a clarifying answer. They don’t seem to understand the Oneshot vs OneShot125 difference in Ardupilot config and i couldn’t explain.

For now I’m satisfied with the results of mot_pwm_type 1 , however i’ll keep this in my radar.

Thanks for your attention!

Luis, the manual method looks to work, thank’s; tomorrow first flight I hope.

Glad it helps. Sometimes easier things are just that. Easier…

Fly safe :slight_smile:

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Hi all, did anybogy find how to set the ESCs to OneShot125? I have DYS40A and copter flies with PH1 putting out OS125 values but it takes forver for the ESCs to arm/realize that they are getting Os125 signals. Also the BLHELI suite sais ESC expects 1000-2000 but it only gets 125-250.