Hardware

Block Diagram

The following illustration demonstrates the team’s projected hardware system and how it interconnects with the centered microcontroller and ESP32 Module. Additionally, the team utilizes I2C as the core communication between our sensors and PIC module.

Component Selection Overview

Motor Subsystem

Motor Driver

DRV8830DGQR

Interface

I2C

Adafruit 5V Solenoid

Adafruit 4794

Supply

5V–6V

Max current

800 mA

Pololu 84 RPM 6V Micro Gearmotor

Pololu 3992

Supply

5V–6V

Max current

1200 mA

WhyWe decided to go with this particular product since we are able to get relatively higher torque in a small form factor with low power consumption. This fits our product idea well.

Temperature Sensor

Temperature Sensor

TC74A4-3.3VCTTR $0.97

Interface

I2C

Range

−40 °C to 125 °C

Supply

2.7V–5.5V

Max current

0.2 mA

WhyWhile the other options have a wider range of temperatures measure, this option was the best choice because it is the only option that is surface mount. Another reason is that we are familiar with this sensor from In-class assignments.

Product page →

Hall Effect Sensor (Wind Speed Subsystem)

Hall Effect Sensor

AS5600-ASOM $3.46

Interface

I2C

Supply

3.3V–5V

Max current

100 mA

WhyThis hall effect sensor will simplify the electrically design while only slightly increasing the programming difficulty. Despite needing to calculate linear velocity from rotational position, this sensor will greatly reduce materials cost in both pcb footprint and external construct.

Product page →

Microcontroller

Microcontroller

PIC18LF26K40-I/SO $2.04

Architecture

8-bit

Supply

1.8V–3.6V

GPIO

25 pins

Serial

I2C + SPI

WhyThis was chosen because it was the only one that is compatible with MCC and also it has more than enough pins than required. Additionally, it is the cheapest option out of the three and the voltage range is larger than the two other options.

Refer to Appendix E for more information

Hardware Implementation

The following is the schematic for our team PCB

Check Appendix H - Hardware Proposal for more information

PCB Renders

Team PCB

Daughter Board

Future Hardware Design Changes

In the development of our embedded systems project, it is crucial to carefully consider the power budgeting of the system. Our design currently relies on a wall power system but will need to rely on a standalone battery supply in our proposed application. With this said, It is imperative to evaluate ways in which power budgeting can be made more efficient. One approach that our team can consider, although slightly over the top, is the utilization of enable pins that can be controlled by unused pins from the microcontroller. Such power-saving techniques can extend the battery life of the system. Furthermore, more advanced methods, such as reducing power consumption during idle periods or implementing sleep modes, can also be explored.

Optimizing the hardware design is another important aspect to improve the performance and reliability of the system by utilizing more efficient hardware configurations. For instance, passive components packages (0805) can be standardized internally and avoid smaller IC packages as our motor controller was non-functional due to potential hardware issues with installation.

Leaving room for expansion and adaptability is an important quality to have when manufacturing. Additional sensors or hardware components can be easily added through connection pins and designing the software architecture to allow for easy modification. The potential for modularized sensor systems, such as atmospheric and humidity sensors, was discussed during the innovation showcase and should be considered for future development.

By taking into account these areas of improvement, our team can create a more efficient and reliable mobile weather station and the above changes can be implemented to ensure the system is adaptable for future versions.