DIY coffee machine

Projects General Guidance
1

Hi,
I'm trying to build my own coffee machine. As I'm a computer science student my knowledge of electrical engineering / components is very limited.

I want to start with the water supply first and designed a schematic in order to control the water pump and heat element. I was planning to use a nodemcu microcontroller to control the whole thing. i use the temperature controller to know how hot the heating block is and to turn it off. when it reaches 70°C i get an input signal at D3 pin of the nodemcu and turn off the relais.

in the attachment i put the schematic i designed. of course the 5v relais are connected to the 5v power supply. from another project i know that the 3,3v output from the nodemcu is enough to trigger the 5v relais.

i would be very glad if someone could give me an opinion/improvements about this.

im using the following parts:

water pump:
Ulka Model EFM Type EP5FMGW/SP 230V 50Hz 48W 2/1min. Cl155 Tf35°

heater:
https://www.ebay.de/itm/Heizelement-Durchlauferhitzer-Kaffeemaschine-ORIGINAL-Philips-Saeco-421944028841-/123033085634

nodemcu:

12V AC/DC Converter:

5V relais:

temperatur controller (W1209):

stepdown module:

Gescannte Dokumente.pdf (568 KB)

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824×608 596 KB

3

You might want to rework this a bit if you are going to use it in the USA. Your heater requires 1900 watts, that is more than a standard 15 Amp branch circuit can supply. You will need at least a 20 Amp outlet for this. Your schematic shows 220V, that would work and is common in many non US countries. Other then that is looks good to me!

4

That's a 230VAC heater, about 8A.

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