Internet enabling a coffee machine As a homage to RFC2324 we decided that we'd take a common coffee machine, enhance it a little and connect it to a WebBrick 6.1. Here's how we went about the task

Internet Enabled Coffee Machine

On April the 1st 1998 Larry Masinter published RFC2324, which set out in a humorous way how coffee machines of the future could be connected to the Internet.

Since then, white goods manufacturers have not taken up the challenge. We believe differently, after all the Internet is the biggest, most open and most reliable interfacing bus in the world.

First find a coffee maker

Since we are definitely going to invalidate the warranty, we chose to buy a machine from Ebay. we call it our Ebay BIATCH (Build, Integration and Test Coffee Hardware) We chose a Krups XN2005 on the basis that it was only 70 UK Pounds. The other deciding factor is that it has push button controls that are easy to intercept using opto isolators.

Taking the machine apart

Safety Note: The XN2005 is a double insulated machine. On the inside it has a very simple implementation of a 5V power supply which is DIRECTLY dervived from the MAINS Voltage. DO NOT attempt this modification if you are not qualified or don't understand precisely what you are doing.

Our first real issue is that these days white goods are made so cheap that no-one ever believe they will be repaired. So we're beyond security fixings and onto sheared off bolt heads. However a little gentle persausion with a 3mm drill and we had the sides of the machine off. There are four heads at the bottom to be drilled and two underneath the drip tray.

Once the bottom is removed, the sides simply unclip. With the bottom and sides removed access to the POWER and SERVE push buttons is easy.

Operation

Having won our Ebay BIATCH (Build-Installation-and-Test-Coffee-Hardware)we set about recording how it worked before modification here is the State Diagram that we derived:

Interfacing

The goal of our implementation was to make the machine useable in both standalone and Internet connected modes. This means breaking into the push buttons and interfacing with the status LED. However the PCB within the machine floats at MAINS voltages. This is a potentially dangerous situation

Therefore one of the prime interfacing tasks is to create a totally electrically isolated inteface. We achieve this using opto isolators. please consider the diagram here:

Note that we built the small interface circuit on veroboard with the optoisolators mounted in opposite directions. This is so that we create a clear Machine Side and WebBrick Side Here is a photo of the board

Next we used epoxy resin to bond the temperature sensor to the heating vessel at the bottom of the machine. You could use Araldite, but it should be the 2014 version, not Araldite Precision, which is the 2011 version. this is important because 2011 has lower grip at higher temperatures, the 2014 version is available from Farnell and RS.

Final Testing

Just before boxing the machine up, we made some final interfacing tests. The most important test is isolation where we checked that the optoisolators were indeed correctly connected and that there would be no electrical connection between the WebBrick and the coffee machine.

The next tests are operational, we used a 9V battery to connect to the WebBrick interfaces to prove that each worked. i.e. the system went ON and OFF and that coffee served. We then checked that the monitoring optoisolators could see when the buttons on the machine were pressed. From here it was simple case of connecting to the WebBrick

Enjoying Internet Coffee!

Configuring the WebBrick was as always a pretty straightforward task, here's a screen shot of the WebBrick status page:

Sneak preview of the HGA

If you've seen us at the Smarthome and Cedia shows you know that we've been working on our Home Gateway Appliance. At the moment we're really working on the look and feel through style sheets. Anyway here's what the current incarnation looks like for our coffee machine interface.

Benefits

The original Krups XN2005 machine has a simple button for coffee serve, whilst the button is pressed coffee will be served. With the WebBrick accurate timing of the coffee serve can be made. Therefore the cup can be placed, the web button pressed and hey presto - precision coffee!

Scheduling, through the WebBrick we can organise when the coffee machine is on and conversly when it gets switched off. This of course is a useful contribution to energy saving!

By preloading the cartridge before you go to bed, its a simple matter to organise your coffee in the morning either from your bedside or as a morning wake-up call!

Regrets

These days it really is busy here. Modifying the XN2005 was filled with fun, laughter and largesse about what we could have done. The real regret is that we didn't go the whole hog and modify a more comprehensive machine. Since doing the XN2005 we had our beady eyes on machines with carosels - the idea of doing a full implementation of RFC2324, where one can even choose the coffee type is quite compelling! So eBay here we come!