question

wedgehog avatar image
wedgehog asked

Is there a tank level sensor for heating Oil that will work with the Cerbo GX please

I have one of those radio linked floating sensors that gives a bar graph display of the level, but it's not very accurate, I would like an accurate display of my heating oil on the Cerbo, but after an hour of searching and reading all I find is water and LPG tank sensors?

cerbo gxtank monitor
2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

10 Answers
wedgehog avatar image
wedgehog answered ·

Tap Tap! Hellooooo is anyone there?

2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Jeremy Albrecht avatar image
Jeremy Albrecht answered ·

Is there any reason a water or LPG level sensor wouldn't work for you? One of the Mopeka bluetooth sensors for example?

2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

wedgehog avatar image
wedgehog answered ·

Hi Jeremy, Don't think I could use a water sensor in heating Oil it might attack the components, they call it Oil, but it's not really much different to jet aviation fuel. I'm not sure how the LPG sensors work, I know they are detecting it in it's liquid form, but surely it's not inside the tank? you would let all the gas out fitting it? I will have a look at them. Bob

9 comments
2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Jeremy Albrecht avatar image Jeremy Albrecht commented ·
Bob,


The Mopkea sensors are ultrasonic and attach to the outside of the tank. It really shouldn’t matter what kind of liquid it is, as long as the sensor can see through the tank properly.

0 Likes 0 ·
wedgehog avatar image wedgehog Jeremy Albrecht commented ·
Just had a look, good sensor but unfortunately not suitable for the Victron Cerbo-GX it requires a resistive device, like a car fuel tank sensor, as it requires two wires to connect to the Cerbo and the Cerbo measures the changing resistance between the wires
0 Likes 0 ·
Jeremy Albrecht avatar image Jeremy Albrecht wedgehog commented ·
The Mopeka sensors are Bluetooth, they require no wiring.
1 Like 1 ·
Jeremy Albrecht avatar image Jeremy Albrecht wedgehog commented ·
Sorry, I should have been more clear, the Cerbo GX supports the Bluetooth Mopeka sensors out of the box.
0 Likes 0 ·
wedgehog avatar image wedgehog Jeremy Albrecht commented ·
Hi, ok thank you I have investigated further after you said that and indeed the can connect directly to the Cerbo and would be perfect, but as always there is a "BUT" from what I can see they have to go on the bottom of the tank, that I cannot do because my 1200 ltr heating oil tank is sat on the concrete and it is what is called a "Bunded" tank it's for safety, what it means is that you have a tank within a tank, two skins, and there is no way to access the internal tank with the oil in it from outside other than through the top. I am working with Matt in the other thread here, My tank has a sensor already it's ultrasonic and is in the top, it sends a signal on 433mhz to a receiver decoder in the house which has a little bar graph display, Using an ESp32 and some clever software we can intercept that signal and re direct the MQTT information to the Cerbo, I think this system is best suited as it uses the sensor already in the tank and from the top. Thank you for you help and it's not wasted as I was not aware of this sensor and will probably use it for something else. Bob
0 Likes 0 ·
derrick thomas avatar image derrick thomas wedgehog commented ·
Have you looked at the mopeka td40? It is a top mounted sensor.
1 Like 1 ·
wedgehog avatar image wedgehog derrick thomas commented ·
Hi, funny you should say that, I have spent over an hour trying to find one, I have asked Mopeka if they ship to the UK



0 Likes 0 ·
Jeremy Albrecht avatar image Jeremy Albrecht wedgehog commented ·
Perhaps Amazon?
0 Likes 0 ·
wedgehog avatar image wedgehog Jeremy Albrecht commented ·
First place I looked, they have some but not that one



0 Likes 0 ·
matt1309 avatar image
matt1309 answered ·

Hi @wedgehog

I have an Apollo oil sensor they use radio signals to send data from ultrasonic sensor on top of heating oil tank to a small plug/display that's inside the house. I capture this radio frequency using this:

GitHub - merbanan/rtl_433: Program to decode radio transmissions from devices on the ISM bands (and other frequencies)

Which is running a separate raspberry pi and then forward it to gx device via MQTT.

Only thing i needed to do on GX device was use the dummy script to make a "virtual tank"

velib_python/dbusdummyservice.py at master · victronenergy/velib_python · GitHub


I imagine you could technically install rtl_433 on the venus os device itself. You'll likely also need to install the drivers for the SDR.


68 comments
2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

wedgehog avatar image wedgehog commented ·
Thanks Matt, I will have a look at that.
1 Like 1 ·
matt1309 avatar image matt1309 wedgehog commented ·

No worries,

I think there's some arduino devices that folk have made to forward on the RTL_433 to mqtt. Using openMQTT I'm not too familiar with making/configuring arduino like devices so just went with raspberry pi zero and just used a script for forward that rtl_433 received onto gx device. (if you go this route double check the oil sensor you have is in the arduino version of the program)


There's a list of sensors on there the rtl_433 site that it works with but where i am (UK) almost all the oil sensors I've seen are Apollo (even if they're not the protocol is identical so works as though it was)

GitHub - NorthernMan54/rtl_433_ESP: Trial port of the rtl_433 Library for use with OpenMQTTGateway on a ESP32 and a CC1101 Transceiver

1 Like 1 ·
wedgehog avatar image wedgehog matt1309 commented ·
Ahh! I have found a youtube about it, I have ordered the required module and will let you know how I get on, If I get stuck will you give me some advice please Matt



1 Like 1 ·
Show more comments
dansonamission avatar image
dansonamission answered ·

One of these connected to VE.CAN

https://www.maretron.com/products/tlm100-tank-level-monitor-40-depth/

1 comment
2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

wedgehog avatar image wedgehog commented ·
Thank you I will have a look
0 Likes 0 ·
wedgehog avatar image
wedgehog answered ·

How do I forward the MTQQ from a Lilygo 433 to a Victron Cerbo-gx


2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

matt1309 avatar image
matt1309 answered ·

Hi @wedgehog


Here's how you setup a virtual tank. You can then write the litres values to this. (If you can edit the output received from ultrasonic oil sensor to just send litres to mqtt topic then you wont need any other devices).


Victron has a more detailed guide here, which explains how you can make the below more robust, and get the drivers to persist over updates etc, however the below works.

So you start with Victrons custom driver but edit it to make it create a tank

#!/usr/bin/env python3

"""
A class to put a simple service on the dbus, according to victron standards, with constantly updating
paths. See example usage below. It is used to generate dummy data for other processes that rely on the
dbus. See files in dbus_vebus_to_pvinverter/test and dbus_vrm/test for other usage examples.

To change a value while testing, without stopping your dummy script and changing its initial value, write
to the dummy data via the dbus. See example.

https://github.com/victronenergy/dbus_vebus_to_pvinverter/tree/master/test
"""
from gi.repository import GLib
import platform
import argparse
import logging
import sys
import os

# our own packages
sys.path.insert(1, os.path.join(os.path.dirname(__file__), '/opt/victronenergy/dbus-systemcalc-py/ext/velib_python'))
from vedbus import VeDbusService

class DbusDummyService(object):
    def __init__(self, servicename, deviceinstance, paths, productname='Thunderstorm Tank', connection='Dummy service'):
        self._dbusservice = VeDbusService(servicename)
        self._paths = paths

        logging.debug("%s /DeviceInstance = %d" % (servicename, deviceinstance))

        # Create the management objects, as specified in the ccgx dbus-api document
        self._dbusservice.add_path('/Mgmt/ProcessName', __file__)
        self._dbusservice.add_path('/Mgmt/ProcessVersion', 'Unkown version, and running on Python ' + platform.python_version())
        self._dbusservice.add_path('/Mgmt/Connection', connection)

        # Create the mandatory objects
        self._dbusservice.add_path('/DeviceInstance', deviceinstance)
        self._dbusservice.add_path('/ProductId', 0)
        self._dbusservice.add_path('/ProductName', productname)
        self._dbusservice.add_path('/FirmwareVersion', 0)
        self._dbusservice.add_path('/HardwareVersion', 0)
        self._dbusservice.add_path('/Connected', 1)

        for path, settings in self._paths.items():
            self._dbusservice.add_path(
                path, settings['initial'], writeable=True, onchangecallback=self._handlechangedvalue)

        GLib.timeout_add(1000, self._update)

    def _update(self):
        with self._dbusservice as s:
            for path, settings in self._paths.items():
                if 'update' in settings:
                    update = settings['update']
                    if callable(update):
                        s[path] = update(path, s[path])
                    else:
                        s[path] += update
                    logging.debug("%s: %s" % (path, s[path]))
        return True

    def _handlechangedvalue(self, path, value):
        logging.debug("someone else updated %s to %s" % (path, value))
        return True # accept the change


# === All code below is to simply run it from the commandline for debugging purposes ===

# It will created a dbus service called com.victronenergy.pvinverter.output.
# To try this on commandline, start this program in one terminal, and try these commands
# from another terminal:
# dbus com.victronenergy.pvinverter.output
# dbus com.victronenergy.pvinverter.output /Ac/Energy/Forward GetValue
# dbus com.victronenergy.pvinverter.output /Ac/Energy/Forward SetValue %20
#
# Above examples use this dbus client: http://code.google.com/p/dbus-tools/wiki/DBusCli
# See their manual to explain the % in %20

def main():
    logging.basicConfig(level=logging.DEBUG)

    from dbus.mainloop.glib import DBusGMainLoop
    # Have a mainloop, so we can send/receive asynchronous calls to and from dbus
    DBusGMainLoop(set_as_default=True)

    pvac_output = DbusDummyService(
        servicename='com.victronenergy.tank.ttyO1',
        deviceinstance=0,
        paths={
            '/Capacity': {'initial': 1.235},
            '/Level': {'initial': 0},
            '/Status': {'initial': 0},
            '/Remaining': {'initial': 0},
            '/FluidType': {'initial': 4},
            '/Standard': {'initial': 2}
        })

    logging.info('Connected to dbus, and switching over to GLib.MainLoop() (= event based)')
    mainloop = GLib.MainLoop()
    mainloop.run()


if __name__ == "__main__":
    main()


Edit initial values. Can also edit tty01.

This file should be saved in data folder. I make another folder to store it all in called virtTank

/data/virtTank/virtualTankTTY01.py

You also need to create a folder

/data/virtTank/service

inside this folder you will make a file named run

run will contain:

#!/bin/sh
python /data/virtTank/virtualTankTTY01.py

Then you need to create a symlink in /service to the folder /data/virtTank/service


This would be done using command:


ln -s /data/virtTank/service/ /service/virtTank/


You should then see a folder be created in /data/virtTank/service/ called supervise and a tank appear in dbus-spy (and on VRM).


There are more details on victron's github about making the above more robust and to persist over updates as well as storing the drivers in /opt/victronenergy however for a simple setup the /data folder is fine. If you're adding more complex programs keeping things neat and stored in correct folders will matter more. Similarly if persisting over updates is critical then read further here:

https://github.com/victronenergy/venus/wiki/howto-add-a-driver-to-Venus

I'm not too bothered with my setup breaking over updates as redoing the above is quick enough once you've done it once.


Now the virtual tank is in venus os/GX device. However you need to get data values into it.

I do this via MQTT.

The topic you'll need to send the remaining and level to are:

Remaining: /W/{VRMID}/tank/{deviceID}/Remaining

Level: /W/{VRMID}/tank/{deviceID}/Level


Where VRMID you can find in settings->VRM Online Portal
of your GX device

And device ID you can either find in GX device list or VRM device list And i believe it's VRM instance ID. If you just copy the above scripts it will be 0.


Hope this helps. Of course you'll need to somehow format the output of the oilsensor that's read by the arduino into level and remaining before sending into victron's mqtt topics that I've noted above.



2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Al avatar image
Al answered ·

@wedgehog This all looks very complicated..

Can't you just use a normal 0-190 Ohm pressure sender and manually set the range in the Cerbo.

Something like this can be mounted on a tee on the tank outlet pipe:

https://wema.co.uk/products/pressure-sender

Loads of similar on Amazon etc.

1 comment
2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

wedgehog avatar image wedgehog commented ·
May be complicated, but it's working fine, why not do it your way and show us it's better?
0 Likes 0 ·
matt1309 avatar image
matt1309 answered ·

Hi @wedgehog


What file did you use for your lilygo. I've got my custom code running (it's picking up neighbors weather station and a few other devices around the area but not the oil sensor that it's literally right next to).


At first i thought it was because i was compiling with OOK instead of FSK. However I've done that now and still doesnt seem to work (magnet trick doesnt work on mine so i'm having to test once per hour).


I noticed the FSK prebuilt file uses 915mhz not 433. Was curious which file you used.

2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

wedgehog avatar image
wedgehog answered ·

@matt1309 Hi mate, Upload, upload from the web, Lillgo_rtl_433-fsk. Oh! and don't forget, your tank may only send info a few times a day unless you put a magnet by the internal switch on the sender unit. You can look that information up on the web site for your model of sonic sender

1 comment
2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

matt1309 avatar image matt1309 commented ·
Thanks I'd copied the build settings from that binary except for some reason that binary says its built for 915 not 433 but it wouldn't receive the data with either.


Turned out I needed to clear flash.

Data's received now. Just need to check the code that extracts the data and converts depth to capacity etc then should be done.

(unfortunately magnet trick doesn't seem to work on mine) mine seems to be some obscure model that just uses same data structure but is branded differently

0 Likes 0 ·