The first prototype ZonCoffee v3 boards have arrived and are nearly up and running. I’m currently porting the code over to Arduino 1.0, as this board uses the Arduino Leonardo bootloader. Read on past the break for more info on the new board.

v3 Features:

• 6-Pin AUX port allows use of parallel LCD or custom expansion
• Supports SparkFun serial LCD
• USB port emulates virtual serial port for logging and loading new firmware
• All ports broken out to screw terminals
• Power via USB or external independent power source
• MAX6675-compatible footprint (also supports Maxim-IC’s newer chips)
• 6-Pin ICSP header for flashing custom bootloaders
• Main power and USB power LED indicators

This PCB includes connectors for external power, a SparkFun serial LCD, a pusbutton encoder, a thermocouple probe, a solid-state relay, and an auxiliary port. The auxiliary port pins are all connected to the ADC, allowing additional analog or digital IO for expansion. Note that the logo is silkscreened backwards, which is the only (thankfully superficial!) problem I have encountered with my board so far.

The PCB is populated with an ATMEGA32u4, an 8-bit Automotive-grade microcontroller from Atmel that features a USB interface as well as USART and SPI. This board takes advantage of USART for the SparkFun serial LCD, SPI for interfacing with the MAX6675 thermocouple interface chip, and USB for logging and updating firmware with a computer.  All parts on the PCB aside from headers are surface-mount, allowing a very compact design. For permanent installation, screw terminals can be depopulated and wires soldered directly to the board (except for the thermocouple leads, which cannot be soldered).

I have fully populated and tested two of these PCBs so far, and everything is completely functional. There are still a few software quirks from porting my original code to Arduino 1.0, but the boards themselves are fully functional. After a bit of tweaking with the encoder library and creating a drop-in library for attaching a HD44780 LCD to the auxiliary port, this design should be completely usable. I have one board up and running on my espresso machine for both use and development, and I also have a board attached to my roaster (modified Poppery I) that I will be using to experiment with ramping the setpoint for temperature-controlled coffee roasting.

Want to get one?

I’m planning on making a small beta run of boards in the coming months. Drop me an email or a comment below if you’re interested. I haven’t priced the beta boards out yet, but they will be available at a reduced price as long as you’re willing to provide a bit of feedback on the system.

The ZonCoffee espresso PID controller board has been fabbed!

The silkscreen on the board was a bit messed up; both the names layer and my text layers were screened on the board. Nevertheless, the board appears to be very well-manufactured, and I will have a board populated for testing in the near future. The EAGLE brd file and other information will be posted as I have time.

The Eagle schematic for ZonCoffee is included after the break. Note that this schematic still has a few quirks, but it should be accurate to the best of my knowledge. I will post the Eagle project once the design is finalized.

• ZonCoffee Eagle Schematic (Full-Size) [png]
• ZonCoffee Arduino sketch & software info

Prototype using a standard Arduino

• Piezo Buzzer (optional)
• Solid-State Relay- cheap on ($6, ebay)
• Rotary Encoder with Pushbotton (~$1.50, mouser)
• MAX6675- (free sample, maxim. This is an SO package, soldering will be tough)
• Thermocouple – ($3, ebay)
• Serial LCD – ($25, sparkfun)
• Screw Shield – ($14, sparkfun). Optional, but this will make your life much easier.

Permanent project without Arduino

• Arduino Permanent Install Project ($2, mouser)
• Mega328 with bootloader ($5.50, sparkfun)
• Rotary Encoder with Pushbotton (~$1.50, mouser)
• Solid-state relay – cheap on ebay ($6)
• Thermocouple – cheap on ebay ($3)
• MAX6675 – free sample (note that it is SOIC)
• You will need an Arduino or FTDI cable to program your ATMega328
• Additional components may be needed that are not listed here, such as screw terminals for wires, perf board, etc. Be creative.

I’m looking at ways to make this project cheaper, and I think I will add support for additional display types to the ZonCoffee sketch. A cheap 4-digit LED display could be used, and would be much cheaper than the $25 sparkfun display (although more of a hassle to wire, and less flexible with data displayed).

Drop a comment if you have any questions, recommendations, or if you know any sources for cheaper parts!

Skip to Downloads

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)

A few people have asked some questions about the EC155 tamper size, replacement frothing wands, etc. I’ll keep updating this page with answers to common questions.

Tamper Size

The EC155 uses a 52mm tamper (about 2 inches), and the guys over at coffeegeek recommend the RSVP Terry’s Tamper, which weighs in at a mere $6.95. If you’re looking for something a bit nicer, check out Coffee Compliments’ aluminum tamper ($17). They also offer all of their other tampers in the 52mm size, although they are all upwards of $17.

Frothing Wand

I’ve been looking around for a suitable replacement tip and/or wand for the EC155, and I’ve stumbled on a decent solution (thanks to people in this thread). Head over to your local hardware store or Home Depot and purchase a M6 x 1.0 acorn nut (stainless steel). Drill a 1/16″ hole in the tip, I drilled from the inside of the nut using a drill press and some 3-in-one. After drilling the hole, get a larger bit and drill from the other side  to remove burrs. Be sure to wash thoroughly before use! The tip seems to work quite well, although I think a smaller hole could improve performance.

Feel free to leave a comment if you’ve found a tip or wand that fits. For more information, check out this thread on coffeegeek.

Frothing Pitcher

I’ve found that a 12oz pitcher seems to work best size-wise with the EC155. The 12oz pitcher is also short enough to allow milk frothing with an acorn nut tip, without a steam wand extension. This pitcher (~$14)  is similar to the one I use. There are also cheaper options, but it’s nice to have a sturdy pitcher with a spout.

You can also get a cheap ($10) or more expensive ($14) frothing thermometer, or you can just use a cheap meat thermometer (which works well, although it won’t clip on your pitcher nicely).

Baskets

I’ve been unable to find much information about usable baskets for the EC155, but some people have had luck with some of the baskets listed below.

• Delonghi 606348 [amazon] – Fits, but results aren’t great (see androidmert’s comment)
• Delonghi 607706 [ereplacementparts] – Fits, but is quite large
• Krups MS-090716 [hard to find] – Fits

Portafilter/Basket Dimensions

I made the following measurements with digital calipers, so they should be fairly accurate:

• Portafilter inner diameter: 54.6mm at top, narrows to 51.2mm at bottom
• Stock double basket
  • Outer diameter: 54.0mm at widest point, narrowing to 49.0mm
  • Inner diameter: 52.8mm

Shot Glasses/Carafes

Since the EC155 has very little clearance under the portafilter, you can’t pull shots into a mug (unless you remove the drip tray, which is quite awkward). These double-walled thermo-glasses work very well, but any vessel shorter than the 2″ will work just fine.

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.