Rae-San Electronics

Modern Electronics for Vintage Motorcycles


The OBD bridge measures important parameters on your motorcycle ( or other vehicle) and makes them available over a bluetooth connection to various "Dash" or OBD programs.

It does this by measuring the analog quantities, and some on/off lines, translating these into the values needed and then looking to the outside world like a normal ECU.

To the software it looks like an ELM327 (the most common OBD II interface) connected to a standard ECU.

This means that pratically any Dash software product is able to ask for the data, recieve and display the results. The testing is done using Torque Lite and Torque pro as this is available at low cost across many platforms.

The system can operate either in parallel with the existing dash units - measuring and sending the data to a "terrminal" for display or logging, or it can also be configured to provide the power to the sensors for operation where there is no existing dash and the bluetooth connected unit is used as the dash.

Quantities that are measured by default -

Fuel level(if available on bike), system voltage,coolant temperature, speed, tacho(engine RPM). with appropriate sensors additional measurements can be included - oil pressure, oil temp, throttle position and Air/Fuel Ratio.

Fuel level can be obtained fro a dedicated fuel sensor - or on fuel injected bikes it can be calculated fro the accumulated injector opening time - this gives a very accurate measure of the fuel consumption - and gives additional parameters that can be used - average fuel consumption and Distance to Empty. In this mode the Fuel Low input is used to connect to a switch / button that allows the once off calibration to be performed, and then to signal when the tank has been refilled.

On Off measurement is provided for high beam, over temperature, oil pressure low switch, Fan on, Fuel Low warning.

All inputs are configurable in polarity, and the analog inputs have adjustable ranges, and 2 point curve corrections to allow for the widest possible range of suitability.

A number of sensors will also be made available to support measurement of parameters that are not supported on the original configuration of the bike. Available now is a an oil pressure sensor that also maintains the correct signal to the low pressure oil light. In work is a Throttle Position sensor kit and a capacitive fuel sensor adaptor.

Configuration of the unit is performed via a USB connection and a simple ANSI terminal program (like Putty).

The OBD adapator can be used to perform a variety of functions - from a basic sending of the data to a display to replace the original dash, supplementing the original dash with a logging system or both.

Supports 4 profiles of settings allowing for easy transfer between up to 4 bikes. Supplied with a base set of profiles to support common bikes.

When equipped with an O2 sensor and Throttle position sensor - the logged data can be analysed to examine the Air fuel ratio against throttle openning against RPM for each gear - giving a full mapping of the Air/Fuel ratio and allowing for the fine tuning of carburetor / injector settings.

The OBD Bridge is designed to work with just about any motorcycle except those using CANBUS to talk to the instruments. Any analog signal going to the dash can be measured an sent / logged.

This was a quick video I did as a preview to show the product - should serve to give a quick idea of how it works and options.

Video showing operation with a basic RealDash setup