Gaggia Classic Pro Elegant Hack Stage 1 - Cabling

Power and Switch Wiring

WARNING!  You are dealing with 120V electricity when connecting the 5V power supply to the Gaggia power switch.   The connection to the Steam switch is also 120V.   Be very careful when connecting these and please take all precautions.  (Unplug the Gaggia power cable before working on the 120V wiring).   Build at your own risk!!!

First we discuss how to power the Arduino Nano.   There are a number of ways to power Arduino.  (USB power, Vin power, and 5V directly).  Since I needed a power supplies for steam switch detection for the build, I opted to purchase a set of 5V power supplies that can do both jobs.   The first power Supply is to provide power to the Arduino.   Please see diagram below.   




5V Power Supply #1

This is used to power the Arduino and it gets the power from the power switch from the Gaggia Classic.   Use the 22 gauge wire from Amazon.   We are only using 5V*2A = 10W of power.   Over 120V, it is roughly 0.08A of power so not a lot of current will be going from the power switch to the Arduino power supply.   You should connect the L (I am using red cable) to the line side of the Gaggia power switch (marked by white).   N is for neutral (I am using black cable), the neutral side of the Gaggia power switch should be marked in brown.   (See picture below)


Used two Red Peggy back connector show in the next picture from the Amazon connector kit.  


I am using red cable for LINE (L) and black cable for neutral (N).  Unplug the bottom row of the Gaggia power switch (white cable on the left and brown cable on the right.   Insert the piggy back connector as follows,  (Again reference the first picture above)
  • Left Piggy connector has the Gaggia white cable and power supply red (L) cable connected together and inserted to the lower left slot.
  • Right Piggy connect has the Gaggia brown cable and power supply black (N) cabled connected together and inserted to the lower right slot.  
The +5V and the ground (-5V) of the power supply is connected directly to the Arduino.  (You can cut a wire in the appropriate Arduino prototype wire connector set that you purchased from Amazon.   Solder one end of the cut cable direct to the power supply.   Use the connector end to plug into the Arduino pins.   The +5V is directly connected to the +5v pin of the Arduino.  The ground (-5V) pin is connected to the ground pin on the Arduino.   Note, this way to power the Arduino has one drawback.  You can NOT plugin the USB connector and power the 5V from Gaggia at the same time.   Whenever you are programing the Arduino via the USB, please ensure the Gaggia power is OFF.   

5V Power Supply #2 (Steam Switch Detector)

Instead of buying an expensive AC voltage detector that is compatible with Arduino, let's use the second power supply #2 as the switch detector.   When the Gaggia steam switch is in the down (steaming) position, the lower row of the steam is powered by 120V AC.   This will power the supply a 5V supply to a digital input pin on the Arduino for the software to detect it.  

Construct a red wire 22 gauge with the following connector on one end.   The other end should be soldered to the line (L) terminal of the power supply.   


The connector should be connected to the spare open connector on the Gaggia steam switch.  See picture below.   (The steam switch is on the left most switch)


The neutral (N) terminal of the power supply should be connected to power supply #1's neutral (N) line.   No need to run another line or figure out where to plug it.   Both neutral (N) terminal of the power supplies is the same.  

The +5v output of the power supply is connected to the Arduino's D6 pin.  When the steam switch is switched ON, the D6 pin will now be +5v.   This is how Arduino knows when the steam switch is ON.  The -5v (ground) pin of the power supply can be connected to any Arduino ground pins.  

Brew Switch Connection

Please see the photo above.   The brew switch is the middle switch.   Make two cables of any colors and use with the connectors from the amazon kit on one end.   Plug in the left side of the brew switch open terminal connector slot.   (Marked by red connector and white and green cable).  Connect these cables to Arduino's pin D7 and ground pin.   Since this is just a close circuit switch detector, the order how you connector the wire does not matter.  Arduino will just now when the brew switch is closed, that the D7 pin is connector to ground.  (The digital input mode for Arduino D7 pin is called INPUT_PULLUP.   Google it if you want to learn more).  Also notice that I am using of the digital output pin as ground so I don't have to solder.  In this case D2 is setup as digital output LOW.   You can read the source code to see how it is done.  

Cable Routing

Make sure of the following.
  • Ensure no cables are touching the boiler 
  • Run the cable through one fo the ventilation slot shown below.   
  • Wrap some electrical tape around the cable where it is contacting the metal case.  Will will prevent the metal cutting into the silicon cable over the years of use and pump vibration.  Better to be safe than sorry.



Congratulations!  You are done with all the Stage 1 cable connection to the Gaggia Classic Pro! 


Coming up Next - OLED connections...
 

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