MooBella has put Linux to work making ice cream, in a vending machine that Wallace and Gromit would be proud of. The MooBella vending machine uses Linux 2.4 and a Red Hat filesystem to make 96 varieties of ice cream, on demand, in about 45 seconds per precisely-measured serving.

MooBella showed off its Linux-powered ice cream machine at a DEMO event in Phoenix today.

The machine has a 15-inch flat-panel LCD interface, with a touchscreen overlay that customers use to choose their flavor. The machine can be stocked with up to two “base mixes,” 12 flavor mixes, and three dry-ingredient mix-ins, for a total of 96 possible varieties.

Once the customer's selection has been made, a quantity of base mix is precisely measured and pumped, aerated, flavored, and sprayed onto a flat rotating surface, where it is flash frozen. The product is then scraped up by a tiny snowplow, formed into a cylinder, and dispensed into a paper cup.

Unlike soft-serve ice cream machines, MooBella creates real ice cream, the company says, in 45 seconds, to customer specifications. The machine consumes MooBella's proprietary formulas, which are packaged aseptically using “bag-in-a-box” technology that requires no refrigeration until the bags are opened.

Linux?

Where does Linux come in? VP of Engineering Jim Baxter explains, “When I began the project five years ago, it was a typical embedded project, written in C++, and very restrictive. Later, we realized that number one, the system needed to be modular; and two, we need a lot more horsepower to drive all the things we need to do. That's when Linux rose to the top. That's part of the innovation that led to this.”

What's under the hood?

The MooBella machine comprises seven modular mechanical units, including pneumatics, base refrigeration, flavor, processing, primary refrigeration, foodzone, and mixing modules. A Linux-based computer operates each module through a distributed control system based on a CANopen bus. This architecture gives the company a lot of flexibility in testing and repairing modules, Baxter says. “Each module can be tested, operated, and serviced, without being part of a full machine — as long as you have the OS running,” he said.

The MooBella is currently based on a commodity, off-the-shelf PC motherboard, although Baxter says the company is investigating more “industrial” options, noting that cafeterias can present adverse computing environments.

For now, the MooBella is powered by an AMD 2600 processor clocked at 1.3GHz, with 512MB of RAM, and a 40GB hard drive.

I/O includes one serial bus, four USB ports, and one parallel port. Digital I/O is connected through a CAN bus add-in card.

The MooBella also has two different kinds of proprietary wireless interfaces, with a third under development. The first, designed in-house, is used in the machine's network of temperature sensors. For example, a thermocouple buried within the rotating freeze plate allows temperature control as fine as 1/10th of a degree, Baxter boasts.

The MooBella's second, satellite-based wireless interface is used to access the machine remotely by a company hired to manage inventory and machine health. This interface was provided by vending machine maintanence specialist Cantalope, which rents space on satellites for its proprietary networking equipment. Baxter says partnering with Cantalope saved MooBella from developing a lot of human interfaces that Cantalope already had. And, says Baxter, “They were looking for someone like us, who's more computer-based, to take advantage of all they can do. They've taken our source code, and added some hooks.”

Baxter also expects to add an RFID (radio frequency identification) radio to the MooBella machine, in order to automate inventory tracking. He says early designs incorporated barcode scanning, which proved cumbersome for maintenence staff.

Additionally, the MooBella has an RJ-45 port, allowing service personnel to connect to the device using crossover cables. “With a crossover and password, you can drill into the machine, download data, manipulate inventory, change the way the machine processes things, or do software upgrades in the field. If the machine is on the Internet, I can do the same things from my desk,” Baxter says.

Embedded software

MooBella's Linux implementation is based on a fairly stock 2.4-series kernel, along with a Red Hat 9.0 filesystem. The user interface is based on a Firefox 1.0 browser, allowing simple remote interface updates, and lots of customizability. Baxter explains, “The consumer interface is a set of graphics that's all Web-based. Soon, we'll be pushing graphics into the machine, to help sites such as Brandeis University promote special events.”

MooBella also created a service page for maintenance personnel, who can use USB sticks to “push in” interface updates or new graphics.

Baxter notes that the MooBella currently has no payment processing or cup handling system. But, he says those are very well-understood problems, compared to solving the complex problem of making “reliable ice cream every time.” He said, “The commerce side is a piece of cake. We've got USB, serial, parallel, and other I/O [available] to connect to cash registers and commerce devices, so we don't actually have to handle money ourselves,” he said.

Other open source software leveraged by MooBella includes the PCAN driver, a Linux driver for a Silabs cp210x USB to UART converters, a C development environment, PHP, and dash. And, notes, Baxter, MooBella makes extensive use of open source SQL databases.

Baxter said, “We have lots of databases, including a database with all the graphics information. There's a whole set of databases on all the machine components, so that if we have to substitute a different motor, we can update its characteristics in the database, and the software compensates for that component going in. There's a SQL database for sales, with date and timestamps, so we know what was sold, and when, by basemix, flavor, and mix-in. If there are any errors within the machine, there's a database for that, too.”

MooBella's most impressive database, though, has got to be its food product database, which is used to create a “process recipe” executable on the fly, for each product ordered. The executable is then run, at which point it takes control of the various modules, ultimately producing ice cream.

Baxter explains, “Each product has its own characteristics that relate to processes that need to happen in order to make the best ice cream. As a consumer, you make your selection, and machine uses a SQL database to create a process recipe for the specific combination of ingredients you select. For example, the speed of the freeze cycle may need to change, based on how long certain ingredients take to freeze. The speed of the base mix motor pump may need to change, based on the viscosity of a certain material. We have an infinite capability to add food products.”

Why Linux?

Baxter says MooBella chose Linux because of its connectivity power, and because of its open source nature. “It's a very powerful system, and there are a lot of people doing innovation in the Linux environment,” he said.

Using Linux presented two challenges, Baxter says. The first was finding drivers. “Hardware drivers are tough to find, and tough to get working,” he said. “In a lot of cases, they're just not robust enough.”

The other challenge MooBella faces is simply getting Linux installed. “For example, say we have a formatted drive, and one we need to upgrade. The process of just pushing our OS and applications onto it is a real pain,” Baxter said.

Generally, though, Baxter appears to be more than pleased with the company's choice of Linux, especially in light of what he describes as an “overwhelming” response to the product at today's Demo event. “This product has gotten further than I ever imagined, in my wildest dreams,” he said.

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