To feed my passion, personally I have built a WiFi data logger prototype for industrial application. It was a good learning on technical as well as product development front.

I have executed the following  activities.

Component selection, Hardware design, Schematic, Board bring-up and development of firmware for application micro-controller, WIFI controller & Web service used to store the data to the Microsoft SQL database on Microsoft Azure cloud.

The PCB design is done by  a Freelancer and I have outsourced a PCB manufacturing and component assembly to a local vendor.

Some of the key features of this board includes

  • On board DC-DC buck converter and 3.3v LDO for powering WiFi
  • ESP8266 for WIFI connectivity. 
  • Atmega328p application micro-controller
  • Non Isolated Rs485 Modbus with jumper for terminal resistor.
  • 8 digital input
  • 2 status LEDs and 1 power led.
  • AVR-ISP connector for debugging
  • Possibility to reset WIFI chip from application micro-controller.

Some of the software feature to mention are 

  • Time synchronization of client(data loggers) based on server tome.( about 50ms accuracy.)
  • Buffer the data records to cope with intermittent connection issues to the server. 
  • Identify the connection issue to the gateway and to the server and execute recovery procedure. 
  • Digital data acquisition.
  • Implementation of Modbus Slave.

Test results

The test results on the lab bench is encouraging and works as expected.

However on harsh industrial environment (electro-plating factory) with several SMPS based rectifies and industrial motor drives, the device had several resets per hour during the field trial.