Scott Bender - Any recommendations for for a le...
Any recommendations for for a level sensor for this black water tank. Prefer commercial, but will DYI if needed.
66 Replies
If you’re okay with just a few different levels then a non contact sensor array would be the best approach. You don’t have to drill any holes. I found freshwater needs a percent but for blackwater I just want to know if I’m half full and 90 percent full so I know I only have one or two more flushes
Did you read the latest blog? I hear there’s a zigbee sensor for this
Oh!!
@Greg Young do have a link to the sensor you used?
ali express ,, search for “ME201WZ zigbee ultrasonic water sensor” .
you will need to have a zigbee gateway installed … i already had this setup, so adding the above sensor was v simple..
my blog gives all the details for the USB zigbee donglle setup (same source as above)
if you want to go commercial,
according to cerbo manual, there is a bluetooth wireless one that will work natively with Cerbo (“mopeka” … i have no experience with this one)
🙂 if you go the zigbee route … pickup some other zigbee sensors ! inexpensive fun! … coz i know you will tinker!
Yeah. Thanks. Here I go down another rabbit hole!
For the blogs im writing, i catalogued my devices and respective signalk wireless interfaces….
wifi, bluetooth and zigbee.
it got kinda scary.
but the reality is that different types of devices, sensors etc lend themselves better to one or other of the mainstream wireless technologies … along with OEM choices … eg most of my victron devices have bluetooth (or hardwired)
.. so thats what got me there …
@Greg Young how big is that tank sensor? It sounds like it is six inches?
your challenge may be its “height” … ie 40mm (1 1/2”) above tank surface
also to note… it has a “dead zone” where it will not read ~50mm from its face.
so if you want to measure absolute 100% level, you need to mount it so that at 100% full, there is still 50mm gap to surface of liquid.
.. however (in my case) … i just loose that last 10% … hey when the tank is at 90% … you need to be looking for a solution to empty anyway 🙂
ok, that's better
spec says 0.1 to 4m… in my testing it works down to around 0.05m (50mm)
everything I found said like 6", I think that's the packaging
yep
Does it have to be in contact with the tank?
see my picture above, I don't have enough room
yes,,, you have to cut a hole in tank for it to work (ultrasonics)
oh
shit
yes saw that … you need reasonable access to the top of tank - to cut a hole, mount it ..
i think you will have to go with the “side mount” sensors (that dont need a hole in tank.. just sticvk on surface)
you put a few sensors so you get a few steps…
and I have three coming...
will be fine with the fresh water tanks
three?
two fresh water and the black
nit going to work for the black
ah you ordered 3 ultrasonic units … going big!
two fresh tanks?
yes
not interconnected?
they are
then you should only need one … but calibration will be weird
I have more than enough sensors now! lol
I wonder what I can do for the black water
nonsense … you can never have too many … i just keep finding more to add…
but ive spilt into more WSK dashboards … haha
given your obviously investing in a zigbee interface ..
get some zigbee “door/window sensors” … great for hatches (did you read my blog? 🙂
don't worry, I went a little cray with the zigbee...
i knew it !
i have to say, i was dubious at first, but they just work! and ive had no drama with them to date
do you have any ideas how to deal with my black water tank
im working on it for you ..
Questions :
top access - no
bottom access?
height of tank?
tank vol (approx?)
it is so easy to access... but I can't tell visually
?
did you see the picture above
it's mounted vertically
yep… so its around 0.6m deep?
looks like it in a locker
24inches?
.9 meters tall
so, you definitely cant mount sensor “on top” ?
its tall but smaller footprint…
so if side mounting “proximity” sensors … for any sort of decent accuracy your going to need 5+ ish side mounted sensors..
not enough room between the connections at the top
I'd probably be ok with three
what would those sensors be?
fine. shit. OH SHIT.
lol
FWIW you might want to get one of these…
i used it for calibrating my fresh water & black tank
chinese… $17
faster than filling with “calibrated” buckets !
hmm, just found out, at night, with a flashlight, I can see the level through the tank
probably during the day with the head door closed and shades down
problem solved for now
I really did not want to cut into these fresh water tanks though...
yeah thats a reliable “non automated” 🙂 method.
(my black tanks are fabricated from Black plastic material … so that trick doesnt work 🙂
and my water tanks are fiberglass … (but have commercial ultrasonic sensor factory fit)
… st
the “non contact” sensor array that @Tony mentioned at top of thread my be your answer for black tanks..
but i dont have any experience with these type sensors
Might not have to cut into them!
inspection port, I guess?
those are “standard” ports … eg for use with a float or lever style sensor …
its a “standard”? sized hole and screw pattern
man, I did not want to have to run wires...
well you need some wires .. for power, even with a wireless sensor
I have power there
.. and remember the golden rule… when you run wires.
pull thru more than you need!
have you tried to remove that “port” … im guessing its just a “blank” …
I have pulled extra through every time!
so have i .. and always run out!
I can probably use a Shelly UNI with a good old fatioed level sensor
I just pulled some line through
that is topof water tank?
yes
good.. by eye - that “port” looks around the size that might work…wiyhout further cutting
the zigbee ultrasonic sensor needs a “hole” of minimum 55mm (so the two sensors are not covered)
stick a ruler across that port (better still take it out) and see whats there
fyi 🙂 Im sitting here …. calm seas, about to have a cold beer …
https://sailing-whitsundays.com/article/lonely-planet-names-whitehaven-beach-the-number-one-beach-in-the-world-for-2025
Yeah. It might fit.
I am at my home dock, with a glass of wine, about to hit the hey
lonely planet .. ranked this beach #1 in the world 2025.. feeling very lucky to be here
.. working on another blog post for the signalk site …
these look interesting… im going to get a couple and expirement …
could be a inexpensive DIY methoid for side mounted (no holes required) tank sensors
for a couple of bucks each … you could mount an array of say 5 on the tank side (sika them onto tank)
or a different technology (“inductive”)
im going to try both ..
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