Author Archives: rkris
Our latest product enables Cocoa processors to monitor in real time the temperature of Cocoa beans during the fermentation process.
|Controller||Ultra low power 16 bit Microcontroller (TI MSP430G2955)||Can be upgraded to MSP430F419A or any other variant.|
|Radio||Sub-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.|
|Antenna||Omni 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 Supply||2 x AA batteries||Other options available|
> 2 x AAA
|Enclosure||ABS||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 Switch||Mounted on the enclosure||Changeable on request|
|Sleep Mode Power Consumption||< 2 Microamps|
|Reporting Interval||From every 1 second to once a day.||Configurable (any time) from the cloud|
|Sensor Node Identifier||Unique IEEE assigned 64-bit address hardwired in onboard EEPROM|
Ex: fc:c2:3d:0x00:00:11:0a:1e (all Hex)
|Temperature Data Reporting Options|
|1||Reports measured temperature periodically with a configurable interval – Minimum (1 sec) / Maximum (1 day).|
|2||Reports 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.|
|3||Reports 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.|
|4||WiSense can implement any custom temperature reporting algorithm.|
|Each sensor data message sent by a sensor node to the cloud (via a WiSense Gateway) conveys the information listed here –|
|1||IEEE assigned 64 bit permanent address of the node (Ex: 0xfc:0xc2:0x3d:0x00:0x00:0x1e:0xf5)|
|2||Battery Voltage (Milli-Volts)|
|3||Sensor Probe #1 Id: 0x6c Temperature: Measured Value (milli-deg C)|
|4||Sensor Probe #2 Id: 0x96 Temperature: Measured Value (milli-deg C)|
|5||Sensor Probe #3 Id: 0x97 Temperature: Measured Value (milli-deg C)|
|6||Sensor Probe #4 Id: 0x98 Temperature: Measured Value (milli-deg C)|
For more information on WiSense products, please visit wisense.in.
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.
For information on WiSense products, please visit wisense.in.
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
The WiSense IoT dashboard offers real-time sensor data collection and visualization on the cloud. The dashboard has a powerful relational database storage with fast response time for UI data updates. The UI comes with various visualization options and also supports configurable SMS/Email alarm generation features.
WiSense builds and maintains this dashboard for our customers. Our customers can use it even when they are not using WiSense hardware.
The dashboard can run in the cloud or locally within customer premises.
The snapshots below show a simple dashboard built for a customer’s factory having five WiSense WXI-RH/T-10 wireless sensor nodes sending relative humidity and temperature data to the cloud.
The customer has a (WiSense provided) login id and password to access this data.
The snapshot below shows the visualization screen which can show both real time and historic data. This particular snapshot is showing temperature (T) and relative humidity (RH) data stream from a WiSense WXI-RH/T-10 wireless sensor node installed in chamber 01.
The snapshot below shows the last received sensor data and associated time stamp from the sensor node in chamber-01. In addition, this screen allows the generation of e-mail/SMS alerts through configuration of sensor data thresholds for each sensor data stream.
I will take the relative humidity (RH) data to illustrate the threshold settings. The snapshot shows the upper threshold set to 80 %, the lower threshold set to 40 % and a hysteresis value of 2.5 %. The corresponding chamber will enter an alarm condition when –
- RH rises above 80 %
- Here the chamber enters the alarm condition “RH above upper threshold”
- RH falls below 40 %
- Here the chamber enters the alarm condition “RH below lower threshold”
The chamber is not in any alarm condition as long as the RH value is between 40 % and 80 %.
The hysteresis value of 2.5 % prevents unnecessary alerts (e-mail/SMS) from being generated in case the RH value fluctuates around the threshold value. It is up to the customer to choose the appropriate threshold and associated hysteresis value.
The dashboard will send out a e-mail and/or SMS to configured recipients if alert generation is enabled (“yes”) for the corresponding sensor data (see snapshot above) stream. An alert e-mail and/or SMS is sent when an alarm condition is entered as well as when the alarm condition gets cleared.
If customer has not enabled alert generation (“no”) for a particular sensor data stream, no e-mail/SMS will be sent out but this event will be recorded and displayed in the “alarms” history window shown in the snapshot below.
Once an alert (e-mail and/or SMS) is sent out, another alert will not be sent out until the alarm condition gets automatically cleared or a different type of alarm condition is entered. For example, if the RH value increases beyond 80%, the chamber will remain in this alarm condition until the RH drops below (80 – 2.5) = 77.5 %. Similarly, if the RH falls below 40 %, the chamber will remain in this alarm condition until the RH rises above (40 + 2.5) = 42.5 %.
For more information on our products, please visit wisense.in.
For inquiries about our dashboard, please write to us at firstname.lastname@example.org.
WiSense is now offering a “Relative Humidity and Temperature Sensor” (WXI-RH/T-10) for demanding applications.
WXI-RH/T-10 (With internal Antenna)
The sensor itself is located inside a 3D printed enclosure. It is connected by a cable to an IP-65 enclosure containing all the electronics (micro-controller, Radio, Battery etc).
The sensor node can be customized according to customer requirement. Here is a list of customizable components –
- USA – FCC compliant (902 – 928 MHz Ban)
- EU – ETSI compliant (868 MHz Band)
- India – WPC Compliant (865-867 MHz Band)
- We can replace standard sensor with customer specified sensor
- We can also include more than one sensor of any type. Each sensor node can support multiple sensors.
- Internal to the enclosure
- External (connected to the radio through panel mount U.Fl to SMA cable assembly)
We can change the enclosure based on customer specified material, dimensions and ingress protection rating. The default is an ABS enclosure, 120 mm x 80 mm x 55 mm in size and IP-65 rating.
Specs of the default sensor used in WXI-RH/T-10
- Temperature Sensor
- Operating Range: -25°C to +60°C
- Resolution: 14 bit (0.01°C)
- Accuracy: ±0.3°C
- Repeatability: ±0.1°C
- Drift: < 0.05 °C/yr
- Humidity Sensor
- 0 to 100% Relative Humidity ( Non- Condensing)
- Resolution: 14 bit (0.01%RH)
- Accuracy: ±2.0%RH
- Repeatability: ±0.2%RH
- Drift: < 0.5 %RH/yr (Normal condition)
- Filter cap to resist condensation.
Here is a snapshot of the WiSense cloud dashboard showing sensor data received from a customer’s factory. The wireless sensor node is inside a steam chamber with relative humidity reaching 99 % and temperature above 40 deg C.
Pic below shows a steaming chamber in which one of the sensor nodes was placed. The sensor nodes are sending data to an external gateway node with WiFi back-haul (WSGWIX-110).
For more information on WiSense products, please visit wisense.in.
We are going to offer our own SIM868 daughter board in the coming weeks. We are currently testing some of the boards we have assembled.
The SIM868 is a Quad-Band GSM/GPRS + GPS module. The SIM868E modules has BT LE modem in addition. The two modules are pin compatible.
Fully Assembled SIM868/SIM868E Daughter Board
- Modem: SIM868 / SIM868E (U2)
- SIM Holder: Micro SIM card holder (J1)
- Dimensions: 60 mm x 40 mm
- PCB Thickness: 1.6 mm
- Antenna Connectors
- U.Fl RF connector for GSM/GPRS Radio Antenna (P2)
- U.Fl RF connector for GPS Antenna (P1)
- U.Fl RF connector for BT module (P3) – SIM868E only
- Power Supply
- VBAT on J3 powers the SIM868 (Both the GSM/GPRS and GPS parts)
- VBAT should be between 3.4V and 4.4V. Recommended voltage is 4.0V.
- VBAT should be able to supply up to 2A.
- Mounting Options
- This board has been designed to be used as a daughter board mounted on a base board using castellated mounting holes.
- Four groups of castellated mounting holes (J2, J3, J5 and J9).
- External Interface
- This board can run on a voltage (VBAT) which can be different from the voltage (V_HOST) at which an external host controller/processor (to which this board is interfaced) operates. This requires V_HOST to be supplied to this board through a pin on castellated connector J5.
- Voltage translated UART Tx and Rx signals. A voltage translator IC is used which take V_HOST and VDD_EXT as input. VDD_EXT is generated by the SIM868/SIM868E module.
- PWR_KEY (Power ON/OFF control)
- This signal can be used to power on / power off the SIM868/SIM868E module.
- When signal is low, module is powered off.
- To power cycle the module, bring signal low and then take it high.