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Summary
Summary
HobbyIoT NET is an Open source wireless sensor network adventure. The solution concept was developed around the general idea to have a fully open source, easy to program and upgrade, easy to implement and cheap IoT solution.
All modules are Arduino compatible. The connectivity is based on the low power 802.15.4 transport running the MQTT-SN protocol right over it to have the simplest and shortest messages possible. The Gateway supports up to 1024 end devices and translates messages to and from standard MQTT protocol.
We are currently looking into the opportunity to join the "Works with Arduino" partner program.
The HobbyIoT NET is an MQTT-SN protocol implementation over 802.15.4 physical connection. It connects together number of End devices - MQTT-SN Clients - capable to measure and control various parameters and appliances. Each End device connects to the MQTT-SN Gateway and exchange information over it with the MQTT Server. This server can either just pass the information or - if programmed - make decisions how to manage the sensor network by itself.
The network
The network
General
General
The network lets you monitor and manage various sensors and appliances over 802.15.4 wireless links to the Gateway (GW). It concentrates the data and translate the MQTT-SN messages into MQTT in both directions to and from MQTT Broker.
All the data is then available to see and manipulate by any MQTT Client end device - smartphone or computer.
Network elements
Network elements
Sensors and Actuators - End devices based on Arduino with 802.15.4 transceiver, MQTT-SN Client software and set up
MQTT-SN Gateway (GW) - Arduino with 802.15.4 transceiver, MQTT-SN GW software and set up
MQTT Broker - Most likely Raspberry Pi
MQTT Client - Any smartphone or computer
Sensors
Sensors
End devices can be various types and constructions. They are able to collect and send information to the Gateway or do some action if a command is received. from the Gateway. The system operates according the MQTT-SN Specifications.
Upon start any client sends CONNECT message to the Gateway. After acknowledged by CONNACK the End device has to periodically send PINGREQ and waits for PINGRESP from the Gateway. In case of timeout the whole procedure starts from the beginning.
Any End device can publish a message to the Gateway. Publishing is made via so called Topics. If the Gateway knows about such topic it will process it. Otherwise the information will be discarded.
To receive a message the End device must first subscribe for such Topic by sending SUBREQ command to the Gateway. The SUBACK is sent back from the Gateway. From now on when the Gateway receives a message under that Topic, it will be send to all subscribed End devices.
Visit the sample diagrams of End devices and Gateways together with the available software sources and descriptions at the end ot that page.
MQTT-SN_LED_Video_1.mp4The Gateway
The Gateway
The Gateway is built on the ESP12 NodeMCU module. It has a hardware WiFi integrated memory and pins enough. It is connected to the MRF24J40MA transceiver module to connect to the End devices. At the other side messages are translated into MQTT protocol and exchange over a WiFi network.
Gateway firmware on GitHub: MQTT-SN_GW_802154_V1
Platform
Platform
MQTT Server can be built on any suitable device like Raspberry Pi or any other computer. More information of how to install and set up the MQTT Server on Raspberry Pi can be found here.
MQTT Server and Gateway have to see each other over an IP network.
Sample schematics
Sample schematics
End device Type 1 THR XLP (Low power)
End device Type 1 THR XLP (Low power)
Sleep mode Current consumption down to 4 uA
This is the End device Type 1 THR Extra Low power shcematic. When sleeps it only consumes 4 uA from the power source (measured at VCC = 3.3V). Both DHT11 and MRF24J40MA are powered by Arduino I/Os and are being switched on only when needed.
The 3.3V regulator has to be removed or disconnected as shown.
Charts below show the current consumption reduction down to 4 uA together with the consumption profile.
Source code is available on GitHub.
End device Type 1 THR
End device Type 1 THR
This is the client circuit schematic using Arduino ProMini working on 3.3V, MRF24J40MA transceiver module, DHT11 and a reed sensor. The overall schematic combines the Temprature and Reed sensors shown below within one single device: Type 1 THR
End device - temperature sensor
End device - temperature sensor
This is the client circuit schematic using Arduino ProMini working on 3.3V, MRF24J40MA transceiver module and a DHT11 sensor. The End device publishes periodically the temperature value read from the sensor on specific topic. No level shifter is required when using Arduino ProMini.
Powering can be via Arduino board's RAW input by using 9V battery.
End device - reed sensor for door/window
End device - reed sensor for door/window
This is the client circuit schematic using Arduino ProMini working on 3.3V, MRF24J40MA transceiver module and a reed sensor for door or window control. The End device publishes events of door/window open or close once occured. No level shifter is required when using Arduino ProMini.
Powering can be via Arduino board's RAW input by using 9V battery.
End device - LED (any kind of actuator)
End device - LED (any kind of actuator)
This is the End device circuit schematic using Arduino NANO/Iteaduino NANO, MRF24J40MA transceiver module and a LED. The End device subscribes for a specific topic and then waits for a command on the same topic to power the LED ON and OFF. You will also need a level shifter block and a capacitor for the transceiver power rail.
Actuator End device firmware on GitHub: MQTT-SN_802.15.4_Client
The Gateway
The Gateway
The Gateway is built on the ESP12 NodeMCU module. It has a hardware WiFi integrated memory and pins enough. It is connected to the MRF24J40MA transceiver module to connect to the End devices. At the other side messages are translated into MQTT protocol and exchange over a WiFi network.
Gateway firmware on GitHub:
MQTT Server
MQTT Server
MQTT Server can be built on any suitable device like Raspberry Pi or any other computer. More information of how to install and set up the MQTT Server on Raspberry Pi can be found here.
MQTT Server and Gateway have to see each other over IP network.
Resources
Resources
Project links
Project links
Hardware design: https://circuitmaker.com/Projects/Details/sivanovbg/HIOTTHRV2-1
Software design: https://github.com/sivanovbg/MQTT-SN_802.15.4_DeviceT1_THR_RLP
GitHub resources: https://github.com/sivanovbg
Slack: https://join.slack.com/t/hobbyiot/shared_invite/zt-5y9rthol-h1NUJFP5x2N7XXeW99dsiw
Technology links
Technology links
MQTT-SN Specs: http://www.mqtt.org/new/wp-content/uploads/2009/06/MQTT-SN_spec_v1.2.pdf
MQTT Official webpage: http://mqtt.org/
MQTT-SN Specs: http://mqtt.org/new/wp-content/uploads/2009/06/MQTT-SN_spec_v1.2.pdf
Arduino website: https://www.arduino.cc/
NodeMCU websites: http://nodemcu.com/index_en.html, https://erelement.com/wireless/nodemcu
MRF24J40MA Specs: http://ww1.microchip.com/downloads/en/DeviceDoc/70329b.pdf
MRF24J40 IC Specs: http://ww1.microchip.com/downloads/en/DeviceDoc/39776C.pdf
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