search terms : O2 AFR Diagnostic, Wireless Wide Band AFR Meter, Wide Band Air Fuel O2 Controller, Wide Band O2 Sensor, Bosch LSU4.9 O2 Sensor, Bosch LSU4.2 O2 Sensor, Bosch Cj125 O2 Sensor Controller, Arm Cortex-M3, LPC1347,

Wide Band Air Fuel Ratio (AFR) Meter :

For more details please visit our wiki.efiHacks.com

This Instrument uses the Bosch CJ125 O2 Sensor Control and Signal Pre-Processing Chip.
It supports both popular Wide Band Oxygen Sensors, the newer Bosch LSU4.9 and the legacy Bosch LSU4.2 type.

note : this device is brand new and we expect to be able to ship the 1st production units by end of september, make it mid november, looks like now :)

efi-O2 Meter description :

The Wireless Wide Band O2 Air Fuel Ratio Meter is the perfect diagnostic tool to analyze any Gas, Alcohol, Diesel, … based engine’s combustion process in real-time and display or record (data-logging) the result over, either a Wireless (Bluetooth SPP), or a Wired RS232 Serial Data connection, to an Android (cell phone, Tablet …), Windows or Linux based computing device by using our Application Software.

The real-time sampled and digitally filtered max Air Fuel Ration data rate is 100 Hz, 10 ms. The max binary package rate of 25 Hz, 40 ms allows for all real-time data to be either logged or displayed numerically and in graph form. What this means is that a faster sensor response can still be displayed by linear interpolation of the received data

The current design put’s major focus on dynamic measurement response rather than precise high resolution data. The data can also be output as a linearized analog 0 V – 5 V voltage with the 10 ms sensor sample data rate.

The output data range can be scaled to various popular measurement units.

  1. lambda 0.65 – 1.5 : spark ignited engines running on gas, or similar
  2. lambda 1.0 – 10.0 : diesel engines always using the full displacement volume of air
  3. AFR 10.0 – 20.0 : spark ignited engines, scaled in a air / gasoline, ethanol … ratio measurement units.
  4. O2 % 0.0 – 21.0 : used for other processes (heaters, etc …) which only use a small percentage of oxygen. The data output is scaled in percent of O2 measurement units.
  5. Software Selectable Range and Meas. Units : any range and linear lambda type units within the measuring capabilities of the LSU 4.x sensor.

A narrow band sensor  simulated output with programmable trigger points and programmable output voltage limits is also available. This nbO2 simulation output is not system ground based and can be referenced to an external virtual ground

Bosch LSU 4.9 wbO2 Sensor and efi-O2Meter with CSR Bluetooth Radio, bottom view

Bosch LSU 4.9 wbO2 Sensor and efi-O2Meter with CSR Bluetooth Radio, bottom view

Below are some of the various options the efi-O2 Meter can be ordered as … additional accessories are at our efi-O2 Meter Accessories page.

efiO2Meter ABS Plastic translucent blue, LSU4.9 Wide Band O2 Sensor

efiO2Meter ABS Plastic translucent blue, LSU4.9 Wide Band O2 Sensor

well … we are gearing up for production and will have the promised list of order options available soon … sorry for the delay … all i can say is that we’re very happy the way the design turned out so far … features better than expected, price unfortunately higher than expected

Android Control App :

The efi-O2Meter is designed to connect wireless via a built in Bluetooth module to most Android 4.1 and on up Phones and Tablet Computers to provide numerical, bar-graph and 8 channel X/Y plot real-time data display. The X/Y plot contains a 60 sec history buffer and a SD-Memory based Data-Logging for long time-span data recording.

Our App can be directly down-loaded and installed from the Goooooooogle Play-Store into your Android Device of choice, most 4″ phones, 7″ and 10″ tablets.

The following link is frequently updated to reflect the design progress of our Android App, as long as we do not write a new post.

efiO2Meter Android App Test Download

Android App Main Screen

Android App Main Screen

More details can be found at our wiki.

Operations Principle :

The efi-O2Meter’s wide band O2 Sensor measures the remaining oxygen content or lack thereof, in form of incompletely combusted fuel concentration, in the exhaust gas and calculates the engine’s Air Fuel Ratio.

Supported Sensor Types :

Available Sensors are both, the new and overall improved Bosch LSU 4.9 over the older Bosch LSU 4.2 type and the older one.

One convincing example of comparison are the measured Lambda calibration reference points for each sensor, taken from the original Bosch Sensor Data Sheets.

Bosch LSU 4.9 : a total of 25 data points

0.650, 0.700, 0.750, 0.800, 0.822, 0.850, 0.900, 0.950, 0.970, 0.990,  1.003,  1.010, 1.050,
1.100, 1.132, 1.179, 1.429, 1.701, 1.990, 2.434, 3.413, 5.391, 7.506, 10.119, 30.000

Bosch LSU 4.2 : a total of 10 data points

0.700, 0.800, 0.850, 0.900, 1.009, 1.180, 1.430, 1.700, 2.420, 30.000


efiO2Meter - All Possible Connections

efiO2Meter – All Possible Connections

… more to come …