aE2 (Arduino-E2)

A simple Arduino E2 bus library.

E2Device

This library allows you to communicate with sensor devices using the proprietary E2 bus protocol. This protocol is used by sensors from the manufacturer E + E Elektronik Ges.m.b.H and is quite similar to the I2C bus. It is possible to control devices with two general-purpose I/O pins.

This bit-banging library is based on a similar software by romain.bazile@gromain.me hosted at https://github.com/ubiant/E2. The key differences are subsumized in the notes below. The original library was never released.

Key features

• Clean API
• Sensor identification possible
• No additional dependencies (except Arduino.h)

Constructor

• E2Device(int SDA, int SCL) Creates a new instance of this class taking numbers of two GPIO pins (for data and clock line, respectively) as parameters.

Methods (Getters)

• getTemperature() Returns the temperature reading in °C as float. On error -300 is returned.

• getHumidity() Returns the relative humidity in % as float. On error -1 is returned.

• getStatus() Returns the status of the sensor as a byte. On error 0xFF is returned.

• getSensorType() Returns the type designation of the sensor as String. On error "???" is returned.

• getSerialNumber() Returns the serial number of the sensor as String. On error "???" is returned.

• getFirmware() Returns the firmware version of the sensor as String. On error "???" is returned.

• getSensorDescription() Returns a full description of the sensor. This function is a combination of the three preceeding getters.

Notes

The library was tested with different versions of the E+E EE-07 temperature and humidity sensor. Some methods make use of undocumented calls and my not work with each sensor type.

Support of CO2 sensors and on-sensor memory modification was removed from this version.

Usage

Consult the provided example which show the use of this class.