Frequently asked questions
What PIDoctor does, what it needs, and how to use its recommendations — in short.
What is PIDoctor?
PIDoctor is a free web tool that automatically analyzes your Betaflight blackbox log. You upload the log, describe your build, and get a deep tuning diagnosis — FFT spectra, step response, filter effectiveness and a tune score — plus ready-to-paste CLI commands for both PIDs and filters.
Is PIDoctor free?
Yes, you can start for free. After a quick sign-in your first 3 analyses are free — with no code needed. For more, there is an access code, or you can support the project with a voluntary donation. The live demo runs with no sign-in at all.
Does PIDoctor analyze filters, not just PIDs?
Yes — filters and noise are a core strength. PIDoctor shows FFT spectra of the gyro (filtered and unfiltered) and the D-term with the filter cutoffs overlaid, so you can see whether your filters cut where the noise actually sits. It detects motor noise, D-term noise and poor filter effectiveness, and outputs concrete CLI commands for gyro/D-term lowpass, dynamic notch and the RPM filter. Because the tune score separates noise/filters from the PID metrics, you can tell straight away whether your problem is the filters or the PIDs.
Which log files are supported?
Betaflight blackbox logs (.bbl / .bfl), recorded from onboard flash or a blackbox module. For the deepest filter analysis the log should include the unfiltered gyro (via the debug mode).
How do I log for the best analysis?
In the Betaflight blackbox tab, set a sufficient sample rate and pick a debug mode that also records the unfiltered gyro (ideally the D-term values too). Then fly a few deliberate stick inputs per axis. If data for the full filter analysis is missing, PIDoctor tells you honestly instead of guessing.
Do I need an account?
For the live demo, nothing. To analyze your own log you sign in once (e.g. with Google) — then you get 3 free analyses. The account also stores your flights and builds for later.
What happens to my log files?
Your log is transferred to the server and processed for the analysis. The result page is set to noindex, so it is not publicly discoverable in search engines. Exactly what is stored is described in the privacy policy.
What is the tune score?
The tune score is an overall rating from 0–100 with a grade, made up of several sub-scores: tracking and step response (PIDs) as well as noise and filter effectiveness. That lets you see at a glance where your tune stands and which dimension is the actual problem.
Which Betaflight versions does it work with?
PIDoctor reads logs from Betaflight 4.x and adapts the suggested CLI commands to the detected firmware version, so the commands match your version.
Can I apply the CLI commands directly — is it safe?
The commands are suggestions, not instructions — review them before applying. On a computer you can connect your flight controller over Web Serial and send the commands directly; always take the propellers off first. The decision and responsibility rests with you (see the terms of use).
Why are my motors hot after flying?
Hot motors almost always come from noise the filters don't remove — not from high PIDs alone. Unfiltered motor or D-term noise reaches the motors and heats them up. PIDoctor shows in the FFT where the noise sits, checks whether your dynamic notch and RPM filter actually attenuate it, and suggests filter CLI commands that tackle the heat at the source.
Is my problem the PIDs or the filters?
That's the first question PIDoctor answers. The tune score separates tracking/step response (PIDs) from noise/filter effectiveness, so you can see immediately which dimension is holding you back. Many supposed PID problems — hot motors, ringing — are actually filter problems, and PIDoctor tells you which of the two it is.
Does PIDoctor auto-tune my quad?
No — and that's on purpose. PIDoctor is an honest diagnosis, not a magic auto-tuner. It objectively measures what your log shows, explains the findings and suggests concrete CLI commands. You apply and decide — so you stay in control and learn in the process, instead of trusting a black box.
Do I need to understand PID tuning to use PIDoctor?
No. You get a clear diagnosis in plain language plus ready-to-paste CLI commands. If you want to understand more deeply, every finding links the relevant guides and glossary terms — so you can just use the suggestions or learn step by step why they help.
How do I fix propwash?
Propwash — the low-frequency oscillation on descents and hard turns — usually comes from a mix of too much filter delay, D-term tuning and feedforward. PIDoctor detects propwash from the step response and spectrum and shows which of these causes dominates for you. The fix-propwash guide walks you through the correction step by step.
Why does my quad oscillate or wobble?
Oscillations have different signatures: high-frequency buzz usually points to noise/filters, low-frequency wobble often to too-high P gains or propwash, mid-throttle oscillation to motor resonance. PIDoctor reads the frequency and axis from the log and maps your wobble to its likely cause.
What is a good tune score?
Roughly: 80+ (grade A/B) is a solid, well-flyable tune; 60–80 has clear room to improve; below 60 usually means a concrete problem like poor filters or heavy overshoot. More important than the number are the sub-scores — they show whether tracking or noise/filters are dragging you down.
Do I need bidirectional DShot and the RPM filter?
For most builds yes — the RPM filter (which requires bidirectional DShot) is the most effective way to remove motor noise at the source and therefore run less lowpass delay. PIDoctor checks whether your RPM filter is active and effective, and flags it when the motor harmonics still get through.
Can I analyze if my log has no unfiltered gyro (debug mode)?
Yes, partly. Tracking, step response and the PID side of the tune score work even without the unfiltered gyro. The deep filter analysis (filtered vs. unfiltered) needs the right debug mode, though — if it's missing, PIDoctor says so honestly instead of guessing, and you re-log with debug mode on your next flight.
Does PIDoctor work for tinywhoops, 5-inch, 7-inch and cinelifters?
Yes. Because the analysis is based on the blackbox log and the build you describe, it works for any quad size from tinywhoop to cinelifter — as long as it's a Betaflight log. The build details help PIDoctor put the findings in the right context.
Does it work with DJI, HDZero or Walksnail?
Yes — the video system doesn't matter. PIDoctor analyzes the Betaflight blackbox log from the flight controller, not the video. Whether you fly DJI, HDZero, Walksnail or analog: as long as your FC records a Betaflight log, you can analyze it.
Can I use PIDoctor on my phone?
Uploading and viewing the analysis works on a phone too. Sending the CLI commands directly to the flight controller uses Web Serial and needs a desktop browser (Chrome/Edge) with a USB cable — but you can view the commands anywhere and apply them at a computer later.
How often should I re-tune?
Whenever something relevant changes on the setup: new props, motors, frame, different weight or a firmware update. Otherwise it's enough to pull a short log after hardware changes or when you notice problems (hot motors, wobble, propwash) and upload it.
How long does my log need to be?
One to two minutes of active flying with a few deliberate stick inputs per axis is enough. More important than length is content: clear roll/pitch/yaw moves for the step response and some full throttle for the noise analysis. Pure hovering gives too little signal.