Monitoring water level in espresso machine

simonc

Hoping someone here has some ideas on this.

Is there a way to monitor the level in an espresso water reservoir tank such that you get a visual indication as it’s being used up rather a single binary notification when it’s empty.
Use case is I would rather fill sometimes when it’s at 25% and I have spare time than go to make an espresso when I’min a rush, or when have guests for the service boiler to fill when turned on and suddenly I have no water.

I have a minima if that makes a difference but happy to mod if required.

Thanks.
Simon

Cuprajake

float switch and beeper, used for aquarium filling?

JHCCoffee

What some folks do (and I am thinking about doing) is to fill a separate gallon glass bottle with espresso water (with whatever your water recipe is) and then use that to fill the water tank. Then you always have an immediately available supply of espresso water. So that when you run out of water at in inopportune moment, you don’t have to start mixing concentrate with Zero water. But you’d have to always fill from the gallon jar, and keep that jar full of fresh espresso water, or it could end up just sitting for a long time. Or alternatively keep that jug of espresso water as an emergency supply and replace its contents from time to time.

simonc

JHCCoffee yes I was thinking of being a 5l bottle of water and using that as you say. But then I have to store it. Not an issue with it being left, more just space.

PartySausage

A bit (very) geekish but I made an Arduino level indicator for my Synchronika using a Time of Flight sensor

simonc

PartySausage now this is what I’m talking about!! Do you have details.
I have used esp boards and rPis before so this should be doable.

I’ve actually got a mk1 minima with the weight sensor underneath the tank so was also wondering about using that.

ooglewoogle

PartySausage

That’s ridiculous. I love it. 😄👍

simonc

PartySausage I see a few related ideas using ToF sensors mounted on top of tank so get the idea but love the screen you have too so if you have code to share and parts list that would be amazing.

How is yours powered? Do you use the Synchronika‘s power?

PartySausage

simonc now this is what I’m talking about!! Do you have details.

Sure no problem, These are the parts I used:
https://www.amazon.co.uk/gp/product/B07VJ87PZC/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
https://www.amazon.co.uk/gp/product/B07BDFXFRK/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
https://www.amazon.co.uk/gp/product/B081MSKJJX/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
https://www.amazon.co.uk/gp/product/B072BMYZ18/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
https://www.amazon.co.uk/gp/product/B08C2N6R4X/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

The Arduino is connected to a Mini USB Bulkhead switch that’s mounted underneath the Sync & connects to a USB output on my power strip then routes inside the machine to the Nano
https://www.amazon.co.uk/gp/product/B08DQZY834/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

The mount for the display is a homemade special to fit round the finger hole in the lid of the Sync that the cables pass through

There will be some fiddling about to do as the tank level is mapped to the output of the level sensor for my machine.
It’s not quite a linear output at the upper & lower ends of the range due to the shape of the tank, signal reflection/absorption & there’s not much distance between the ToF sensor & the top of the tank with the ToF sensor used not being very accurate at a really close range.
There is a more recent ToF sensor, which is more accurate at close range, but that wasn’t available when I made mine & it uses a different & more complex library, which I’m not sure will fit in the limited memory of a Nano .
I’ve compensated for these foibles with a couple of fiddle factors (err constants) that offset the level value at the extremes of the range & it’s pretty close overall. All the values are declared constants to make things easier to tweak

The code is in the linked zip file, there’s a couple of 3rd party libraries that were used & also a customised font file I made to display a couple of non standard symbol that goes into the fonts folder of the standard Arduino graphics library
https://drive.google.com/file/d/1JXKKerG4w2hbGK5jN6TWfBt891TEvXwU/view?usp=sharing

As well as the level there’s a few bells & whistles like:
-Start-up graphic while the level sensor first calibrates
-Tank Open/Closed/Filled detection
-Low Level & Empty Tank messages.
-Periodic reset & calibration of the level sensor (Sometimes the heat of the machine can affect the readings & I didn’t add any temperature compensation
-Runtime indication & recovery from I2C bus lockups.

All a result of having a little bit of time on my hands due to a much publicised pandemic & no job.

The code attached has some debugging/monitoring code in it that writes to the Arduino Serial Monitor window if it’s connected to a PC at runtime. This can be removed to save some memory if needed but not necessary as it won’t impact on the normal operation

simonc

PartySausage cheers. The code / calibration should be fine, my challenge is getting the cables into the body of the minima, mounting the board somewhere and how to attach the ToF sensor to the lid of the tank. It looks like yours is all inside and presumably well away from either boiler.
Oh and how to neatly mount the display!

simonc

PartySausage

I’ve got it running now on a dev breadboard and not having soldered anything yet as need to work out fixing locations etc but it works!!!

Next step to work out how to attach to the plastic lid of the Minima tank and then work out a case for the display.

simonc

It looks like you might have a nicer lid to use than is on the Minima. I’m thinking that as I have an unused weighing device in my mk1 Minima I could use that to obtain weight using a I2C breakout that measures output from a load cell and then using same display etc

@DavecUK I don’t suppose you have insight into exactly how the spring weight sensor on the original minimas worked? I’ve disconnected mine and am using the in tank float sensor now but interested if I can still read output from it. I’m assuming it’s a simple load cell and from memory think it was just 2 wire connection?

Found the posts where I replaced and you mention a micro switch. Was the spring sensor under the plastic tank a micro switch that was on/off for water level, ie binary, or a weight load sensor with variable output based on weight.

PartySausage

simonc That’s great news good to hear it’s working for you. Look forward to seeing the finished product in action

simonc

PartySausage cheers. I’m looking at various case / bezel options on Etsy so decide how to mount. There are a few bezel options for the 0.91 screen but with open backs.
I’m having a look to see if a different display could give a better off the shelf finished product as I can’t make a case.

JonWoo187

Call me crazy/old school, but I do have quite an effective/ingenious solution for checking water reservoir level… I remove the lid and take a peep, bwahaha… Actually the tank gets topped off every single day and just have no clue why some seem like it’s such a chore with any machine. With the Cremina I once had I’d even dump the boiler empty each morning and refill to about 94.25% as I never totally trusted the sight glass.

Yes I get that some machine designs/location make checking the tank level a bit more annoying, but this sort of thing should be top priority with any machine regardless.

PartySausage

JonWoo187 The problem I have is the machine is under a very low cupboard so I have to move it to lift the lid & check the level. This meant I only have to move the machine every few days to fill the tank

simonc

PartySausage exactly. I have to pull my machine out to check the water too. Which means emptying the drip tray which is not something I should be expected to do every day.
I make up water in batches and so can’t just top up every day in small increments.
I certainly don’t have time in my day to be enjoying the boiler every day, just because…
There are times the 3 mins it takes to make an espresso is 2 mins too long and that’s with it being always on. The espresso would be a long black of I could wait for the steam boiler to heat.