Gaggiuino -part 5 - wiring

This is part five of my Gaggiuino project.

Basically this adds a microcontroller to a relatively cheap coffee machine.

The earlier parts are here:

   Part 1 Gaggiuino Build Log with Workflow intro

   Part 2 Gaggiuino V3 - Build Log Notes - switches, PCB

   Part 3 Gaggiunio mod - The original Classic Pro - How it works

   Part 4 Gaggiuino - boot first time 

At this point I'm just breaking down the wiring and reading the schematic.

I often find I absorb info better if I write things down. Thus this blog.

And hopefully, it will help someone else doing this awesome project.

I am not part of the Gaggiuino development team so there may be mistakes here.

Do let me know if you find any. 

I have a 240 V Gaggia classic pro evo

And I'm using an official PCB from Peak in HK

I bought the kit with lots of parts to get this job done (hopefully with little fuss).

Though, you will need more cables, basic soldering skills & some patience.

Peak Coffee:

https://www.peakcoffee.cc/product/gaggiuino-v3-kit-set-gaggia-classic-pro/

The official project page is here:

https://gaggiuino.github.io/#/?id=home

The discord page is also useful:

https://gaggiuino.github.io/#/community/community-media

There are two important pics you need to digest to wire things up.

The first time I saw the pic below I was at a loss to see where things started or ended.

I'm familiar with electronics schematics, but the mix with hardware is new for me.

But its actually not too bad once you study it, compare to the schemo and work out what the labels mean.

Remember you are playing around with high voltage (240VAC), low voltage DC and hot pressurised water.

So be very careful.

If you've got a different machine, things will be a bit different, but hopefully not by too much.

The code goes something like this :

G = ground

3WV = 3 way valve

the 3 way valve has 3 terminals.

3WV N

3WV L

3WV G

Socket N = 240V power Neutral socket

Socket G = 240V power Ground socket

Socket L = 240V power Line socket

The brass 57 solenoid has 3 flat spade connectors

G = Gnd

L = Line

N (blue) = neutral

keep in mind that there is a difference between high voltage & low voltage cables

(HV use Crimped 6.3mm Terminal Connectors, 30-50cm AWG 22 cables )

Here is the schematic. Try to unite this in your mind with the pic above.

.......................................

I think I'll start with the 240v socket
(these are the pink boxes).

These connect to Neutral, Line & Gnd.

Socket N = 240V power neutral socket (blue in the schematic)

Socket G = 240 power ground socket

Socket L = 240 line socket

These need to be the thickest gauge wire as they are carrying the highest current

-------------------------------------------------------

The Solenoid

The brass 57 solenoid has 3 flat spade connectors

Its also know as the 3 way valve in the schematic.

3WV = 3 way valve

the 3 way valve has 3 terminals.

3WV N = neutral (blue)

3WV L = line (yellow)

3WV G = gnd

---------------------------------------------------------------------------------------------------------------

these yellow boxed ends connect with the PCB

3-out ( to 3WV L)

P-out (to Pump L)

L-in (to the SSR)

N-in (to the pump fuse, pump N, etc)

all connect the PCB to the  outside world.

---------------------------------------------------------------------------------------------------------------

The vibratory pump

It looks like it has just 2 terminals (Pump Fuse to Pump N 

& Pump L).

These connect to N  & P on the PCB.

---------------------------------------------

grounding wires

All green wires.....   start at the 240V power socket (socket G) on the right

and work left  (frame - 3 way valve - boiler ) to end at the cup warming plate on the extreme left.

-----------------

The SSR (Solid state relay)

A solid state relay (SSR) is an electronic switching device that switches on or off when an external voltage (AC or DC) is applied across its control terminals. They serve the same function as an electromechanical relay, but solid-state electronics contain no moving parts and have a longer operational lifetime.

It has two sides.

A high voltage AC side and a low voltage DC side.

The AC side connects to the coffee heating elements. 

The DC side connects to the PCB.

It basically translates between the two.

Both sides are isolated (even though they can communicate with each other) using LEDs and phototransistors.

What the SSR does is listen to commands from the microcontroller. 

If the microcontroller sends low voltage digital info to the SSR (say

to heat up the water), the SSR will carry out the command on the high voltage AC end.

It looks like the left AC out from the SSR 

connects to the thermofuse, 

or the resettable fuse 

& one heating element

I don't think you connect it to both.

+ Gaggia Classic Evo Pro - Modding with arduino - Gaggiuino

   Part 1 Gaggiuino Build Log with Workflow intro

   Part 2 Gaggiuino V3 - Build Log Notes - switches, PCB

   Part 3 Gaggiunio mod - The original Classic Pro - How it works

   Part 4 Gaggiuino - boot first time 

   Part 6 Gaggiuino boiler & pump removal