Intro and Costs:

I have bought a Delonghi Icona coffee machine, however I purchased it without realising that it is a basic manual machine.

Considering the warm up time (1:45 approx.) plus the brewing time (40sec) it is quite a bit of wait-around in the kitchen in the morning, when I am only about getting the first coffee down. Furthermore it really needs an eye kept on it otherwise the thing will simply overflow until the water runs out / something brakes / Armageddon hits the earth.

The hardware is simple and I consider that it was cheap as well, namely:

Arduino Nano - US$3.64

4 channel Relay - US$3.99

Neutrik USB socket - £5.99

Push Buttons - £2.97 (+ £2.07 postage)

USB cable - £1.63

Wires + Labour

I also had to invest into other hardware i.e. solderer/flux/soldering iron, however these more like capital costs rather than strictly related to the project.

The biggest work was to dismantle the unit into parts and solder the wires to the existing switches. These had to be fitted so that the manual switches can still be used (in case something goes wrong with the Nano). Furthermore, extra care had to be also taken as these wires carry 230V AC so there is no place for uninsulated loose ends.

The easier half of the work was to link the buttons and the USB socket to the Arduino. It was easier since it can be tested on a bench-top in advance and works with only 5V DC - so it is not the risky part of the electrics.

Functions:

The system has a usb socket through which the Nano receives power. Then the Nano powers the 4-channel relay.

The three buttons are for: Short Coffee, Long Coffee and Reset. The latter is to stop the machine in case we fear of overflow or just want a bit more 'mud-like' coffee. Either pressing the first two buttons switches the heater on in the coffee machine (red light comes on in video) and waits for 1min 45 sec (this is the longest warm up I timed). Then depending on which button we pressed the Nano switches the pump on and the machine brews a short or a long coffee.

The program is a simple loop with two if statements. Both of which checks for either of the buttons being pressed and commences with the program described above.

Conclusions:

It was extremely important for me to have the finished product look like if it came out of a factory. Although, I might have not achieved this - I am still pleased to say that the appearance of the unit looks more industrial/professional than I initially thought it was going to be. I am definitely happy that there is no lose wires sticking out randomly making the machine look almost like it was designed to be like this.

The biggest risk in the project is working with 230AC. Wiring of mains supply should only be carried out by competent personnel to avoid risk of electrocution!