Troubleshooting

[Christian_Bylund]

If you are experiencing problems please follow these steps:
1. Check connections - See this video.
2. Are you using a genuine Arduino Uno?
3. Are you using a genuine Bosch LSU 4.9 sensor?
4. Are you powering the Arduino by an unstable 5V? - See this video.
5. Have you updated the Arduino Uno WiFi firmware to the latest version? See this support thread.
6. If you get an error with code size on Arduino Uno WiFi, use ArduinoBLE library v.1.2.2.

[Redrock55]

using lamda shield 2 GUI code the numbers on the OLED screen don't make sense to us showing 148 AFR when they should show 20 or less ???
using lamda 2 example code data logger/single band gauge with RC circuit 220uf capacitor and 1.5k resistor the gauge just shows 12.3 to 12.5 then flashes to 10.0 and the volt light goes out.not reading the AFR.
Do you have a diagram for using a wide band gauge with the wide band sensor ?

[Christian_Bylund]

using lamda shield 2 GUI code the numbers on the OLED screen don't make sense to us showing 148 AFR when they should show 20 or less ???
using lamda 2 example code data logger/single band gauge with RC circuit 220uf capacitor and 1.5k resistor the gauge just shows 12.3 to 12.5 then flashes to 10.0 and the volt light goes out.not reading the AFR.
Do you have a diagram for using a wide band gauge with the wide band sensor ?

Hello,

AFR 148 / λ 10.1 is the highest value presented on the display, it sounds like you are measuring free air. What gas are you measuring?

The narrowband AFR gauges usually just measure between lambda λ 0.8-1.2 / AFR 10-20.

To test your display and gauge you can simulate λ 1 / AFR 14.70 by changing the UpdateInputs() function and hard coding adcValue_UA:

Code: Select all

//Function to read inputs and update values.
void UpdateInputs() {

  //Update CJ125 diagnostic register from SPI.
  CJ125_Status = COM_SPI(CJ125_DIAG_REG_REQUEST);

  //Update analog inputs.
  adcValue_UA = analogRead(UA_ANALOG_INPUT_PIN);
  adcValue_UR = analogRead(UR_ANALOG_INPUT_PIN);
  adcValue_UB = analogRead(UB_ANALOG_INPUT_PIN);
  
  adcValue_UA = 307; /* Hardcoded to display lambda 1 */
}

Your gauge should now display AFR 14.7 if it is accurate. Also the display should show λ 1 / AFR 14.70.

Hope it helps.

[Redrock55]

Yes we are reading free air but it should it read 10-20? But it shows 148 on the OLED with Data logger GUI front end program. Will it read 10-20 if its installed in the exhaust pipe? ( 4 stroke combustion engine)

We now tried the data logger/single band gauge program( Dyno racing from your video) it doesn't display the ARF like it show in the on the data logger or the serial monitor .

not sure what this means (AFR 148 / λ 10.1 is the highest value presented on the display)

[Christian_Bylund]

Yes we are reading free air but it should it read 10-20?

Air will not display the air fuel ratio of 10-20. Air is 20.95% oxygen, air fuel ratio of 20 (λ 1.36) is around 4-5% oxygen. The lambda sensor is measuring around 21% oxygen in clean air, the maximum value that can be displayed is λ 10 = AFR 148 which is approximately 18% oxygen if I am not mistaken. Likewise, the narrow band lambda gauge signal can display up to AFR 20 but that is the maximum for the gauge (1V).

So, if the measured signal is out of range we display the maximum value the display or gauge can handle. If you want the absolute value use the serial output or any of the apps. This is typically not a problem in automotive applications as you are usually within this range.