I am converting a Freightliner Box truck to an RV. I'm doing the automation with HomeAssistant/ESP32home. The box is a completely enclosed aluminum and steel structure. The easy way to do things would be to use WiFi or Bluetooth to communicate between the devices/sensors and the HomeAssistant controller(s). However, I'm also a HAM operator and will be running HF/VHF/UHF/CB, etc. from the rig, hopefully using the all-aluminum roof as a ground-plane. I'll also have a microwave and other "noisy" RF sources running.
So... I'd like to have all the device communications wired, preferably on a bus so that I don't have to do end-runs back to the controller for every device. I'd also like to use ports already on simple ESP32-type devices rather than have to add additional hardware (e.g. CANBus, RS-232/485, Ethernet, etc. shields) to these simple devices.
I will be tying the HomeAssistant into the Truck's CANBus system to monitor/control the engine/transmission/lights/peripherals/etc. and would love to be able to just run a CANBus everywhere, but to my knowledge, the ESP32's don't/can't communicate natively on a CANBus without and adaptor (correct me if I'm wrong). I'd love to use the CANBus wires and piggyback communications over it, but that really sounds problematic. However, I could run a dedicated 2-wire bus for the devices if I had a native protocol that would be reliable over say 15m of twisted pair wire.
I'm relatively new to the Arduino world (and HomeAssistant - for that matter) and am looking for ideas and feedback. Powering the devices shouldn't be a problem because I'm planning on having 12v, 5v and 3.3v power busses run everywhere (with ground/common tied to the metal shell/frame) so I'm just needing reliable coms between (potentially many) devices and the HomeAssistant (RaspberryPi).
Any feedback or ideas would be great. Thanks in advance.
I suggest you rethink the multiple busses as they will act as antennas with all of the RF around. 3V3 logic wires are asking for problems, they should be through some type of interface. The MCP2515 CAN boards are inexpensive and have both the transceiver and controller on them with only a SPI interface and int to the micro. Using Cory Fowler's library could have you up in one evening, it did that for me. It is not the cheapest solution but you might ask why automotive, trucking and other industries are going that way.
If you have a noisy RF environment then the micros will need to be shielded and the power supply filtered. Adding a bus transceiver is just another task to add to the list. What could be a problem is finding non-fake transceivers as the post COVID supply chain is a mess.
Like I said, I'm new to this so I'll have to do some studying but if I understand what you're saying I should set up a CAN Bus (two wire, twisted pair) for my home automation side and pair an (MCP2515 CAN Bus Module TJA1050 Receiver SPI Module for Arduino) with each device and figure out a way to use that to pass the message traffic from my RPi HA controller...
Right now it sounds like "JFM", but I suppose I'm going to have to dive into it at some point if I want to talk to my truck's CANBus. I was hoping I could avoid custom code on most of my Arduino's since ESP32Home does such a nice job of handling things for me.
Then again, as far as I know HomeAssistant and ESP32Home rely on WiFi to communicate anyway and I'm back to the drawing board with hardwired serial interfaces regardless. Guess it's time to do some more learnin'.
It sounds like you have two distinct goals and I'm not sure there is much of an Arduino connection.
If your first goal is to connect Home Assistant to your truck's CAN bus then that is a question for the Home Assistant forum.
If your second goal is to connect a Home Assistant to multiple ESP32 devices running the ESP home firmware over a wired bus then the best place to ask would be the forums/documentation for Home Assistant and ESP home.