Monthly Archives: June 2020

RH/T Sensor with 3D Printed Enclosure

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 –

Radio

  1. USA – FCC compliant (902 – 928 MHz Ban)
  2. EU – ETSI compliant (868 MHz Band)
  3. India – WPC Compliant (865-867 MHz Band)

Sensor

  1. We can replace standard sensor with customer specified sensor
  2. We can also include more than one sensor of any type. Each sensor node can support multiple sensors.

Antenna

  1. Internal to the enclosure
  2. External (connected to the radio through panel mount U.Fl to SMA cable assembly)

Enclosure

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.

SIM868 / SIM868E Board

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

Details

  • Modem: SIM868 / SIM868E (U2)
  • SIM Holder: Micro SIM card holder (J1)
  • PCB
    • 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
      1. VBAT on J3 powers the SIM868 (Both the GSM/GPRS and GPS parts)
      2. VBAT should be between 3.4V and 4.4V. Recommended voltage is 4.0V.
      3. 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
    • V_HOST
      1. 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.
      2. 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)
      1. This signal can be used to power on / power off the SIM868/SIM868E module.
      2. When signal is low, module is powered off.
      3. To power cycle the module, bring signal low and then take it high.

References