Jon Nordby

MsgFlo is a tool to build systems that span multiple processes and devices, for instance IoT sensor networks. Each device acts as a black-box component with input and output ports, mapped to MQTT message queues. One then constructs a system by binding the queues of the components together. Focus on components exchanging data gives good composability and testability, both important in IoT. We will program a system with MsgFlo using Flowhub, a visual live-programming IDE, and test using fbp-spec.

At the 2014 IoT devroom, we introduced flow-based programming (FBP) for heterogenous IoT systems, using NoFlo and MicroFlo. The programming model worked well for individual devices, but between the devices of the system our solution caused too tight coupling. When we realized this, we decided to build Msgflo, which reuses many of the same concepts and tools.

In MsgFlo each process/device is an independent participant, receiving data on input queues, and sending data on output queues. A participant do not know where the data comes from, nor where (if anywhere) the data will go. This strong encapsulation gives good composability and testability. MsgFlo uses a standard message queue protocol (MQTT or AMQP). This makes it easy to use with existing software. As each participant is its own process and communicate over networks, they can be implemented in any programming language. Convenience libraries exist for C++, Python, Arduino, Node.js and Rust. On top of the message queue protocol, a simple discovery mechanism is added. For existing devices without native Msgflo support, the discovery messages can be sent by a dedicated tool.

We have used Msgflo in a handful of real-life deployments, and will demonstrate building a simple stand-alone IoT system.

Heterogeneous systems as found in the Internet of Things are made up of many devices of different types working together. Each device class is typically developed with separate tools using different paradigms. We propose that using NoFlo and MicroFlo one can develop heterogeneous systems consisting of micro-controllers, servers, and mobile devices using flow-based programming (FBP) as an unifying programming model.

Systems qualifying for the label "Internet of Things" are often complex hetrogenous systems consisting of many nodes spanning over several device classes, working individually and together to realize the intended function: Microcontrollers w/peripherals are used as sensors and actuators, servers used for data-aggregation and analysis, desktops and mobile devices as user interfaces for monitoring and configuration. Typically each of these classes of device are programmed with separate tools, by different people using different paradigms: for example C/C++ for microcontrollers, Python for servers, JavaScript+HTML5 for user interfaces.

This talks aim to introduce flow-based programming (FBP) as a programming paradigm that can be used across and between device classes, and to show how NoFlo and MicroFlo can be used to implement heterogeneous systems.

About: NoFlo is a JavaScript-based FBP runtime by Henri Bergius, which runs on Node.js and in the browser. http://noflojs.org MicroFlo is a C++ based FBP runtime by Jon Nordby. It runs on AVR and Cortex-M microcontrollers, including Arduino. http://microflo.org

NoFlo and MicroFlo can both be targeted by the NoFlo UI, an IDE for flow-based programming currently in development. Systems can be programmed visually, using a domain-specific language or the runtimes can be embedded and controlled programmatically.

Maliit is an open source project for enabling first-class text input solutions for mobile devices. The project aims to provides a reference solution for easy integration, and a framework that others can build upon. It also strives to work closely with the wider community to improve mobile text input on open platforms. Current examples include its use in MeeGo, Nemo Mobile and Maemo Fremantle, the integration in Qt Components and Libmeegotouch, and improvements made to Qt and GTK+ input method interfaces.

Reviews of mobile devices most often include one or several sections about text input, and how well it works (or not). On-screen keyboard, language support, copy-paste and selection handling, error correction and word prediction, are all fundamental to a good end-user experience. The talk aims to highlight the importance of, and challenges in implementing, modern mobile text input methods on open mobile platforms. It also serves to encourage cross-project collaboration to overcome these challenges and explains how Maliit can provide a solid foundation for this collaboration. Maliit homepage: http://www.maliit.org