Team:NTHU Taiwan/LoRa TTN
LoRa
LoRa is short for long range. It belongs to the group LPWAN (low power wide area network), and is a technology used to transfer data between devices. It is comparable to technologies such as Wi-Fi and Bluetooth, but unlike Wi-Fi, LoRa utilizes a low bandwidth resulting in lower power consumption. Another advantage LoRa has over Wi-Fi is the range at which the devices can be connected. Usually, devices need to be within several meters of a Wi-Fi modem for a strong connection, but using LoRa, devices can be several kilometers from a gateway and still be able to transfer data clearly. However, LoRa does have a downside, the data throughput is really low, only 27 kbps at best. But since we only need to send sensor data and receive simple instructions, this data throughput is still more than enough, which is why our team thinks LoRa is the most suitable tool for our IoT implementation.
Our robotic arm will first gather soil information from the farm using sensors, then using the LoRa communication chip, we will send these data to a LoRa gateway. After the gateway receives data, it will upload these sensor values to an online server via Ethernet or WiFi. Farmers can easily access the soil records via apps on their phones or PCs by connecting to the servers. Based on the data collected in our database, we also designed an app to send alarms to farmers, let farmers control irrigation systems or the robotic arm by sending commands through LoRa using NodeRED. We believe by combining IoT technology with our sensor device, we can make farming simpler and decrease the workloads of farmers. We also hope this technology can attract younger generations to be more willing to return to the withering agricultural industry in Taiwan.
The Things Network
For convenience, we used a free, open LoRaWAN network server called The Things Network to upload the sensor data. The Things Network not only allows us to store sensor data, it also allows us to decrypt the message payloads and use SDKs (software development kits), for our Node-RED applications. Details about Node-Red are explained in Software/NodeRED.
However, do note that because TTN is a free server, it puts stricter restrictions on data rates for both uplink and downlink. In the future, we hope to build our own server and use MQTT for more reliable data transmission.
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