Telegea Smart Hub
The Telegea Smart Hub is designed to be a gateway between the real world and the communication network targeted mainly at IoT applications. It is a custom hardware built around the RaspberryPi Compute Module and therefore compatible with the software from RaspberryPi ecosystem. It provides a number of standard interfaces for sensors to acquire the data and actuators to control connected devices. Easy to use connectors are provided to ease installation. If needed, functionality can be extended with add-on modules.
The Smart Hub connects to the communication backbone via Ethernet or Wifi (optional) and therefore can provide the data to a cloud service or be controlled remotely.
It is completely user configurable, so different numbers of sensors, actuators or external equipment can be combined with each other. This flexibility allows for many different deployment scenarios which goes from a simple data logging device to a complete smart home solution.
The Telegea Smart Hub is an excellent choice as a Smart Home server device. It can interface with many types of sensors which provide data from around the house. Relay cards can be connected to switch lights, move motorized blinds, open/close doors etc. And it has enough computing power to run the user web interface and the automation rules engine which makes the whole system "smart".
OpenHAB and Home Assistant are two of the most popular open source Smart Home projects which are being developed by their respective communities who also offer support to their user base. Both systems have been tested on the Telegea Smart Hub and will transform this hardware into a fully fledged home automation controller that you can customize to fit your needs.
For device support and installation guides see this GitHub repository.
The Telegea Smart Thermostat was specifically designed for the Telegea Smart Hub hardware which provides easy connection of temperature and humidity sensors as well as relay cards for boiler and A/C units control. Status signals from external equipment as well as pulse signals from energy and flow meters are easily managed. The Smart Hub acts as control device which is accessed via Smartphone app, dedicated touchscreen device and Web GUI. If needed, the controller can be connected to the Telegea cloud backend for advanced data processing, visualization and alarm handling.
The dedicated SmartHub OS, the application software and documentation are available from this GitHub repository.
The Telegea Smart Hub and all of its hardware components are well documented. Specifications and data sheets are freely available. Each component is supported by open source drivers and additional software that can be obtained free of charge and modified to fit specific needs.
In particular the provided hardware is fully compatible with recent Linux Kernels. The customized Linux OS "SmartHub OS" (based on Raspbian Jessie lite) as headless server system is available from the Telegea Github repositories. It gives instant access to all the integrated components and peripheral devices which can be connected to the Hub.
BCM2837 System on Chip (Quad core Cortex A53)
1GB LPDDR2 RAM
Ethernet port (100BASE-TX)
RS485 serial port
RS232 serial debug port
Wifi 802.11 b/g/n a 2.4 GHz (optional)
6 digital inputs via screw terminals (for dry contacts or S0 interface)
4 analog inputs (0-5V) via screw terminals
Dallas 1-wire bus via screw terminals
On board sensor
SHT21 temperature and humidity sensor
2 USB host ports
1 RJ14 connector for I2C bus peripherals
1 RJ14 connector for SPI bus peripherals
1 XBee module compatible connector for ZigBee and other RF modules
3 expansion headers with additional GPIO, SPI and I2C bus connections
5VDC via micro USB connector
9-24VAC/VDC via screw terminals
Real Time Clock with integrated battery
256 byte EEPROM for persistent product data storage
Programmable Push button
Programmable yellow LED
USB OTG port for flash programming
Power supply voltage measurement circuit
Raspbian Jessie Lite, Linux kernel 4.9.x and later
The Smart Hub is realized as a 4 layer printed circuit board with the components mounted on both sides. All materials and components are lead free and follow the RoHS guidelines.
It is 3 times credit card size which is larger than most general purpose Single Board Computers but it has the advantage of providing an easy to use and robust hardware base for IoT and Smart Home tasks. The industrial grade integrated eMMC flash memory provides reliable storage for the Operating System code and configuration data. Screw terminals allow easy and robust connections of sensors and communication busses.
The integrated Real Time Clock keeps track of time and date during short power off periods and reboot as well as unavailability of a network time server. An on board push button and led can be programmed to be used as means of manual user interface if network connection is not available.
The Smart Hub is a typical server device which does not need be in sight of the user and therefore can be conveniently installed in an electrical switchboard. Its size fits a commercial Camdenboss CNMB/9 DIN rail enclosure. As power supply a industry standard 24VDC or 24VAC can be used via the front screw terminals. But for use with a consumer phone charger also a microUSB connector for 5VDC power input is provided at the back of the board.
A dedicated on-board circuit allows measuring the input voltage via 2 of the integrated ADC channels which provides valuable data for the systems health check. If the board is powered with AC power via an AC/AC transformer, even the effective mains voltage can be derived from the ADC measurements.
The integrated digital temperature and humidity sensor provides instant information about the environmental conditions inside the switchboard without the need of extra cabling. This data can be used to raise an alarm in case of exceeding the operating condition limits.
The Raspberry Pi Compute Module, the core of the Smart Hub device, is provided with the Raspbian OS pre-installed on its eMMC flash memory. The OS has been customised and adapted to the specific hardware to make all connected peripherals work "out of the box".
The main changes to the standard version of Raspbian are the following:
- Enable clock generation for integrated Ethernet bridge on GPIO pin
- Enable both UART ports for RS485 connector and serial debug port
- Enable driver for Real Time Clock chip
- Enable driver for Analog Digital Converter chip
- Enable driver for EEPROM chip
- Enable driver for I²C relay card expansion modules
- Configure 1-wire bus on screw terminals
- Install GPIO handling command line tools
- Install Zulu® Embedded OpenJDK Java
Comparison RaspberryPi - Telegea Smart Hub
Being based on the Raspberry Compute Module, the Telegea Smart Hub is compatible with the officially supported RaspberryPi Operating Systems and a wealth of available open source applications. But it offers additional features compared to the "off the shelf" RaspberryPi which make it an excellent solution for semi-professional deployment scenarious. The following table is a summary of the main differences in terms of technical features of the 2 hardware solutions.
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