Custom and Robust Water Level Indicator for Coffee Machine That Couldn't Be Simpler

Today, despite their price, most expresso coffee machines do not have any water level indicator visible from the front of the machine.

Not only annoying for a coffee lover like me, running out of water while the machine is running can cause long-term damages for the pump and the internal resistor which continue to heat up even without a water supply.

I propose here a robust, fully mechanical water level indicator, whose graduations will be adapted with your own size of coffee cup.

Supplies :

-Wood piece as floatter, aprox 4 x 4 x 2cm. A plastics or polystirene block would be even more efficient.

-20cm wood cylinder, 4mm diam.

-15cm transparent pipe. The wood cylinder must easily slide inside the pipe.

Tools :

-Electric drill

-2 x drill bit (4mm and 6mm. The first one must be the same diameter as the wood cylinder, the other one slightly larger).

-Permanant marker

-Hot air gun (optional)

-Cutter or scissors

Warning :

Consider that the floatter will be in contact with drinkeable water, so use a material that is safe with food contact.

Be carreful when using an electrical drill, scissors or a cutter.

First, we will determine the position of the indicator. The objective is to drill a hole with the big pit on the top of the water reservoir.

We must pay attention to the handle movement, by locating a point where the sensor will not be hampered. So that, as shown in the picture, place the wood cylinder and the plastic tube on the top of the reservoir ant then actuate the handle to check that it does not hit the tube.

Once the point marked, drill a hole with the 6mm pit. The wood cylinder must slide easily within this hole.

Objective : Fix the float to the wood cylinder

First, drill a hole on the float, ideally with the same diameter as the cylinder. This will avoid the use of glue.
You must find a drill point where the float, once attached to the cylinder, will correctly slide up and down inside the reservoir.

Then, insert the cylinder in the hole. The two parts must not separate from each other.

We will now add a mark that will represent the current water level.

The float is currently in "empty" position. Add a mark somewhere on the cylinder, but take care that it will be visible from the front of the machine.

Then cut the cylinder just above the mark.

Now, put the transparent pipe on the cylider and check that it can slide correctly. If the pipe is not straight enought, slightly heat it with the hot air gun and remove the curves.

Then, glue the pipe to the reservoir with hot glue. Warning : the glue must stay outside and mustn't block the movement of the wood cylinder.

Fill the reservoir with your favourite cup. Add a mark on the transparent pipe between each cup.
The float probably won't move before 2 or 3 cups. It will naturaly constitute a safety margin of few cups when the "empty" mark is reached.

Last but not least, cut properly the pipe above the "full" mark and say goodbye to the inconveniances of an empty reservoir.