Real Time Coastal Wave Monitor

WiSense developed this prototype for a university in the US. The prototype uses a high resolution pressure sensor to determine wave height and report the same to the cloud in real time. This is intended to replace currently available instruments which log data but do not have radio connectivity to report the data in real time.

We used a LTE CAT1 modem to report the sensor data sampled at 16 Hz. LTE CAT-M and LTE NB-IOT radios are meant for applications which need to communicate infrequently like a water meter which sends a small message every hour or just once every day.

As can be seen in the pics below, the sensor node has two distinct parts – the sensing module and the comms module which are connected by a cable which can be up to 50 meters long.

Sensing Module

  • Analog pressure sensor with exposed diaphragm
  • Signal conditioning circuitry
  • RS-485 Transceiver
  • Waterproof Stainless steel enclosure
  • Waterproof cable connection

Comms Module

  • STM32 Microcontroller
  • RS-485 Transceiver
  • LTE CAT1 Radio
  • Weather proof LTE Antenna
  • LI-Po battery
  • Atmospheric pressure sensor
  • IP67 Enclosure
  • Provision for external power supply
  • Waterproof cable connection

The connecting cable has three functions.

  • As a tether
  • Conveys power to the sensing module.
  • RS-485 data link (Differential signaling suitable for long distances)

Sensor in action (Wilmington, NC)
Comms module

We designed the water-proof stainless steel enclosure from scratch. Here are some 3D renders of the enclosure. The enclosure was machined in Bangalore.

Machine enclosure with sensor and cable

Sensor data showing high and low tides. Top graph – sensor data. Bottom graph – off the shelf logger data

For more information on WiSense, please visit wisense.in.

WTM-4P-110 Update

This is a brief follow up post on the WiSense WTM-4P-110 sensor node designed specifically for wirelessly monitoring the temperature of the cocoa bean fermentation process.

Here is some data from a customer site showing the temperature profile during the fermentation process. The data is from April 30 to May 4 (5 days).

The temperature data shown above is from one of the four sensor probes on the wireless node.

The graph below is showing data from all four sensor probes (inserted in to the same fermentation box).

The graph below is showing the battery voltage over the same period of 5 days. The node is powered by 2 AA batteries. The variation is less than .05 volts even though this node was sending data of all four sensor probes every 1 minute.

See below, a typical fermentation box.

For more information on WiSense products, please visit wisense.in.

See the original post here – https://wisense.wordpress.com/2021/02/07/wtm-4p-110-wisense-wireless-sensor-node-for-monitoring-temperature-during-cocoa-bean-fermentation/

WMB11X-20: WiSense Gateway with ModBus Interface

Here are some pics of the latest version of our Low Power Wireless Mesh Network (LPWMN) gateway with ModBus Interface.

Sub-GHz Radio Options

FCCUSA902-928 MHz
ETSIEU868-870 MHz
WPCIndia865-867 MHz
Non CertifiedAnyAny available ISM Band

For more information on WiSense products, please visit wisense.in

WTM-4P-110 – WiSense Wireless Sensor Node for Monitoring Temperature during Cocoa Bean Fermentation

Our latest product enables Cocoa processors to monitor in real time the temperature of Cocoa beans during the fermentation process.

Battery powered Wireless Sensor Node with 4 Temperature Sensor Probes which can be inserted into a fermentation box.

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3D Rendering of a Cocoa Fermentation Box
(Courtesy ecus@https://3dwarehouse.sketchup.com/)

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Specifications

ComponentSpecsOptions
ControllerUltra low power 16 bit Microcontroller (TI MSP430G2955) Can be upgraded to MSP430F419A or any other variant.
RadioSub-GHz ISM Band Low Power Radio
❏ India: 865 to 867 MHz
❏ EU: 868 – 870 MHz
❏ USA: 902 – 928 MHz

> Multiple raw baud rates supported such as 1.2 kbps, 10 kbps, 20 kbps, 38.4 kbps, 100 kbps
> Modulation: 2FSK / GFSK
> Tx Power: Max 13 dBm
> Note that supported baud rates, modulation, bandwidth, duty cycle and max transmit power are subject to local ISM band regulations (ETSI / FCC / WPC etc)
Certified (FCC/ETSI) and non-certified radio module options available.
AntennaOmni Directional Half Wave Dipole External Antenna
Gain: +3 dBi gain
PCB Antenna / Internal stick-on Antenna with U.Fl connector or any other suitable Antenna.
Power Supply2 x AA batteriesOther options available
> 2 x AAA
> Li-Ion
EnclosureABS Changeable on request
Temperature Sensor> Sensor Count: Min 1, Max 4
> ±0.5°C Accuracy from -10°C to +85°C
> Overall Range: -55°C to +125°C
> Probe Length: 200 mm (Can be made shorter or longer)
Changeable on request
On/Off SwitchMounted on the enclosureChangeable on request
Sleep Mode Power Consumption< 2 Microamps
Reporting IntervalFrom every 1 second to once a day. Configurable (any time) from the cloud
Sensor Node IdentifierUnique IEEE assigned 64-bit address hardwired in onboard EEPROM
Ex: fc:c2:3d:0x00:00:11:0a:1e (all Hex)

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Temperature Data Reporting Options
1Reports measured temperature periodically with a configurable interval – Minimum (1 sec) / Maximum (1 day).
2Reports measured temperature only when it changes by a configurable percentage value with respect to the prior value reported. Also, reports measured temperature if no report sent for a configurable period of time.
3Reports measured temperature only when it crosses a configurable high or low threshold value. High and low hysteresis values are also configurable. Also, reports measured temperature if no report sent for a configurable period of time.
4WiSense can implement any custom temperature reporting algorithm.

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Each sensor data message sent by a sensor node to the cloud (via a WiSense Gateway) conveys the information listed here –
1IEEE assigned 64 bit permanent address of the node (Ex: 0xfc:0xc2:0x3d:0x00:0x00:0x1e:0xf5)
2Battery Voltage (Milli-Volts)
3Sensor Probe #1 Id: 0x6c Temperature: Measured Value (milli-deg C)
4Sensor Probe #2 Id: 0x96 Temperature: Measured Value (milli-deg C)
5Sensor Probe #3 Id: 0x97 Temperature: Measured Value (milli-deg C)
6Sensor Probe #4 Id: 0x98 Temperature: Measured Value (milli-deg C)

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Snapshot of sensor data visualized on the cloud resident WiSense dashboard.
The graph shows data from all 4 sensors.

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WSGWIX-110 – WiSense WiFi Gateway
Collects data from up to 64 sensor nodes and relays to the cloud over WiFi (Other backhaul technologies supported)

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For more information on WiSense products, please visit wisense.in.

Protected: WEM-T8R-100 – Wireless Incubation “Temp + RH” Sensor

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Wireless Incubation Sensor – Data

Graph showing data from seven thermistors
measuring ambient temperature in close vicinity

The graph above shows the ambient temperature measured by seven thermistors on a single sensor egg. Note that the temperature readings are very close to each other as should be because they are all close to each other and measuring the ambient temperature.

The data for this graph was downloaded from the WiSense cloud resident data collection and visualization platform.

The setup has one sensor egg (with seven thermistors) sending data to the cloud (via a WiSense gateway) periodically every 30 seconds. Total of 2880 sensor data messages were sent over a period of 24 hours. Each sensor data message also conveys the voltage of the Li-Ion battery inside the sensor egg.

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Graph shows the battery voltage over a 24 hour duration.
Starting Battery Voltage: 3.94V. Battery Voltage after 24 hours: 3.93V
After sending 86400/30 = 2880 messages, the battery voltage has dropped by only 0.01 V.

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For information on WiSense products, please visit wisense.in.

Protected: Wireless Incubation Sensor – New enclosure

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Protected: Wireless Incubation Sensor

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Protected: Wireless Sensor for monitoring eggs during incubation

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New enclosure for sensor nodes

We are now offering sensor nodes with extruded aluminium enclosure.

Enclosure material is anodized extruded Aluminum

Anodizing is an electrochemical process that converts the metal surface into a durable, corrosion-resistant, anodic oxide finish (anodizing.org).

Extrusion is defined as the process of shaping material, such as aluminum, by forcing it to flow through a shaped opening in a die. Extruded material emerges as an elongated piece with the same profile as the die opening (bonnellaluminum.com).

Pics below show a wireless temperature sensor with an external probe. The extruded aluminium enclosure shown is 94mm x 83mm x 30mm in size. The two end-plates have 4 screws each. We have drilled holes in the end plates for the panel mount U.Fl to SMA RF cable assembly and two LEDs. The opposite end plate has a hole for the sensor cable. This enclosure is not IP rated.

Since the material is a metal, this enclosure is not suitable for applications requiring an internal antenna.

For information on WiSense products, please visit wisense.in