dlime/gaggiuino

Intro

Gaggiuino started as an idea to improve an already capable coffee machine while keeping the machine appearance and button functionality as close as possible to the original. An important part is that no internal cables/connectors were modified; all the connections were made by creating splitters using the purchased spade connectors.

SUCCESSFUL INSTALLS:

MODEL	YEAR	VOLTAGE	PHOTOS
Gaggia Classic	2012	240v	https://bit.ly/2Xv1fiv
Gaggia Classic Pro	2019	115V	https://imgur.com/gallery/SF3zP0b

Features / Completeness

Notes:

Pressure:

It is expected your OPV has been tuned to 9bar by default.

Initial pressure tuning has been performed according to a portafilter pressure gauge. While this is better than nothing and gives nice results, it's not real PP per se as the pressure at the puck can't be directly controlled. I have started looking for a suitable (food safe) pressure transducer which will allow for a feedback loop and real time dimmer control for a real PP experience.

Regional power:

Defaults to 230V/50Hz and should be changed to the regional values for the correct work of the ACS712 sensor.

Possible future features:

Pressure transducer
- Used for a feedback loop to make real-time pressure adjustments based on puck resistance
- Possibly auto-calibration of non 9bar
Load cells
- Exploring the options of integrating some small load cells with the water tray for real time weight feedback.
Flow sensor
- Exploring the idea of introducing some water flow sensing so predefined ammounts of water can be output, this might prove to be less useful and kind of redundant with the load cells, unless it adds some benefit I don't see yet.

<< Ideas are welcome in the Issues tab >>

User Interface:

USAGE:

BOILER - sets the desired temperature at the boiler level
OFFSET - sets the offset value used to calculate the real water temperature
HPWR - sets the relay start pulse length
M.C.DIV - sets the main cycle divider(aka non brew heating beahaviour), used in conjunction with HPWR
B.C.DIV - sets the brew cycle divider
PREINFUSION - sets the preinfusion length and pressure

P-PROFILING - enables either AUTO or MAN pressure profiling mode

AUTO     - sets the profiling trend incremental or decremental (can be combined with preinfusion), some examples bellow:
MAN      - allows for manual pressure control at brew time

DESCALE - enables the descaling program, at this point there's only one default behaviour:
```
  flush - 10s x5 at 2bar
  flush - 20s x5 at 1 bar
  idle  - 5min at 0 bar
```

Pre-infusion[PI] and pressure profile[PP] usage examples:

No	BREW MODE	DESCRIPTION
1.	[PP] 9bar >> 6bar	the brew starts at 9 bars and stays at 9bar for 8 seconds then starts slowly dropping towards 6 bars,all this aims the official 30 seconds shot times, if the shot goes above 30s seconds the pressure will just remain at 6 bar untill the end of the shot.
2.	[PP] 6bar >> 9bar	same as above but viceversa.
3.	[PP] 6bar >> 6bar	the pressure stays locked at 6 bar.
4.	[PI] 8sec >> 2bar [PP] 9bar >> 5bar	preinfusion for 8 seconds at 2 bar >> pause 3 seconds (aka soaking) >> behaviour from point 1.

PROJECT REQUIREMENTS

Software requirements:

Arduino IDE

Needed to upload the code ".ino" to the arduino ROM

Libraries to add:

  Library manager:
   - Easy Nextion Library
   - MAX6675 by Adafruit

  External libraries:
   - ACS712 > https://github.com/rkoptev/ACS712-arduino
   - RBDDimmer > https://github.com/RobotDynOfficial/RBDDimmer

Nextion Editor

Only necessary if planning on editing the ".HMI" file to ammend the LCD functionality
CH340 USB Driver

USB driver so your system recognizes the Arduino clone board, let's say i have found this the hard way as apparetly the majority of cloned arduinos use a cheaper USB controller comparing to "genuino"

Hardware requirements:

The code has been designed to be plugable, meaning there is a minimal hardware configuration one can start with if certain features are not something of interest, next to the hardware component there will be anotated whether its a [BASE] or [EXT] functionality component type

Arduino Nano AT328 [BASE]
- Arduino Nano expansion board
Nextion touch screen [BASE]
MAX6675 thermocouple [BASE]
C-M4 screw K-Type thermocouple sensor [BASE]
40DA SSR Relay [BASE]
RobotDYN dimmer module - Dimmer 4A-400V [EXT]
Hall Current Sensor Module ACS712 - 20A [EXT]
Thermo-resistant cables AWG 15 ( 1m black/red ) and AWG 30 ( 1m black/red/yellow ) [BASE]
Spade connectors M/F 6.3mm
5v Power Adaptor [BASE]

I used an old mobile charger I had lying around which conveniently had a USB port for plugging the cable that came with the board, exactly like in the link above. If you're printing the housing as well skip this for the one in the housing section.

Housing:

Gaggia Classic Arduino & Touchscreen Housing

Designed by the redditor /u/LikeableBump1

Additional parts required to fully assemble housing:

5v power supply

This replaced the mobile charger that is recommended above. I still used a mobile charger with the casing removed to make it fit, but these should simplify things, and are cheap. Make sure you purchase the 5v 1500mA version.
DB15 D-SUB connectors, male and female

These are used as a disconnectable pass-through to get the data and power cables through the back of the machine case. The 3d files include custom housings for these connectors. There will need to be 2 or 3 of the vertical "slats" cut out of the cooling vents on the machine case back to make these fit. Make sure you purchase both male and female DB15 connectors.

Additional notes for 3d printed housing:

If you use the standard .tft file attached above, the UI will be upside down, due to the way the screen has to be installed in the 3d printed housing. There is an additional .tft file for those using this housing, or you can open the .hmi file in the Nextion Editor yourself and flip it.

Optional:

Heat shrink
Soldering iron

I bought it for my soldering needs, seems to do a great job. It's important to not leave it ON while not in use as the heating element will get damaged.

Schematics :

GAGGIA Classic Pro

!! WARNING !!

First and foremost please do not underestimate the danger of electricity or overestimate your ability to work around it. Only start working on your machine while it's completely disconnected from the mains power socket, also by agreeing to follow the below guide I cannot be deemed responsible for any of the damage you induce to your house appliances, yourself, your cat, friend or gold fish and it will be entirely your fault!

Assembling

First we need to understand what goes where. The schematics aren't really rocket science but for someone who's never disasembled or has no experience working with electrical circuits it might get confusing really fast so I will try to describe it as simple as possible yet limited by my vocabulary. First let's check that the setup works as expected while outside the machine so you don't have it all installed and realise just afterwards it's not reading any temperature because of a faulty component or the relay doesn't switch between the ON/OFF modes.

Note 1 - no permanent connections are needed during testing so no soldering needed for now.

Note 2 - the 5v/GND Arduino board pins will be shared between all the connected devices.

BASE FUNCTIONALITY

The first step will be connecting the MAX6675 module to the arduino board using the pins defined in the code. You can find them defined at the top of the .ino file.

MAX6675 Arduino

VCC 5v

GND GND

SCK D6

SO D4

CS D5
Connect the relay. For now only connect the circuit controlling ports to check whether the relay LED indicates the power states.

Relay Arduino

4 GND

3 D8

Relay ports [1] and [2] are the high voltage circuit breaker
Plug the arduino board in using the mini USB cable that came with it and upload the code to the arduino board.

Note: uploading won't work with the LCD connected
Nextion LCD wiring

Nextion Arduino

TX RX

RX TX

VCC 5v

GND GND

MAX6675	Arduino
VCC	5v
GND	GND
SCK	D6
SO	D4
CS	D5

Relay	Arduino
4	GND
3	D8

Nextion	Arduino
TX	RX
RX	TX
VCC	5v
GND	GND

Uploading the LCD ROM code

Method 1

 Just copy the *.tft file on a FAT32 formatted microSD card and upload onthe LCD panel using the onboard card reader

Method2

 Open the .HMI file using Nextion Editor and using the File menu upload it on a microSD card

Note: card needs to be FAT32 formatted

After the upload is finished get the card out and power cycle the LCD.
You should see temp readings on your screen if everything went according to plan.

Don't forget to test the thermocouple/relay combo operation, apply some heat to the thermocouple end and see whether the relay led operates in HIGH/LOW modes

At this point if all the above works as expected you're ready to install it all inside the machine. For this we'll need to prepare some splitters that we'll use to connect to the Gaggia internals without introducing any permanent modifications so in the event of a desire to revert to stock it's a few disconnects away!

EXTENDED FUNCTIONALITY

Adding the ACS712 hall current sensor is quite straight forward

ACS712 Arduino

VCC 5v

GND GND

OUT A0

The high voltage circuit control ports will act as a passthrough for the front panel brew button positive wire
Adding the dimmer

Dimmer Arduino

VCC 5v

GND GND

Z-C D2

PSM D9

Dimmer high voltage circuit control ports will act as a passthrough for the pump positive circuit wire

ACS712	Arduino
VCC	5v
GND	GND
OUT	A0

Dimmer	Arduino
VCC	5v
GND	GND
Z-C	D2
PSM	D9

Now I won't be explaining every single detail, as always with such projects common sense should be applied at all times, it's expected people doing such sort of modifications will have some basic understanding.

AGAIN!!! Triple check your machine is disconnected from any power sources, even better just pull the power cable out of it!

BASE FUNCTIONALITY

Take off the top cover by unscrewing the 2 top screws. You should be able to see something similar to the below image minus the SSR relay:

Prepare 2 splitters like in the below image using the AWG15 cable, be sure one splitter to be black(negative) and one red(positive)

Be sure to mark your top left power connector so you don't mix them up ( even though it's not that hard to understand which one is which)

Disconnect all 3 of them as you'll use the midlle and bottom ones for power sharing.

The hardest part will be now in my opinion as you'll have to unscrew the bottom boiler stock thermostat and screw back in the new thermocoule. Be sure to apply some thermal paste on the thermocouple threads. (Just a teeny tiny bit.)

Prepare 2 cables you'll use to connect the cables disconnected from the thermostat to the port 1 and 2 of the SSR relay. Use the red cable for that. They shouldn't be too long, about 10cm will suffice, one end should be crimpled with a male spade connector and the loose end screwed to the relay and attach the relay to the machine case itself, I have no clue what screw size I used as i have just matched one by trial and error lol, but be sure to apply some thermal paste to the SSR backplate that will make contact with the metal case of the machine.

So you end up having them connected like this:

Prepare 2 more 10cm cables( also colour coded accordingly) which should be crimpled with M/F spade connectors at each end, the female end will go in Gaggia's front panel and the male end will go to the female end of the previously prepared (2) splitters, as in the below image:

Connect the front panel cables to any of the free male ends of the splitters as well, black one for the negative cable and red for the positive one (on my machine the positive is having 2 cables crimped together).
To power the Arduino system I have used an old 5v mobile charger which I'm sure all of us have laying around. Just solder 2 cables to the 2 ends of the charger and for the other ends use 2 F spade connectors, after which plug them to the remaining 2 splitter (2) ends.

Now you're ready to connect everything to the arduino like you did it when testing everything, one piece of advice would be to solder all the Arduino connected cables as during the machine operation there is quite a bit of vibration and that can introduce all sorts of noise/frequent disconnects to certain pins which will lead to unexplained behaviours.

EXTENDED FUNCTIONALITY

While installing the ACS712 Hall current sensor please note in the photo below the way the sensor faces the camera and how the cable passthrough is done with the cable originally connected to the middle slot front panel brew button (1). It's a short cable connecting the brew button with the steam button, we leave it connected to the steam button but the end which was connected to the middle slot of the brew button connects now to the top port of the ACS712 board (1) and then the exit (2) port of the ACS712 board feeds a cable to the original front panel brew button position.

It is important to connect the cables properly as the sensor has a polarity and when incorrectly connected outputs a negative value!

Installing the RobotDYN dimmer module.

Once installed tests can be done to verify the dimmer output is the expected one, this will require having either a portafilter gauge or an internally mounted gauge.

dlime / gaggiuino