GPS-based race timing engineered for competitive open road racing. Centisecond ahead/behind display, automatic GPS waypoint detection, and thousandths-of-a-mile mileage tracking — built and supported directly by the developer.
Silkrip Motorsports builds GPS-based race timing systems for competitive open road racing. Every Mark V is personally designed, assembled, calibrated, and supported — because the developer races these courses too.
The Mark V is the result of years of refinement on real courses in Nevada and Texas. It delivers centisecond timing accuracy with GPS PPS synchronization, automatic waypoint detection, and comprehensive data logging — everything you need to compete at the highest level of ORR.
Based in San Francisco, CA. When you reach out, you talk to Tom King — the engineer who built your computer.
The Mark V handles the timing so you can focus on the drive. Simple race sequence: set course, set speed, arm at the start — the rest is automatic.
Primary race mode shows real-time Ahead/Behind time to 0.01 seconds. GPS PPS-synchronized start at the exact :00 or :30 second mark — no guessing.
Waypoints detected by GPS coordinates — no manual triggers. Mileage auto-corrects to official course mileage at each station. Green LED approaching, red LED passed.
MILES mode shows accumulated mileage to 0.001 mile. Auto-corrected at every waypoint so you always know exactly where you are on the course.
Single high-brightness 8-digit LED display. Mode selected via an illuminated rotary switch: RUN, MPH, TGT, SW, ANT, CRS, LOG, MILES. Day or night legibility.
Leg 1 error automatically saved and applied to Leg 2. Use RESET between legs to preserve GPS lock — no satellite reacquisition delay at the Leg 2 start.
Full race simulator for bench testing — no driving required. LOG mode lets you create custom practice courses by driving any route and logging 10 GPS waypoints.
Special ER courses pre-loaded for SSCC/NORC red-flag situations: Flag 3 Southbound, Flag 6 Southbound, and Flag 6 Northbound. Race official–directed restarts covered.
Every race logged to microSD (32GB max, FAT32). Leg results, timing marks, GPS data — all saved automatically. Works without a card too; no card = no logs but full operation.
Arduino MKR Zero (ARM Cortex M0+), Adafruit 10Hz GPS, MAX7219 LED driver. 12V automotive power with regulation. Field-tested across Nevada and Texas courses.
Eight positions on the illuminated rotary switch give you full control of what the Mark V shows and does.
| Position | Display | Function |
|---|---|---|
| RUN | A/B time | Primary race mode — shows Ahead/Behind time in centiseconds |
| MPH | Speed | Current GPS speed in MPH |
| TGT | Target speed | Set/view target speed (50–180 MPH, press to increment by 5) |
| SW | Elapsed time | Raw stopwatch — total elapsed race time |
| ANT | Antenna dist. | GPS antenna distance from front bumper (3–8 ft, press to increment) |
| CRS | Course select | Select race course C0–C9; long press (4 sec) enables/disables Simulator |
| LOG | Log mode | Create custom practice courses — press to activate, log up to 10 waypoints |
| MILES | Mileage | Current accumulated race mileage to 0.001 mile |
Every Mark V ships with 10 pre-loaded course profiles including emergency restart variants. Plus a custom slot you can program with LOG mode.
Complete system plus optional accessories for bench testing and field use.
Every Mark V is personally built and supported. When you reach out, you're talking directly to Tom King — the engineer who designed and races with this system. No support queue. No middleman.