the display node for my camper, based on a Arduino Mega clone

Charge Monitors
Batteries Monitor
Controller and Mobile Router

Fresh Water Level Monitor

Fridge Fan Controller

Display

A collection of the sensors and actuators I buit for my camper in the past year

the power supply system under the dinette seat

the battery management system (purchased) data are read via wifi by an ESP32, which reports the info to the GW via nRF24L01+.

a closed look at 2 sensors.
the one on the left reads voltage and current from the solar PV panel and to the battery management system

the one on the right reads voltage and current from/to the start and service batteriers
both sensors report instant power and energy.

Fresh water sensor reads the water level, flow and temperature.
has 4 optcoupled outputs to send the information to the 4 LEDs of the original control panel of the camper

gray water tank sensor reports water level with an ultrasound sensor. has an optocoupled output to the "full" LED of the original control panel

bettry supplied temperature and humidity sensor.
I use it in the fridge but also at home, where I have also one with BME280.

A fan controller to help the fridge to work better, controlling the condenser temperature using an optical thermometer sensor.
I have 3 other units, one in the power supply system, one in the closet and one on the roof.
They are all with a PID controller.

Some updates in almost one year.

I moved all the gateways and controller part in a most suitable location

I've created a dual current sensor for the fuse box and the inverter. Each Current sensors can withstand 90A max, so I used both channels in parallel. The sensors are defined for both Channel 1, 2 and Sum(Ch1+Ch2) to handle this case easily

Recently I made an updated version of my Photovoltaic monitor since the 20A that the old one could withstand are not enough now, so the new version is capable of 50A max. Still waiting the Hall sensors though...

Finally, I cleaned up a bit the deployment under the bench
but I am not done yet

Finally I had the time to refine it:

My RV is under restoration, so now or never. I wanted to experiment a bit out of the pure sensorics and iot and try another interesting use case:

1. 12V water boiler - in series with the Truma Combi gas boiler
2. wireless node to handle the boiler power supply (see the link above)
3. water tank loading with pre-filter, valve, pump and 1-stage filter
4. water filter, ultra-violet sterilizer, thermostatic mixer and warm water recirculation.

This new node handles the water loading, starting the valve and the pump via a push button, and stopping after 10' or when a Tank Full capacitive sensor is enabled.
A water flow sensor switches on the UVC water sterilizer for a minimum of 15' (to save power and minimize the amount of power cycles applied to the UVC lamp).

Three temperature sensors measure the temperature on the hot water delivery and return, and the connection between the Truma Combi boiler and the electric boiler.
The purpose is to keep the hot water always ready at the taps, keep the boilers water at the same temperature when needed and a few more other cases.

A pressure sensor inhibits the recirculation pump and the UVC Lamp if the pressure is too low.

This time I've pushed myself out of the comfort zone.

This is how I solved the issue of ESP32 GW hanging when WiFi connection is lost or not established. It is not 100% my original work, it has been put together using bits and pieces, but it works.

I simply use a watchdog timer:

#include "esp_system.h" // added for WDT
hw_timer_t* timer = NULL;

// WDT related
void IRAM_ATTR resetModule() {
	Serial.println("reboot\n");
	ESP.restart();
}

void WdtReset()
{
    timerWrite(timer, 0); //reset timer (feed watchdog)
}

void StartWatchDog()
{
    timer = timerBegin(0, 240, true); //timer 0, div 80
    timerAttachInterrupt(timer, &resetModule, true);
    timerAlarmWrite(timer, 5000000, false); //set time in us
    timerAlarmEnable(timer); //enable interrupt
}

IPAddress ConnectWiFi()
{
    Serial.println();
    Serial.println();
    Serial.print("Connecting to ");
    Serial.println(MY_WIFI_SSID);

    /* Explicitly set the ESP to be a WiFi-client, otherwise, it by default,
       would try to act as both a client and an access-point and could cause
       network-issues with your other WiFi-devices on your WiFi-network. */
#ifdef ESP32
    WiFi.persistent(false);
    WiFi.mode(WIFI_STA);
#endif // ESP32

    WiFi.begin(MY_WIFI_SSID, MY_WIFI_PASSWORD);


    while (WiFi.status() != WL_CONNECTED) {
        digitalWrite(LED_BUILTIN, LED_ON);
        wait(500);
        Serial.print(".");
        digitalWrite(LED_BUILTIN, LED_OFF);
        wait(500);
    }

#ifdef ESP32
    WiFi.setAutoReconnect(true);
#endif // ESP32

    return WiFi.localIP();
    
}
void before()
{

    StartWatchDog();

    // We start by connecting to a WiFi network
    localIP = ConnectWiFi();
    myHostname = WiFi.getHostname();

    WdtReset();

    Serial.println("");
    Serial.println("WiFi connected");
    Serial.println("IP address: ");
    Serial.println(localIP);
    Serial.println(myHostname);

// do other stuff ...

}

void loop()
{
   

    // check WiFi connection
    if (WiFi.status() != WL_CONNECTED) return; // the WDT is not reset
    WdtReset();

// do other stuff ...
}

Hope it helps

A simple node to enable/disable the 12V power supply to auxiliary non vital loads (e.g. water boiler) based on the service battery voltage. A relay is controlled by the presence of a charging source.
Additionally, in presence of other charge sources, the Mains Charger is disconnected from the Service Battery. The Mains Charger relay is enabled if there are no other charge sources and the camper is connected to the Shore Power.

There are 2 additional analog voltage input.

I tend to create edge nodes, with full capability of serving the desired use cases, even if Gateway/Controller are down. In this case I can Arm/Disarm some automations from the controller using S_DOOR sensor types.

In my RV I use #mysensors and #mycontroller V1.

A few times I wished I could switch on/off remotely a few subsystems (water, solar, geofencing and alarms to name a few) without needing to access mycontroller from remote.

So I took off from my ideas shelf an old experiment with Fauxmo and Alexa Echo Dot gen 3.

Alexa Echo Dot embeds a WiFi gateway for Hue lights. Fauxmo Arduino library allows to fake these lamps, and works on ESP8266 and ESP32. Perfect for our MySensors.

So I simply created a Mysensors Gateway with 16 Dimmer local sensors, and added the Fauxmo library and created 16 fake ("faux") lamp devices.
When an Alexa event is detected, and the event send()s the lamp status to the controller.
When the GW receive()s a dimmer sensor event from the controller, the dimmer state is sent to Alexa.

Alexa needs to receive a device update at least every minute, so a simple software timer in the loop() is in charge for this.

A couple of years ago I created a BLE - Mysensors Gateway which scans my Gas Tank sensors over BLE and sends the sensors data to the Controller.

Both projects consist of ESP32 dev boards without any additional HW, in a nice and simple 3D printed enclosure bought on Ebay.

This is my temperature-humidity-pressure sensor in a 1151v3wh enclosure.

@OldSurferDude yes, you are correct. this sensor is capable of 50A continuous, which safely I would make it working at 40A max., but for such an important load as in your case I would go for a beefier one, like the ACS75x, 77x, but at this point I would also change the node's form factor for space and insulation reasons.

On my application on the RV I have a max. curr. of 13A running on a AWG14-16 cable (European rules for RVs), so I did not ask myself too many questions beside, of course, safety.

About the signal, it will be a sinusoidal signal swinging around Vcc/2.
Vcc can be easily measured internally on the ATmega328. On all my DC sensors I measure Vcc at every loop, just before measuring the ADCs.

Honestly, when the space is not an issue like in my RV, I would rather use a ring core current transformer, and I would get rid of noise, response time, power dissipation, but over all no need to cut any cable.

Long story short, it has been a nice experiment and I used it for 6 months, and then I switched back to my RF-NANO based RS485-Modbus - Mysensors bridge connected to an off-the shelf power analyzer.

Just for fun I attach a pic of my 12Vdc sensors installed on my RV. Forgive me for the spaghetti wiring on the right side, but this is an area that needs improvement.

@OldSurferDude thank you !

I saw on your git page that you were looking for a HW.
@OldSurferDude would something like this work ? The schematic is very similar.
I would just need to move the current sensor a bit far from the connector, in case of a new PCB order is required

@hlehoux thank you

In my RV I use #mysensors and #mycontroller V1.

A few times I wished I could switch on/off remotely a few subsystems (water, solar, geofencing and alarms to name a few) without needing to access mycontroller from remote.

So I took off from my ideas shelf an old experiment with Fauxmo and Alexa Echo Dot gen 3.

Alexa Echo Dot embeds a WiFi gateway for Hue lights. Fauxmo Arduino library allows to fake these lamps, and works on ESP8266 and ESP32. Perfect for our MySensors.

So I simply created a Mysensors Gateway with 16 Dimmer local sensors, and added the Fauxmo library and created 16 fake ("faux") lamp devices.
When an Alexa event is detected, and the event send()s the lamp status to the controller.
When the GW receive()s a dimmer sensor event from the controller, the dimmer state is sent to Alexa.

Alexa needs to receive a device update at least every minute, so a simple software timer in the loop() is in charge for this.

A couple of years ago I created a BLE - Mysensors Gateway which scans my Gas Tank sensors over BLE and sends the sensors data to the Controller.

Both projects consist of ESP32 dev boards without any additional HW, in a nice and simple 3D printed enclosure bought on Ebay.

My RV is under restoration, so now or never. I wanted to experiment a bit out of the pure sensorics and iot and try another interesting use case:

1. 12V water boiler - in series with the Truma Combi gas boiler
2. wireless node to handle the boiler power supply (see the link above)
3. water tank loading with pre-filter, valve, pump and 1-stage filter
4. water filter, ultra-violet sterilizer, thermostatic mixer and warm water recirculation.

This new node handles the water loading, starting the valve and the pump via a push button, and stopping after 10' or when a Tank Full capacitive sensor is enabled.
A water flow sensor switches on the UVC water sterilizer for a minimum of 15' (to save power and minimize the amount of power cycles applied to the UVC lamp).

Three temperature sensors measure the temperature on the hot water delivery and return, and the connection between the Truma Combi boiler and the electric boiler.
The purpose is to keep the hot water always ready at the taps, keep the boilers water at the same temperature when needed and a few more other cases.

A pressure sensor inhibits the recirculation pump and the UVC Lamp if the pressure is too low.

This time I've pushed myself out of the comfort zone.

A simple node to enable/disable the 12V power supply to auxiliary non vital loads (e.g. water boiler) based on the service battery voltage. A relay is controlled by the presence of a charging source.
Additionally, in presence of other charge sources, the Mains Charger is disconnected from the Service Battery. The Mains Charger relay is enabled if there are no other charge sources and the camper is connected to the Shore Power.

There are 2 additional analog voltage input.

I tend to create edge nodes, with full capability of serving the desired use cases, even if Gateway/Controller are down. In this case I can Arm/Disarm some automations from the controller using S_DOOR sensor types.

Finally I had the time to refine it:

Given the chip shortage of ATmega328, would the ATmega4809 architecture support be developed ?
The advantages of Arduino Nano Every is undeniable for non-battery-supplied nodes