Weather station PCB

A small PCB capable of measuring pressure, humidity and temperature with LABview.

Introduction

During my third year I was tasked to develop a weather station online webserver using 3 simple sensors with LabVIEW and the ELVIS III. The sensors were chosen as a group but the task was individual, although it wasn't required, I felt the desire to make a custom PCB for the assignment to further improve my PCB designing, soldering and testing skills.

Sensors Selection

The sensors were selected based on a criteria created by the team:

Desired Unit
Measurement Range
Suitable Voltage
Linear or easy to read signals
ELVIS III compatibility
Documentation availability
Price

Because of the assignment constraints, funds and equipment available, a criteria had to be developed to help find a suitable sensor. Based on the criteria, suitable sensors were selected:

Pressure: SCCDANV015PAAA5
Temperature: TMP36
Humidity: HIH-4030

PCB Operation, Designing and Testing

Operation:

The weather station is operated by LabVIEW through the ELVIS III board by reading the sensor outputs through the analog and digital inputs. The LabVIEW back panel processes all these signals using signal conditioning which allows the raw data to be converted to useful and readable data such as Celsius or Pascals. The front panel displays this processed data in a user-friendly display. I designed both panels to provide the data in multiple formats, give visual warnings to the user based on changes in the atmosphere while also providing a simple weather prediction.

Back Panel Program

Front Panel Interface

PCB Design

The PCB consist of 3 sensors and 3 RGB LEDs for visual warnings based on atmospheric changes

Circuit Diagram on EASYEDA

When compared to previous PCBs it can clearly be seen that my circuit diagrams for PCBs improved, instead of using multiple lines to connect all inputs and outputs which can make the diagram confusing I instead learned and used tags which makes the diagram cleaner and simpler.

PCB Routing and design

3D PCB Model

Weather Station PCB

PCB with sensors, resistors and RGB LEDs installed

PCB Operating with LABview and ELVIS III

Finished Model

20230517_171329.mp4

Weather station in operation with LabVIEW

The RGB LED colours change based on different temperatures, pressure and humidity levels, in the video above the trigger values were modified to small differences, this was done to show the system and LEDs responding to the small readings from the sensors , but, with real world atmosphetic changes, the LEDs would slowly change colours over the course of hours or days.

Reflection

The PCB along with the sensors operated as expected providing accurate results but there are few things that could have been improved.

Sound warnings: Although there are RGB LEDs giving visual warnings based on the colour, the project could also benefit from audio warnings based on high or low temperature, pressure or humidity changes with the use of a buzzer.
PCB size: The PCB is too small making it difficult to connect cables as well as the sensors.
Case: the PCB could benefit from a protective case, keeping all connections insulated and sensors protected from damage.
Better weather station: The project could be expanded to a full weather station with more sensors, WI-FI data transmitting, rechargeable batteries, portable, weather resistant. These upgrades should allow the weather station to be placed outside 24/7 while providing accurate readings on a webserver.

The PCB also had a small mistake, all sensors positives were connected in series instead of parallel, meaning that the first sensor would operate fine but the subsequent ones in the series would not get enough current, however this was an easy fix by simply connecting another positive cable in parallel to the last sensor.

Parallel cable fix

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