How it works
One device, not a rig
A GPS-enabled GoPro or DJI films and logs in a single box. No phone mount, no pairing, no cables.
Upload when you get in
Browser or Windows uploader. Processing runs in the cloud while you get on with your day.
Read the session properly
Laps and sectors timed, racing lines drawn, coaching notes pointed at the exact moments on film.
What changes when video is the source
A logging rate that holds up
A phone fixes its position once a second. A GoPro does it ten times. At speed that's the difference between a 50-metre blind spot and a five-metre one, and it decides how much you can trust the times.
Kit built to be out there
No phone strapped to a vibrating race car. An action camera is made for heat, knocks and rain, so you're not gambling an expensive handset on a clean session.
Every number has footage behind it
Click any sector time and watch the seconds of video that produced it. The data and the evidence are the same file.
Coaching included
Loggers hand you charts and leave the interpretation to you. Race Ninja writes the debrief: which corners cost time and what to do about them.
Common questions from Harry's LapTimer users
Is there an alternative to Harry's LapTimer?
Race Ninja, coming at it from a different angle. Harry's LapTimer turns your phone into a data logger and does it well. Race Ninja turns the camera you already film with into the whole system: lap timing, sector analysis, racing lines and coaching, processed from the footage after your session.
How much does a phone GPS limit the timing?
More than most people realise. An iPhone's built-in GPS updates about once a second. A car at 180 km/h covers 50 metres in that second, so the phone only knows your position in 50-metre jumps and has to guess everything in between. A GoPro logs ten times a second, so those jumps shrink to about five metres. Lap and sector precision comes straight off that sampling rate, and a phone samples too rarely for it.
What about pairing a 10Hz or 25Hz external GPS receiver?
Plenty of Harry's users run one, and it does close the phone's sampling gap. But chase the numbers and you hit diminishing returns fast. The move from one fix a second to ten is transformative: at 180 km/h your blind spot between fixes drops from 50 metres to five. A 25Hz puck only takes that from five metres to two, and a consumer GPS fix is already uncertain by a metre or two on its own, so those extra samples fall inside the error rather than sharpening the picture. You've bought a second box to charge and pair, your phone is still on the car, and a GoPro already logs at the 10Hz that captures the gain, with the video locked to it.
Do I want my phone mounted on a race car or kart?
It's worth thinking about before you rig it. Vibration, heat and the odd off are hard on a phone, and a cracked or dead £1000 handset is a costly lap timer. Action cameras are made to be bolted on and battered. Your phone isn't.
Do I lose live timing?
On-track live timing, yes. Race Ninja processes footage after the session rather than showing times as you drive. If glancing at live deltas mid-lap matters to you, a phone app still does that; most drivers we work with read the session in the paddock afterwards anyway.
Does it work for cars and track days, or just karts?
Both. Karting is where most of our drivers race, but the analysis works the same for car track days: laps, sectors, lines and coaching from the same onboard footage.