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Low Cost Video Telemetry Solution

GeorgeCo was at the track again mid-November for the NCC BMW CCA Fall HPDE at Summit Point Motorsports Park. GeorgeCo drove the MINI on Friday/Sunday and the Porsche Saturday in between. This was GeorgeCo’s first drive of the Porsche at the track. The car is larger and heaver than the MINI, but really accelerates well out of the corners, even on the not-so-grippy full-tread summer tires that came on the car. We still have some issues to sort out, but the car is progressing nicely. More on that later. First the MINI.

We’ve been working on a (relatively) low-cost video telemetry system and have finally worked most of the bugs out of our set-up. The video above uses an iPhone 4, Optrix-HD iPhone Mount, Harry’s LapTimer software, External GPS sensor, and a PLX-Devices data-interface. The iPhone is used for video capture and accelerometer function. It captures OBD-II data from the PLX-Devices Kiwi WiFi and combines it with 1 meter accurate GPS data from the external GPS device via Bluetooth. Ho, ho-ho, ho…. The iPhone does the post-processing and overlays all of the data on the video. In this video, I’m tracking down my friend John who is in the red E30 which is prepared very similarly to the old GeorgeCo E30. I like this video because you can see the driver’s hands, whether he’s looking ahead into the corners, and the telemetry shows revs as well as how much of the lap is spent on full throttle (less so in traffic.) I need to work on getting a brake sensor.

The second video was filmed in the Porsche 996 Carrera using a ReplayXD camera mounted on the sunvisor. This is an example of how you can combine video from external sources. The initial video was exported to an iMac and then uploaded to the iPhone via iTunes. It was then imported to LaptimerPro for overlay with Laptimer data. We didn’t have the OBD-II data connection working on this day, so the only data sources were the accelerometer and external GPS. The key to this process is to find the key video frame at the end of the timed lap so LaptimerPro can match the data-stream correctly. In this video, the Porsche is on Summer Street Tires which have no grip on the cooling track.

This third video shows the value of video as a learning aid. I followed my friend (and newly minted instructor) Dave for a few laps. He eventually went off in turn 1 when his tires gave out, got a nice mud bath, then almost went into a tank-slapper when he came back on. Fortunately he got his act together and we had some distance between us. The final shows what it must have felt like from his point of view…