[HOW-TO] RaceCapture Device Configuration

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[HOW-TO] RaceCapture Device Configuration

Post by Harry »

As powerful as Autosport Labs' RaceCapture devices are, the many are the possible configurations...

When using one of ASL's devices with LapTimer, it needs to be configured in a way LapTimer is able to handle it. This article describes how to make a successful configuration and connection. Furthermore, it lists some low level definitions in case you want to tweak your system.

RaceCapture devices supported:
  • Bluetooth equipped RaceCapture/Pro MK1, MK2, MK3 and RaceCapture/Apex devices can be used with LapTimer's Android editions.
  • WiFi equipped RaceCapture, RaceCapture/Pro MK2 (with external WiFi), MK3 and RaceCapture/Apex can be used with both LapTimer's Android and iOS editions
LapTimer's latest edition expects RaceCapture firmware version 2.10.x


Configuration can be done using ASL's application available for macOS, Windows, and Linux, or using the RaceCapture Android app. LapTimer does not support direct RaceCapture device configuration currently. Instead, it expects a ready to run and properly configured system on the other side. We focus on a narrow set of parameters only. In case you want to do more sophisticated things, please check the list of channels supported below. Features like mobile connection, Podium, LUA etc are out of scope. They may work, but it is considered unsupported.

LapTimer uses GPS and Engine channels only currently. Support for IMU sensors (gyro and accelerometers) may be added later. Because of this, it is recommended to turn off IMUs in Setup ‣ Access/Gyro (all references in this section refer to ASL's apps). Turning them on, results in wasted BT / WiFi bandwidth.

Same applies to all features redundant to LapTimer's more advanced features: Race Tracks, Race Timing, Telemetry. Turn these items off when using a RaceCapture device with LapTimer.

Opposed to this, sections Analog Sensors, Pulse Sensors, Digital In/Out, CAN Bus, OBDII can be used to map inputs to channels supported by LapTimer.

Please do not use highest update rate only because it is possible in theory. Most users will never need more then 10 Hz, 25 Hz will always be good enough. For many channels an update every second is more than one needs. See the channel list for recommendations.

For the RCT, RCP MK2 with BT module, RCP MK3, RCP Apex, you can configure GPS and engine channels with any of the rates
  • 1, 5, 10, 25, 50 Hz
for the LapTimer v21 production version. For the RCP MK2 with Wifi module, one of
  • 1, 5, 10 Hz
must be used.

Wireless configuration depends on adapters included in your RaceCapture model and the smartphone platform used. For Android, Bluetooth will be preferable if available, while for iOS, WiFi is the only option.

Channels supported:

All channels which should receive a high update rate are shown at 25 Hz below. Please use 25 Hz for all RaceCapture devices expect the RCP/MK2 combined with a WiFi module. For this device, select 10 Hz instead.

Code: Select all

Group   Channel     Mandatory   Rate    Description and Unit
General Utc         yes          -      UTC time in milli seconds since 1970; coming in at highest rate selected
General Battery     no           1 Hz   Car system voltage

Engine  MAF         no          25 Hz   Mass Air FLow, in g/s; if not defined, MAP is mandatory
Engine  RPM         yes         25 Hz   Engine rounds per minute
Engine  WheelSpeed  no          25 Hz   Wheel speed in miles per hour; replaced by GPS speed if deselected
Engine  TPS         yes         25 Hz   Throttle position, in percent
Engine  MAP         no          25 Hz   Manifold Air Pressure, in kPa (absolute); if not defined, MAF is mandatory
Engine  FuelLevel   no           1 Hz   Tank fuel level in percent
Engine  EngineTemp  no           1 Hz   Engine (Coolant) Temperature in Fahrenheit
Engine  OilTemp     no           1 Hz   Oil Temperature in Fahrenheit
Engine  IAT         no           1 Hz   Intake Air Temperature in Fahrenheit
Engine  Brake       no          25 Hz   Brake pressure in PSI, supported for LapTimer v22 and later

GPS     Latitude    yes         25 Hz   Latitude of GPS position in degree
GPS     Longitude   yes         25 Hz   Longitude of GPS position in degree
GPS     Altitude    yes         25 Hz   Altitude in feet (can be negative)
GPS     Speed       yes         25 Hz   GPS speed, in miles per hour
GPS     GPSSats     yes         25 Hz   Number of satellites used for GPS lock
GPS     GPSQual     no          25 Hz   Differential status of GPS position delivered
GPS     GPSDOP      no          25 Hz   Dilution of Precision, factor used to derive accuracy
A word of caution. When updating your RaceCapture device to a new firmware version, it will often break compatibility. ASL has no working notification for 3rd parties when the interface changes in a not downward compatible way. So I learn about updates when the first users run into issues. The firmware version shown in the top is the one this article and current LapTimer versions has been tested against.

- Harry
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