Author Archives: rkris2013
We are adding a new product to our portfolio – a WiFi gateway for the WiSense LPWMN (low power wireless mesh network). This gateway (WGP20CL) includes a WiSense coordinator node (the WSN1120CL) and a Photon WiFi board from Particle (https://www.particle.io/).
Here are the specs.
WiFi Interface: Photon from Particle (https://www.particle.io/)
Based on Cypress’s WICED architecture, the Particle Photon Series combines a powerful STM32 ARM Cortex M3 micro-controller and a Cypress Wi-Fi chip.
WiSense LPWMN Interface : WSN1120CL WiSense LPMWN Coordinator.
Power Supply: 500 mA/5V through USB Cable with Type A connector.
Includes 2200 mAh battery and Li-Ion charger with auto switch over in case external power is lost.
- External Sub-GHz half-wave dipole antenna (3 dBi gain). Connects to the U.Fl connector on the WSN1120CL’s radio board.
- External 2.4 GHz WiFi dipole antenna (2 dBi gain). Connects to the U.Fl connector on the Photon.
Enclosure: ABS Box (105 mm x 105 mm x 62 mm)
Visual indicators: 3 LEDs
- LED1: Heart beat to indicate the gateway is powered and running.
- LED2: Blinks whenever the Photon receives a sensor data message from a sensor node via the attached coordinator node.
- LED3: Blinks whenever the Photon posts sensor data to the Particle cloud.
Cloud interface: Particle cloud platform. Particle also allows data to be forwarded to other platforms such as ThingSpeak, Google Cloud platform, Google maps, Azure IOT platform etc.
We have ported a portion our gateway application to the Photon. This code receives sensor data messages from the attached LPWMN network and forwards them to the Particle cloud. We have also tested Particle’s integration with the ThingSpeak platform. We are able to get our sensor data on the ThingSpeak platform via the Particle cloud.
For more information on our products, please visit wisense.com.
This week we sent data from bunch of WiSense sensor nodes to the thingSpeak cloud platform. The wireless sensor nodes were registered to a WiSense network coordinator (WSN1120CL) which in turn was connected to a Windows laptop running our gateway application (a C program running under Cygwin).
“ThingSpeak” is an IOT analytics platform that allows the collection,storage, visualization and analysis of sensor data in the cloud. You can create a free “ThingSpeak” account which limits the per channel data streaming (upload) rate of once every 15 seconds.
The WiSense gateway app (which can be run a Linux system or under Cygwin on a Windows machine) sends data to the “Thingspeak” platform when run with the “mon_ts” command line argument instead of the usual “mon” command.
prompt> ./gw.exe / dev/ttyS9 mon_ts
Note that each WiSense sensor node is permanently identified by it’s 64 bit extended address which looks like “0xfc:0xc2:0x3d:0x00:0x00:0x1e:0xd0:0x40”. This is an IEEE assigned globally unique id.
We decided to create a separate “ThingSpeak” channel for each WiSense sensor node.
“Channels store all the data that a ThingSpeak application collects. Each channel includes eight fields that can hold any type of data, plus three fields for location data and one for status data. Once you collect data in a channel, you can use “ThingSpeak” apps to analyze and visualize it.”
Each “Thingspeak” channel can have up to 8 sensor data fields. We map each sensor (on a WiSense sensor node) to a separate field. A free “Thingspeak” account accepts channel data once every 15 seconds only.
We use a text file named “ts.txt” to associate a WiSense sensor output (each having a unique 8 byte extended address) to its corresponding field in a “Thingspeak” channel. The WiSense gateway app reads and parses the “ts.txt” file when run with the “mon_ts” argument. When this app receives sensor data from any sensor node in the attached WiSense LPMWN (low power wireless mesh network), it looks up this table for a matching row and if found, sends the sensor data to the ThingSpeak cloud using the HTTP “POST” method specifying the channel API key and field.
The mapping table below is the actual “ts.txt” used in our setup.
<$< fc:c2:3d:00:00:00:db:40 NCT4JOQR1ZI5DEHB 013 field1 >$>
<$< fc:c2:3d:00:00:02:b9:9b 4WZBK65FZNTO6JWS 013 field1 >$>
<$< fc:c2:3d:00:00:10:82:97 XXTNNZSMAZQKMIL5 009 field1 >$>
<$< fc:c2:3d:00:00:11:1a:ea ZBT7N4IKJKCND80L 120 field1 >$>
<$< fc:c2:3d:00:00:11:1a:ea ZBT7N4IKJKCND80L 009 field2 >$>
<$< fc:c2:3d:00:00:11:1a:ea ZBT7N4IKJKCND80L 176 field3 >$>
<$< fc:c2:3d:00:00:11:1a:ea ZBT7N4IKJKCND80L 177 field4 >$>
For each unique sensor data stream produced by a WiSense sensor node, there is one row in the mapping table.
- The first column is the 8 byte IEEE assigned globally unique address of a WiSense sensor node.
- The second column is the Write API Key of the associated “ThingSpeak” channel. Note that one “ThingSpeak” channel needs to be created per WiSense sensor node.
- The third column is the 1 byte device-id of the Sensor output (example – ambient temperature) sent by the WiSense node. Note that if a single sensor has multiple outputs (such as both temperature and relative humidity), then each output will be assigned a separate device id.
- The fourth column indicates the channel field assigned to this particular sensor output.
The mapping table shows four different Write API Keys each corresponding to a unique “ThingSpeak” channel. The last four rows have the same Write API Key and correspond to the 4 different sensor outputs received from the associated WiSense sensor node. Note that each of these four rows has a unique field column.
In the table above, the different sensor output ids are –
- 013 : NTC thermistor data (NXFT15XH103 from Murata).
- 009: LM75B temperature data (NXP)
- 120: MSP430 On chip supply voltage data (TI)
- 176: RH data from a CC2D33S sensor (Amphenol advanced sensors)
- 177: Temperature data from a CC2D33S sensor (Amphenol advanced sensors)
Here is a snapshot of the sensor data visualized by ThingSpeak for one of the sensor nodes with four sensor outputs (the last four rows in the mapping table at the top).
Here’s a pic of the setup showing a windows laptop running the WiSense gateway app under Cygwin, a WiSense coordinator node connected to the laptop and a WiSense sensor node generating 4 sensor output streams corresponding to the last 4 rows in the mapping table shown above. The laptop is sending data to the ThingSpeak cloud over a WiFi/broadband connection.
For more information on our products, please visit wisense.in.
Albert (our 3D printing expert) is designing enclosures for our wireless temperature sensor tags. We have gone through a few 3D printed versions already. The enclosure material is ABS.
These tags are suitable for sensing temperature indoors (warehouses, cold chains etc). You can see the sensing element (a thermistor) sticking out of the tags. These tags are powered by two coin cells (3V CR2032) which can last more than three years assuming 1 transmission every 5 minutes. The tags have an internal PCB antenna but also have a U.Fl connector for an external whip antenna.
The tags operate in the 865-867 MHz license free band in India.
Please visit wisense.in for more information on our products.
We are currently testing our smallest form factor wireless temperature sensor node.
Dimensions: 50 mm x 50 mm x 10 mm.
- External whip antenna
- Internal PCB antenna
The temperature is sensed by a thermistor with 1% tolerance. Thermistor is visible outside the enclosure
Powered by a single CR2032 coin cell battery with 220 mAh capacity and 3V nominal voltage.
Transmit power of +12 dBm
Operates in the 865-867 MHz license free India band. Operating at this frequency has the following advantages:
- This band is mostly free throughout India so very low possibility of interference.
- 3 times higher range compared to 2.4 GHz (assuming same link budget)
- Greater penetration through obstacles such as walls etc
The sensor node is configured to operate as a reduced function device which means that the node is sleeping in low power mode most of the time, only waking up to sense and transmit temperature data if absolutely required. Sleep mode power consumption is less than 2 micro-amps.
Sensor node can send data to a WiSense LPWMN coordinator node (WSN1120CL) directly or indirectly through one or more WiSense LPWMN routers/FFDs (WSN1120L).
Each message from sensor node also reports the battery voltage.
Sensor node can be configured to –
- Report temperature data at fixed intervals where the reporting interval can be dynamically adjusted from every 1 second to once every day.
- Report temperature data when temperature drops below or rises above configurable threshold values.
- Report temperature data only if temperature changes by a configurable percentage or absolute value in deg C.
- Any combination of the above.
- Report battery voltage and temperature data if battery voltage falls below configurable threshold.
For more information, please visit wisense.in.
This is the latest addition to our product line. We are already deploying these at couple of customer facilities (factories).
This asset tagging system has these components:
Active Tags – Each tag has a radio (sub-GHz or 2.4 GHz) and a tiny micro-controller. It is powered by a 3V Li-Ion coin battery which can last for 7-8 year assuming one beacon transmission per day. Each transmitted beacon carries the tag’s unique 3 byte hardwired Id. The tag has a PCB antenna.
Reader-Router Nodes – These nodes pick up the beacons received from all tags in the vicinity and forward the same to the system gateway. These nodes have two radios each operating on a different frequency. One radio is always listening for beacons from the active tags and the other radio is used to form a mesh network of router radios. This mesh network is used to forward the beacons and associated information (reader node “Id” and the signal strength of the received beacon) to the system gateway. The reader-router nodes should be distributed throughout (say a factory) in such a way that each beacon is received by 3 or more nodes. This allows the system to estimate the rough location of each tag using the signal strength information corresponding to each received beacon. These nodes are mains powered with Li-Ion battery backup. A Li-Ion charger IC keeps the battery charged when mains power is available. When mains power is lost, the node gets power from the Li-Ion battery without any interruption.
System Gateway – The gateway is the asset tracking system’s to the external world. It also maintains the mesh network of router radios.
Tag UI and database – This can be hosted locally or on the cloud. The database will store all the beacons forwarded to the gateway. The UI shows the location of all tags in real time.
For more information, please contact us at email@example.com.
WiSense is proud to be associated with the “Roads that honk project.
More good news – “India’s sole Innovation shortlist at Cannes Lions 2017 goes to Leo Bunett”.
WiSense low power wireless nodes provide the link between the two poles. In addition, we designed the main controller PCB inside each pole and helped in the developing the firmware.
Thanks to Rajeev jha (Yuktix) and Shailendra singh for the opportunity to work on this project.
This week we got a antenna stand 3D printed. The stand keeps our half-wave dipole antennas up right on a flat surface. The antenna can be snapped in to one of three holders. Useful to have when doing some testing without using an enclosure.
I have some pics of the setup below showing a WSN1120L sensor node connected to an antenna through a U.FL to SMA cable assembly.
Thanks again to Hack Lab for help with the design and printing.
For information on our products, please visit wisense.in.
Pic below shows a WSN1120L based sensor node equipped with two float switches and a temperature sensor for tracking the level and temperature of a CNC machine’s coolant tank.
Pic below shows another WSN1120L based sensor node equipped with an NTC thermistor for measuring motor temperature.
Both the nodes (shown above) run on a pair of AAA batteries. The WSN1120L wireless sensor node (in each case) is configured to operate as a reduced function device (RFD). The node wakes up periodically (depending on the application), samples the attached sensors, sends data to the network gateway and goes back to sleep. The battery voltage level is also measured and reported in every sensor data message sent to the gateway.
All the electronics is protected by a low cost weather proof enclosure.
For more information on our products, please visit wisense.in.
This week we tested our new Telit GL868-Dual GSM/GPRS board. The GL868-Dual is a dual band 900/1800 MHz GSM/GPRS device.
This board is suitable for providing cloud connectivity to a remote instance of a WiSense wireless mesh network. The board can work directly off a Li-Ion battery which could in turn be charged by a solar panel or even mains AC if available.
This board can be easily interfaced to a Raspberry PI using an USB to serial (RS-232) adapter. The 5V output of the Raspberry PI should be used to power the board’s comm interface (see supply (2) below).
The GL868-Dual board can also be interfaced to an external micro-controller such as the MSP430 on a WSN1120CL coordinator node. The external micro’s supply voltage can be different from the power supply provided to this board. This is possible since this board utilizes voltage translator ICs for all exposed GL868-Dual signals. The external micro’s supply voltage should be used to power the board’s comm interface (see supply (2) below).
The GL868-Dual peak current draw is around 2 Amps.
- Power supply (1): 3.8V to 4.2V (Allows the board to work directly off a single cell Li-Ion battery) through 4 pin screw less terminal block.
- Comm interface voltage supply (2) allows board to be interfaced with external micro-controller / R-PI etc through multiple voltage translator ICs. This is independent of the power supply (1) mentioned earlier.
- Mini-SIM card holder
- Comm interface:
- RS-232 (TX/RX) through a DB-9 connector
- UART (TX/RX) on 2.54 mm pitch headers.
- Other exposed GL868-Dual signals (through voltage translator ICs) on 2.54 mm pitch headers.
- External signal which controls a load switch gating power supply (1) to the GL868-Dual modem.
- Antenna connection through u.fl connector.
- Layers: 4
- Dimensions: 69 mm x 82 mm
- Finish: ENIG
- Mounting holes: 4
- All components mounted on top side.
Here is a pic of the board.
For more information on WiSense products, please visit wisense.in.
We got a 3d printed enclosure for our soil moisture sensor thanks to Vikram Rastogi who runs Hacklabs.in (co-located at Nasscom COE-IOT). This was our first experience with 3d printing and we are happy with the outcome.
The 3d enclosure has two parts. The top part can be screwed on/off the longer bottom part.
The moisture sensor is connected to a WiSense WSN1120L sub-GHz wireless node through 4 wires (2 for power and 2 for the I2C bus).
In the pic below, you can see the soil moisture sensor connected to the WSN1120L mounted inside another weather proof enclosure.
Here’s a close-up of the 3d printed enclosure.
Here’s a pic showing the sensor in action outside Nasscom COE-IOT in Bangalore. The soil moisture data is being sent (every 5 minutes) to our data collection/visualization application “WiSight” running on AWS.
Here is a snapshot of the sensor data from WiSight.
For more information on WiSense products, please visit wisense.in.