Introducing Plant Floor IoT Platforms Requires Wireless Sensors

There is an increasing demand for wireless technology, especially on plant floors, as it significantly reduces installation cost. With the synergy of affordable microcontrollers and MEMS chips, there is a low barrier to starting IoT condition monitoring or predictive maintenance. In social infrastructure IoT projects, the sensor or local equipment data is often sent to a cloud server via the Internet. However, on plant floors, the ultimate destination of sensor data is normally a local network such as a control or diagnostic network. Popular on-premise, closed, wireless technologies include WiFi, Bluetooth, or Zigbee. However, considering crowdedness, transfer quality, and power consumption, most projects now choose an ISM band of 915-930MHz, 886Hz in Japan, or 920MHz in the US, known as the LoRa band.

Wireless Sensor Network Architecture

We implemented a unique modulation system on a wireless chip from Semtech, achieving reachable distance of 100m and a speed of close to 300kbps, which is ten times faster than LoRa. To send distance transmissions over 10km, information can also be sent via LoRa modulation.

Connecting to our Industrial Raspberry Pi via a USB wireless receiver, the rMICA-master becomes a wireless “parent” which can communicate with multiple wireless sensor boxes dubbed “children”. Since the parent connects with each child one by one, depending on data size and transmission frequency, there is a maximum number of wireless sensor boxes per receiver.

In 2010, the sub-giga band in Japan (915 to 930MHz) was released and allocated to wireless sensing and UHF RFID tags. There are a total of 38 channels available (24-61CH), but some channels are shared with UHF RFID tag communication. Thus consider confirming which channels are available prior to setting up a network. Additionally, if more than one independent wireless network is needed at the same site, choosing two channels can allow this to be set up.

rMICA Product Portfolio

USB Wireless Receiver

920 MHz Wireless host receiver to connect MICA-R using special USB cable


1x USB: M8 4pin, male
1x antenna: RMA, female

Wireless Box for Acceleration Sensor

920MHz Wireless sensor box for acceleration sensor. Long-time measurement with integrated large-volume battery of 13.5mAh


1x sMICA-ACC: M8 8pin, female
1x antenna: RMA, female