DIY CAN bus for Camper/RV systems monitoring and control


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Thought Club
based on this tutorial:
using the attached Arduino Library, and some SPI MCP2515 modules.

i may also use some of these modules for remote sensors:

the master unit will be a Arduino MEGA2560 Core dev-board. i will use a Nextion 7" touchscreen for control and display. for cold weather, the master unit will be equipped with a heater to preheat the Nextion screen so the furnace can be turned on.

I have several DS18B20 temp sensors that can be used easily to read the temperature of several areas, and even epoxied to the tanks to check their temperatures, if really cold, though will likely be dry-camping if too cold. ;)

so i can monitor temps for compartments, tanks (including LP), rooms. monitor battery volts. monitor tank levels.
i can also control the furnace thermostat (or rather, be it), battery charger connection, water pump on/off, water heater on/off (maybe).

the thermostat can just take the main-room temp, while just monitoring the other rooms, as there is only one heat-zone anyway.
battery volts can be monitored at the main unit, as it needs battery power to function anyway, and it will be a good measure of system volts. the accurate voltage reading will likely be from my volt/coulomb meter anyway.
total system power will be powered when the camper has power. i will create a screen-blank style screensaver, where the screen will simply dim to 0 when not used for so long. it will also switch to a blank page on the nextion where the whole screen is a button. simply tap to restore the screen.
I may end up having to upgrade the screen to the one with more memory... ;)

tank levels will be read over CAN, remote temps over CAN, remote relays over CAN...

battery charger... turn on at a min of X volts. plain and simple... if the solar isn't keeping up, turn on the charger. will factor for a charger override too, to keep from cycling the battery too much. IOW, if i am drawing more than so many amps at a given time, over ride the charger and turn it on. if on override, and amps drop back, turn off after the battery reaches normal charge volts. starting to wish my charger had status outputs... ;) it does have a "status LED", but i don't know what it operation is specified at.



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making a change... i have some packet radio (900Mhz) modules, and i think i will use a pair of them on this project. so i will have a bast station that collects the data from the sensors, and then sends the data via RF to the display. the display will be just a Nextion screen, radio module, and a Mega2560.
with this, i can also use less CAN devices, if any. because the base station can be placed closer to the sensors, rather than having to be on display with a Nextion screen. the display will be made moveable, with just a 12Vdc plug-in to the camper.