Solar powered 4-20mAh pressure transducer IoT

WisBlock
1

Hello guys,
I came about WisBlock while looking for Arduino parts for my project… brand new to WisBlock so need you help on my first project.

I work for a hazmat transportation company; we want to build a solar powered solution to be installed on our gas tank trailers that sends a 4-20mA pressure transducer readings along with GPS data.

Our device should wake up every X minute:

  1. Get the reading from the 4-20 pressure transducer
  2. Get GPS location
  3. Send information via LTE
  4. Sleep

After extensive reading I came up with this hardware list:

  • Base: Dual IO Base Board with Power Slot | RAK19011
  • Core: Nordic nRF52840 BLE Core Module for LoRaWAN with LoRa SX1262 | RAK4631
  • IO1: 4-20mA Module STMicroelectronics LM2902 | RAK5801
  • Power: USB LiPo Solar Power Slot Module | RAK19012
  • Solar and enclosure: Unify Enclosure IP67 150x100x45mm with solar panel
  • Battery: 3.7v 3200 mAh Link
  • IO2: Not sure which one to get:
  1. NB-IoT LTE CAT M1 Quectel BG77 | Cellular IoT Module | RAK5860
    or
  2. GSM Quectel MC20CE | RAK13101

I want to power the 4-20 transducer directly off the RAK5801 module, the pressure transducer is an 8-12V input 4-20 mA: Link

Questions:

  1. Would WizBlock be a correct option overall? High vibration from the road is to be expected.
  2. Which cellular module is best for my use? RAK5860 or RAK13101
  3. I will not be using any other connectivity other than cellular, should I get other core module? (maybe having LoRa and BLE increases the power consumption?)
  4. What would the power consumption taking into consideration the pressure transducer looks like? Do you think this is feasible?
2

Welcome to RAK forum @adolfoalonso ,

Good to know you are considering WisBlock in your application.

To answers your questions:

  1. Compared to other modular modules, WisBlock has better immunity to vibrations with its board to board connector secured with screws.
  2. Choice depends on what network is available to you. If GPRS is still available, RAK13101 must be your choice. If you prefer NB-IoT or LTE-M, it should be RAK5860. If you want flexibility, it might be worth checking the RAK13102 which is based on BLUES.
  3. You must since the core is the brain of the whole system.
  4. I have no idea on the current consumption of pressure transducer. This is something you need to check. Also, we cannot say how much overall current you will use because it will highly depend on your code/firmware implementation as well.
3

Additional to Carl’s comment, for the supply of the 4-20mA sensor, if the supply for the sensor is 12V/50mA you can try the RAK19002 12V Boost module
This has the advantage that you can switch the supply on/off, which helps to reduce power consumption.