Page 1 of 31

Nano Lambda wideband controller based on cj125

Posted: Wed Sep 05, 2018 7:45 pm
by ruzki
I´ve made a very naive approach of designing a Lambda controller board wich is based on a Bosch cj125 chip.
The board will be soldered to an Arduino Nano.
At the current state it has one PWM driven analog output and 2 DAC´s.

We ordered 10 pieces of PCB and will start testing this Board soon.

It would be great if somebody could take a look at the code.
Maybe in future this code could be implemented to the Speeduino code.

All KiCad project Files can be found here:
https://github.com/chaosteam/Nano_Lambda

Let me know what you think.
Nano_Lambda.jpeg
Nano_Lambda.jpeg (157.36 KiB) Viewed 27764 times
UPDATE 10.04.2020

The Arduino based Nano Lambda Board has been extensively tested and is working as expected.

Alfagt has made an superb firmware for the Nano Lambda which can be found here:
https://github.com/TurboCorse/LambdaCtrl
For my understanding, there is no Controller out there with such extensive adjustment capabilities.
Via TunerStudio it is very easy to connect and tune. One can tune the analog outputs to compensate non linear behaviour and offset error.

tooly made an very convenient and easy to build Board named BL49SP. It is an 2-Layer Board with components only on one side, which make it also inexpensive to build. The Gerbers Files as well as Schematic can be found here:
https://github.com/oelprinz-org/BL49SP

Alfagt made an non open source Lambda Controller based on his firmware and improved hardware -BL49 by tooly- which has an extensive set of CAN functionalities as well as extended configuration options which I think are unique for an Lambda Controller. For more information check this Link:
https://www.turbocorse.at/can-bus/micro-lambda/

Please post a comment or picture if you have build one Nano Lambda or BL49SP Bard.

Re: Nano Lambda wideband controller based on cj125

Posted: Wed Sep 05, 2018 7:56 pm
by ruzki
and a schematic as pdf-file..
(219.39 KiB) Downloaded 1620 times

Re: Nano Lambda wideband controller based on cj125

Posted: Wed Sep 05, 2018 8:22 pm
by Kenai
Following! this looks very promising

Re: Nano Lambda wideband controller based on cj125

Posted: Wed Sep 05, 2018 10:29 pm
by LPG2CV
+1 :)

Re: Nano Lambda wideband controller based on cj125

Posted: Fri Sep 07, 2018 10:16 am
by flat4power
Hi,

I didn't find the code ?
Can you send me it ?

Re: Nano Lambda wideband controller based on cj125

Posted: Fri Sep 07, 2018 10:49 am
by chaoschris
Hello flat4power,
the code will be published soon when it is running on this platform. Please give us some days as the boards haven't arrived at this moment.
Most of the code has been taken here: https://github.com/Bylund/Lambda-Shield-Example
When it is running, everybody is invited to bring in his own ideas. I'm seeing a multi-Lambda-Controller on a Selfmade AVR Board for example (with two or four WB Controllers).
Best regards
Chris

Re: Nano Lambda wideband controller based on cj125

Posted: Sun Sep 09, 2018 5:01 pm
by EdGi
This looks very interesting. What data do you have about driving the sensors?

On this layout, you might have problems with the heater current switching interfering with the other signals, as they have a shared GND across the board.
Might not be a problem, but if it is try connecting your +12V & GND power connections directly at the heater end of the board.

Re: Nano Lambda wideband controller based on cj125

Posted: Sun Sep 09, 2018 6:22 pm
by bylund_automotive
Good one, let me know if you have any questions on the code or our original hardware. Both our schematics and code is GPL licensed just for this reason.

Re: Nano Lambda wideband controller based on cj125

Posted: Thu Sep 13, 2018 6:45 pm
by ruzki
Made a very stupid mistake.
I´ve used a wrong footprint for the CJ125 :roll:
Nano_Lambda_FAIL.jpeg
Nano_Lambda_FAIL.jpeg (149.88 KiB) Viewed 27501 times
@EdGi
i am not sure about your question.. We have got an old 40 page datasheet for the CJ125 chip. This is our basis.
Yes, there is a very good chance this will happen. Thanks for the advice! We will try like it is right now and will report.

@bylund_automotive
Thank you very much Christian.

Re: Nano Lambda wideband controller based on cj125

Posted: Sun Sep 30, 2018 6:48 pm
by ruzki
I´ve tested the first running Prototype this weekend.
So far things are looking good, lambda values seem to be plausible.

- Pinout is different compared to Arduino Uno.
- UBAT_MIN was set from 550 to 400 due to different resistor values for Battery voltage ADC

- Footprint for Diode U4 is wrong, diode needs to be turned on the PCB(already changed on GitHub)
- Digital Voltage Output via Op-amp seems not to work

Now we will have to tune the Arduino sketch.
y%X1Iw6aQH6T2IaWXMDddg_thumb_115b6.jpg
y%X1Iw6aQH6T2IaWXMDddg_thumb_115b6.jpg (302.71 KiB) Viewed 27287 times
sjevPvmTTRyGXvqY5mSkFA_thumb_115b5.jpg
sjevPvmTTRyGXvqY5mSkFA_thumb_115b5.jpg (303.2 KiB) Viewed 27287 times