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Features

• Displays set point and current temperature information on LCD
• Rotary encoder adjusts temperature targets without a computer
• Intuitive serial interface, compatible with the BBBC grapher
• Steam and extraction modes with separate temperature targets
• Simple configuration in “Options.h”

Supported Hardware (Version .2)

• 1 rotary encoder with pushbutton (software debounced)
• 1 SparkFun serial LCD
• 1 piezo buzzer (beeps when preheated)
• 1 zero-crossing solid-state relay
• 1 MAX6675 thermocouple chip (free samples available from Maxim IC)
• Additional Details

Average Hardware Cost

The entire project can be built for around $40 (not including an Arduino) assuming you acquire a free sample of the MAX6675 chip. ZonCoffee (as of .2) requires an ATMega168 or higher. The sketch is around 14kB compiled.

Plans for future versions:

• Support for additional thermocouple chips (have defines in options.h to choose which to compile)
• Support for additional display types. Possibly abstract display output functions.
• “No LCD” mode (use LED for indication).
• Release version tailored to PID for popper coffee roasting

Download

• ZonCoffee .2 [zip]
• ZonCoffee .2 [gz]

This is a build log of my PID modification to my DeLonghi EC155 espresso machine. Currently, the machine uses an Arduino to drive a solid-state relay controlling the heating coil. The Arduino displays mode and temperature on a serial lcd, and also dumps status information over the serial port.

Update 1: I’ve ordered parts for a permanent install on protoboard, after I finish the install, I’ll update this post with build instructions and details. I will also provide a link to a mouser project where you can order most of the parts in one place.

Update 3: Everything is assembled and functional, and I made an aluminum case thing for the LCD and rotary encoder. Photos to come soon. (8/25/10)

Update 4: ZonCoffee .2 is released! See the release page to download the sketch and to see additional hardware information. (1/4/11)

This post is one of a series of posts regarding mods I have done to my EC155

Required Parts:

• Thermocouple ($2, ebay)
• MAX6675 (maxim-ic) (now sold by sparkfun! 7/17/10)
• Arduino-bootloaded AVR  of some sort ($30, sparkfun)
• Solid-State Relay 25A+ ($7, ebay)
• Switch (any type will do)

Optional Parts:

• Serial LCD ($25, sparkfun)
• OSRAM SLR/SLG/SLO 2206 LED Display (driver coming to ZonCoffee soon, will require shift register)
• Screw Shield ($10, sparkfun)
• Rotary Encoder

My build is currently on a Arduino board with a screw shield, but I’m planning on making a PCB soon. I’ll update this page with links where you can purchase the PCB (probably through batchPCB) in the near future.

Software:

• Modified BBCC code (arduino sketch)
• Modified MAX6675 library
• BBCC plotter (processing sketch) [link]

Construction:

1. Installing the SSR and Thermocouple (coming soon)
2. Connecting the electronics (coming soon)
3. Editing and uploading the software (coming soon)
4. Calibrating the thermocouple (coming soon)

The DeLonghi EC155 is a fairly well-built consumer pump espresso machine. It ships with a pressurized portafilter of a non-standard diameter, so finding a non-pressurized replacement is challenging. Instead of purchasing a new portafilter, depressurizing the EC-155′s portafilter is extremely easy.

This post is one of a series of posts regarding mods I have done to my EC155

Non-permanent method:

1. Unscrew the plastic retaining knob on the bottom of the pressurized filter assembly

2. Push the plastic nozzle to remove the filter assembly

3. Remove the filter and plastic piece from the gasket

4. Re-assemble the gasket and filter, leaving out the black plastic pressurizer

5. Place the gasket and filter assembly back in the filter holder

6. Note that oils and grounds can become trapped in the filter holder, so be sure to wash it often. You’re done!

Permanent Method:

1.Disassemble the portafilter down to the plastic piece with the pressurized nozzle

2. Using a pair of needle-nose pliers or a flathead screwdriver, pry off the plastic ring holding the pressurization nozzle together and remove the pin and spring.

Warning: the spring might fly out and hit you. Don’t be pointing it at your face.

3. Re-assemble and use as normal. Save the plunger, plastic ring, and spring in case you want to repressurize it later.