PelletMon - IoT for central heating boiler.

CAN issues have been resolved over the last few months.

It turned out that the problem was in the software and was related to CAN frame collisions.
The issue has been eliminated and I have returned to the native TWAI interface.

A few days ago, the PCBs arrived. Soldering under the microscope was even pleasant, however, the ESP32 module did not want to cooperate. After a few hours, however, everything worked and the board started working.

Currently, the module has been permanently mounted and has replaced the previous version.

It is worth noting that due to problems with the TWAI component, I was forced to write my own CAN handling library (based on other available on the network).

More details about the library soon :)

I'm currently working on upgraded board version, which features:

• Decreased power consumption
• ESD protection / EMC improvements
• Better connectors

I've removed fuel sensor support (never used).

I've discovered this small note in Elektronika Praktyczna written in polish about PelletMon project (11/2021). They've previously spotted another project - Energy Monitor. It's always good to read about own project in brand press. Thanks!

Great success!

Few days ago I've finished CAN component that is able to handle VideNet protocol. Adding new request takes only few lines of code.

Currently supported features are:

• Ability to turn on / turn off controller.
• Ability to read / set hot water mode.
• Ability to read / set central heating mode.
• Ability to read kettle temperature.
• Ability to read hot water temperature.
• Ability to read burner power (%).
• Ability to read fuel usage sum (kg).

Special thanks going to:

• Kem Klattrup 
• Digiplex from elektroda.pl forum

I've found Vide-Net protocol specification (VideNet is an original RC module). With that knowledge remote control is now possible!

After removing the terminating resistor, the problems with the boiler disappeared. The device has been working continuously for several days without any problems.

Final mounting - transparent enclosure, SMA antenna:

It looks like with 120 ohm resistor, I have introduced excessive termination that led to errors in CAN transmissions. I had to unsolder termination resistor from my board and trim my cables to work properly as CAN stub.

Enclosure arrived today, so I have mounted everything inside.

It requires more testing this time, but I hope that issue is fixed.

Today I prepared the cables and prototype software to retrieve data, then connected everything to the heating boiler CAN-bus and communication with MQTT worked properly.

Example dasbhoard:

Testing connection and current consumption.

What's next?

I need to route everything properly, get an enclosure and add fuel level sensor. It will take few days as I have to order cable organizers etc.

Before connecting my device to the boiler, I made sure that all interfaces were working. 

There was a problem with the R1 resistor, which made the CAN bus not working, but it turned out that it was enough to correct the weld. There is working two-way communication between the two PCBs. The fuel level sensor leads have also been tested and everything is fine.

Now all that's left is programming and installation on the boiler :)