3.5" Freestyle First Self-Build Advice

There is no min throttle for dshot, I think it’s cli idle_percent or something.

Let me have a quick search.

And yes you really want airmode on (maybe switch if you want to disable it for perching, etc)…

Quick google, get digital_idle_percent I think, maybe reduce that a little?

Lol.ots right there in the screenshot at 5.5. try dropping that

Like I said, the idol throttle is producing enough thrust to lift the quad off the ground slightly, this then triggers the air mode bounce effect.

Might be worth counting the magnets on your motor bell as well and making sure the correct number is input into betaflight. Just an idea.

It’s in the PID Tuning tab under Throttle and Motor Settings on the right hand side. I’d guess 0 is off and a value between 3000 and 3500 is on.


If it’s off (set to 0)

then I’d try reducing the 5.5 Motor idle down a touch and make sure Air mode is on and try again see if still bounces :+1:t2:

Thanks. I had about 5 minutes to play around with the dynamic idle, which seemed to improve things (it disables the motor idle % setting) but the motors sounded very sketchy!

I’ll play around with the Motor Idle % and the Dynamic Idle when I have more time. From some research, using the latter has more benefits.

Is it worth increasing the capacitance of my low ESR capacitor from the current 470 micro farads? From the very short tinkering today, I’m wondering if too much noise is getting into the system.

Hi, for a 3.5” quad a 470uF capacitor is fine :grinning:

Hey everyone,

Back again with another update on my quad build saga. Unfortunately, it seems like I’m hitting a wall, and I’m trying to resist throwing in the towel, so I could really use some more help.

No matter what I try, whether airmode is on/off, adjusting motor idle percent down to as low as 1.5%, the quad is determined to fly off the moment I arm it with zero throttle. Occasionally, I’ll arm and it’ll seem fine, then once I blip the throttle it takes off and I can’t land it without disarming.

Despite the countless tutorials and hours of troubleshooting, the issue persists. I’ve re-soldered every connection on the AIO twice, swapped out the capacitor, and replaced a motor that seemed off. But, no luck.

I’ve also removed the buzzer and cables for the buzzer and DJI O3 to rule out any potential interference – to no avail.

At this point, I’m wondering if the issue might be the AIO or gyro itself. Does anyone have suggestions for additional checks I can perform to confirm this suspicion?

The frame is an AOS 3.5 V5, which I would expect to fly fine with the default Betaflight tune.

Any insights or advice would be greatly appreciated! Cheers.

have you adjusted your board orientation? I’ve just noticed that your forward arrow is pointing off at 45 degree angle because its a woop/toothpic board?

Yeah, I have and confirmed in Betaflight Configurator that the quad rolls/pitches/yaws in the correct direction.

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I have a blackbox log from the short outdoor flight if that’s useful for anyone? I’m trying to get my head around it.

A suggestion as I remember Botgrinder having a similar problem .

See video and comments - Turning the PIDs ?

Vibrations ?

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I think JB’s streaming in about half an hour. You could probably do worse than super-chat him a couple of quid and email a link to that video. If nothing else it’ll inspire him to do drone noise impressions!

The motors sound very unusual - my first thought would be excessive vibration or not enough filtering. But I also agree that an AOS frame shouldn’t suffer from that out of the box, and I feel pretty sure you’ve probably defaulted the filters in the course of your trouble-shooting.

Are you running RPM filtering? If so is the number of poles set correctly?

I’m sure you’ve probably checked the integrity of your build about a million times by now, but maybe worth checking for manufacturing defects in the carbon - a hairline fracture in an arm maybe, that kinda thing.

This was my suspicion for a while, which is partly why I removed the buzzer and O3 wiring - to reduce the chances of any wires passing vibration to the FC as they were previously passing over the top of the board. It didn’t change anything though.

I’ve kept everything else clear of the FC, which is mounted on gummies. I’ve messed around with the PIDs and filtering, both messing with the master slider and trying a couple of presets. In some cases, it stopped the quad immediately taking off but once it was an inch off the ground it was almost uncontrollable.

Yep and and yep - set to 12 poles for the 1404 motors.

Yeah. Bi-directional DSHOT is on and my BLHELI_32 is up to date as well.

I have in its assembled state but I’ll disassemble the frame over the next couple of days to have a better look.