| Sealed enclosure and mounting studWorking at 01 sample | What it does. An aluminium base screwed onto the motor by a steel stud, under a plastic lid sealed with a gasket. The stud carries the motor's vibration into the node, and the plastic lets the radio out. | Why it is hard. How the node is fixed changes what it measures: a stud into a spot-faced hole passes the highest frequencies, a glued pad passes somewhat fewer, and a magnet loses much of the range where early bearing wear shows. The box has to keep out washdown water and oil for years, and a metal lid would block the radio. | Catalogue examples The catalogue has no enclosure or fastener row. |
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| Vibration and temperature sensorsWorking at 01 sample | What it does. An accelerometer on a small board bonded to the base, right over the stud, measures vibration on three axes. A temperature sensor beside it reads the base, which warms and cools with the motor's drive end, lagging the bearing and running cooler than it. | Why it is hard. A damaged bearing shows itself as small, sharp knocks that repeat tens to a few hundred times a second and ring the metal at several thousand cycles a second, so the sensor has to be sampled fast and coupled stiffly to the metal. A sensor on a board that flexes on its standoffs picks up the board's own ringing and loses the bearing. | Catalogue examplesaccel range max 24 g · gyro range max 2,000 °/s · supply voltage 2.4 to 3.6 V temp −55 to 150 °C · accuracy max 0.1 °C · resolution 16 bit The BMI088 is an example of a MEMS accelerometer, built for drones and robots; its datasheet caps its sample rate well below what bearing faults need. A node meant to catch early bearing wear uses an accelerometer specified to several kilohertz; the catalogue has no such row. |
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| MicrocontrollerWorking at 02 filter, 06 update | What it does. A microcontroller sleeps almost all the time. On a timer it wakes, collects a burst of samples, works them down to a few numbers, such as the overall vibration level and the energy in the bands where bearing faults show, and hands them to the radio. | Why it is hard. Every millisecond awake costs battery, and a spectrum takes real arithmetic. The RP2040 listed has Cortex-M0+ cores without a floating-point unit, so the maths runs in fixed point or takes longer. Firmware mistakes are expensive: the box is sealed and bolted to a running machine, so every fix has to arrive over the radio, and an update that fails can strand the node. | Catalogue examplescore 2 · core clock 133 MHz · sram 264 KB core 2 · core clock 240 MHz · sram 512 KB The ESP32-S3 carries its own Wi-Fi and Bluetooth radio, so one chip can do both jobs. Neither row gives a sleep current, which is what decides battery life; that figure comes from each chip's datasheet. |
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| Radio and antennaWorking at 03 send, 06 update | What it does. A Wi-Fi and Bluetooth module at the end of the board sends the summary to the gateway by Bluetooth Low Energy, waits for the acknowledgement, and switches off. | Why it is hard. A plant floor is steel: motors, pipes, and racks reflect and block 2.4 GHz, and a link that works on the day it is installed can fail when a forklift parks in front of it. Joining Wi-Fi can keep the radio on far longer than the send itself, and the antenna needs clear space, so the cell cannot sit over it. | Catalogue examplessupply voltage 3 to 3.6 V · transmit power 18 dBm u-blox marks the NINA-W10 not recommended for new designs; it is listed because its numbers are published and it is widely deployed. |
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| Battery and power monitorWorking at 01 sample | What it does. One 21700 lithium cell powers the node for years. A current monitor on the board measures what each wake costs, so the remaining charge can be estimated and reported. | Why it is hard. Everything the node does is paid for from one cell that nobody wants to change. Left converting, the INA226 listed draws 0.33 mA, which alone would empty the 4,000 mAh cell in about 17 months, so even the monitor has to be put in its shutdown mode between readings. | Catalogue examplescapacity 4,000 mAh · nominal voltage 3.6 V · discharge current max 35 A resolution 16 bit · bus voltage 36 V · supply voltage 2.7 to 5.5 V The cell listed is a rechargeable, high-current cell and shows the size and capacity class. A node built to run for years usually carries a primary lithium cell, which loses less charge sitting on a shelf; the catalogue has no such row. |
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| Gateway on the wallWorking at 03 send, 04 store | What it does. A small computer in a box on a building column listens for the nodes in its part of the plant, timestamps and stores what they send, and forwards it to the server over the plant network or a cellular modem. | Why it is hard. Readings arrive late, out of order, or twice after a retry, and each node's clock drifts. The gateway has to put every reading in order by node and sequence number, and keep what it holds when its own uplink is down. | Catalogue examplescore 4 · core clock 2,400 MHz · memory 8 GB downlink rate max 300 Mbit/s · uplink rate max 50 Mbit/s · transmit power 23 dBm The modem is a mini PCI Express card; on a Raspberry Pi it sits in a USB adapter. A plant with its own network uses the Ethernet port instead. |
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