Cosa is an object-oriented platform for Arduino that supports an event-driven programming paradigm with simple finite state machines. It contains a rich set of classes to support rapid prototyping of Internet-of-Things devices. Cosa supports the following AVR/ATmega/ATtiny internal hardware modules; all pin modes, Digital, and Analog Pins, External and Pin Change Interrupts, Analog Comparator, PWM, Watchdog, Timer0 (RTC), Timer1 (Servo), UART, USI, SPI, TWI and EEPROM.

Though object-oriented with optional operator overloading syntax Cosa is between 2-10X faster than Arduino with regard to digital pin functions. This comes with a small price-tag; memory, 4 bytes per digital pin and 9 bytes per analog pin. Cosa analog pin objects holds the latest sample and allows an event handler. See the benchmarks in the examples directory for further details.

Cosa also contains a data streaming format (Ciao) for encoding of C/C++ language data types such as strings, integer and floating pointer numbers into a binary format. It may be used for a number of applications; tracing, remote procedure calls, data exchange between Arduino devices, etc. The format allows user data types to be defined and values exchanged without additional encoding. The stream header itself is a pre-defined serializable data type. Ciao is used to define an Arduino monitoring and control language (Cosa fai) which has much in common with Firmata. See CIAO.txt for more details and the example code (examples/Ciao).

The primary programming paradigm is object-oriented and state-machine/event driven with proto-threads. There is a large number of device drivers available for SPI, TWI/I2C and 1-Wire. A strict directory structure is used to organize the Cosa/driver source code. Sub-directories are used for each driver type. This allows a foundation for scaling and configuration.

Cosa uses the Arduino IDE and build system. Cosa classes are included with prefix, e.g. "Cosa/FileName.hh". It is possible to use both Arduino and Cosa functions together, though in some cases the Cosa objects may become inconsistent.

To improve debugging and testing there is trace/syslog style support. The IOStream class allows output to both serial communication (UART/VWIO) and small TFT displays (such as the ST7735, ST7564, HD44780 and PCD8544). The Cosa LCD class extends IOStream::Device with additional common LCD functions. The drawing Canvas class supports basic drawing operation and scripting to reduce program memory footprint. The Canvas class also supports drawing of icons and multiple fonts (GLCD and UTFT).

The popular VirtualWire library has been refactored to the object-oriented style of Cosa and extended with three additional codecs; Manchester, 4B5B and Fixed Bitstuffing. This allows basic ultra cheap wireless nodes with RF315/433 receiver and transmitter. For more advanced wireless connections there is also a driver for the Nordic Semiconductor NRF24L01+ chip, which allows low-power wireless communication of up to 2 Mbps in the 2.4GHz band, and the TI CC1101 Low-Power Sub-1 GHz RF Transceiver.

The goal of this project is to provide an efficient programming platform for rapid prototyping of "Internet-of-things"-devices. Unfortunately Cosa is not a beginners entry level programming platform, though following some of the design patterns in Cosa will help beginners build more complex small scale embedded systems with richer concurrency and low power consumption.

The projects main principle of evolution is iterative with many rewrites and refactoring. With that said this phase of the project will require users to align with the interface changes. When interfaces become stable the project will switch to a normal release style.

Please follow the development of this project on blogspot and on the Arduino forum.

The [Cosa zip file] (https://github.com/mikaelpatel/Cosa/archive/master.zip) is an Arduino core package. Download and unzip in your Sketchbook hardware folder. Create the folder if missing. Restart the Arduino IDE and Cosa will show up as a number of boards and example sketches.

For ATtiny a patch is needed for Arduino Windows version to allow linking programs larger than 4K; See https://github.com/TCWORLD/ATTinyCore/tree/master/PCREL%20Patch%20for%20GCC. Do not forget to program the ATtiny device with the bootloader, i.e., set the fuse bits, before using the device for the first time.

The Application Programmers Interface (API) documentation is available online and compressed for download. The documentation contains a full hyperlinked description of all functions in Cosa together with UML graphs of the class hierarchy, include dependencies, and much more.

The provided documentation is generated with doxygen and may also be generated for users source code if the Cosa documentation style is adapted. See the Doxyfile for configuration of doxygen.

1. DS18B20 Programmable Resolution 1-Wire Digital Thermometer.
2. AT24CXX Serial EEPROM.
3. DS1307 Realtime clock with RAM.
4. PCF8591 2-Wire 8-bit A/D and D/A converter.
5. ADXL345 Digital Accelerometer.
6. nRF24L01 Single Chip 2.4GHz Transceiver.
7. DHT11 Humidity & Temperature Sensor.
8. HC-SR04/US-020 Ultrasonic range module.
9. ST7735, 262K Color Single-Chip TFT Controller.
10. PCD8544 48x84 pixels matrix LCD controller/driver.
11. TSOP4838 IR Receiver Modules for Remote Control Systems.
12. Virtual Wire (VWI) on RF315/433 modules.
13. HMC5883L 3-Axis Digital Compass IC.
14. NEXA/HomeEasy Wireless Remote command transmitter/receiver for RF433.
15. ST7565, 65x132 Dot Matrix LCD Controller/Driver.
16. Touch capacitive sensor, debounced button and keypad.
17. Dials with Rotary Encoder.
18. HD44780 (aka 1602, 2004) LCD Controller/Driver.
19. DS3231, Extremely Accurate I2C-Integrated RTC/TCXO/Crystal.
20. PCF8574/PCF8574A Remote 8-bit I/O expander for I2C-bus with interrupt.
21. BMP085 Digital Pressure Sensor.
22. TI CC1101 Low-Power Sub-1 GHz RF Transceiver.
23. Slave device support for SPI, TWI and OWI.

The reference documentation for each device driver hardware module may be found in the references directory.

1. D.tools, http://hci.stanford.edu/research/dtools/
2. Processing, http://processing.org/
3. Wiring, http://wiring.org.co/
4. Arduino, http://www.arduino.cc/
5. Firmata, http://www.firmata.org/wiki/Main_Page
6. LilyPad, http://web.media.mit.edu/~leah/LilyPad/
7. Jeelabs, http://jeelabs.org/
8. Quantum Leaps, http://www.state-machine.com/
9. Concurrency.cc, http://concurrency.cc/
10. Protothreads, http://dunkels.com/adam/pt/
11. Arduino ATtiny, http://hlt.media.mit.edu/?p=1695
12. Arduino Low Power, http://gammon.com.au/power
13. Virtual Wire, http://www.open.com.au/mikem/arduino/VirtualWire/

• "Cosa"; noun thing, matter; pronoun; what?, what!.
• "Che cosa"; pronoun; what.
• "Ciao"; interjection hello!, goodbye!.
• "Cosa fai"; what do you do?

ATtinyX4/X5, and Atmega328P, Atmega1284P, Atmega2560 based Arduino boards (Uno, Mini, Nano, LilyPad, Mighty, Mega, etc) are supported. Arduino and AVR lib functions may be used together with Cosa.

2013-01 Arduino Mega 2560 initial port. UTFT font support added. Proto-threads implemented. Draw/fill round rectangle added to Canvas.
2013-02 Adding doxygen generated documentation (doc.zip). GLCD font support added. IR remote receiver initial example. Adding input/output operators to IOStream, Pins and SPI. More detailed benchmarks and comparison with Arduino added. IOStream driver for PCD8544 48x84 pixels matrix LCD controller with support for fonts and icons. TSOP4838 IR Receiver Modules support (LG remote example). Improving PCD8544 driver with OffScreen canvas. UART receiver, Device::getchar(), implemented. Adding generic circlic buffer for IOStream::Device. Adding support for ATtinyX5. Simple ATtiny monitor included. Adding support for RC Servo. Adding support for ATmega1284P/Mighty boards. Refactoring and porting VirtualWire to Cosa.
2013-03 Virtual Wire Interface (VWI) for ATtiny. VWI IOStream Device to allow streaming of output over Virtual Wire. Introducing Manchester Phase Encoder (MPE) based on VWI. Introducing class for Power Management and Sleep Modes. Refactoring VWI to allow easy update of codecs; VirtualWire, Manchester and Fixed Bitstuffing. Additional codex; Block Coding, B4B5. New VWI example sketches with retransmission; simple client/server example. Introducing an interface for interrupt handlers, and support for pin change interrupts. New directory structure for handling boards. Moving documentation and references to dropbox. Reducing size of download from github.
2013-04 Adding support for HMC5883L 3-axis digital compass. Adding abstraction of EEPROM with default handling of internal EEPROM. Refactoring AT24CXX driver for new EEPROM interface. Implemented 1-wire parasite power mode. Improved DS18B20 1-wire driver and demo sketches with VWI integration. Added support for battery voltage monitoring. New extended mode in VWI with node address, sub-net address matching, message sequence numbering and type handling. NEXA Wireless Remote command receiver (RF433). Added a reliable message passing protocol to the Virtual Wire Interface (VWI). The new class VWI::Transceiver supports message acknowledgement and auto-retransmission. Full support for message parsing.
2013-05 Improving ATtiny support. Adding driver for DHT22. NEXA Wireless Remote command transmitter (RF433). Introducing a new template class for handling of keyed sets of event handlers. Added support for LCD ST7565 with natural text scrolling. Making it easy to implement TWI slave devices with TWI::Device. Including support for event driven Rotary Encoder handler.
2013-06 HD44780 (1602) LCD device driver. Adding support for Sockets. Refactoring NRF24L01P device driver to a Socker::Device with support for both connection-less and connection-oriented communication. DS3231 device driver and example sketches. Driver for the PCF8574/PCF8574A Remote 8-bit I/O expander for I2C-bus with interrupt. Support for 20x4 LCD.
2013-07 Introducing an abstract LCD::Device class and refactoring LCD device drivers. Benchmarking and optimizing LCD device drivers. Added an event driven resistor net keypad handler and support for the DFRobot LCD Keypad shield. Boosting LCD performance to 2-6X faster than Arduino library. Added a new LCD menu system. Refactored Cosa directory structure to match the Arduino core file structure. Performance tuning LCD adapters; additional adapters with shift register support (SR3W and SR4W). Adding Vigenere autokey and RC4 cipher.
2013-08 Updating DHT11/22 device driver. Adding a simple touch capacitive sensor.
2013-09 Major refactoring of SPI and TWI device driver support.
2013-10 Device driver for CC1101 and BMP085 introduced. Introducting an abstract Wireless device interface. Refactoring CC1101 and NRF24L01P to the new interface.