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EJA - Improvements in the Electronics Design

A project log for 2021 HDP Dream Team: EJA

Learn more about Team EJA's intelligent buoy, and how their solution will help the global fight against ghost gear.

Leonardo WardLeonardo Ward 10/20/2021 at 02:230 Comments

Since the beginning of this project we have designed and tested different electronic designs, this log compares them and highlights their features, cost and dimensions.

We recently design EJA M v1.0 with the goal of replacing the previous designs, including some features (and removing the unused ones), reducing the cost and the size of the design. This log will show if the new design accomplishes those goals.

The project contains 2 different products (the Intelligent Buoy and the Onboard Gateway), each one has a different application, this log will compare the PCB designs that have the same application.

Intelligent Buoy

This device provides communication, a GPS for localization and activates the Ropeless System. To create an Intelligent Buoy we have designed 3 different PCBs in the last 2 years, those are:

Features


Those designs include the following features:

FeaturesBuoy A v1.0Buoy B v1.0EJA M v1.0
LoRaXXX
GPSXXX
Servo MotorXXX
ESP32XXX
Real Time ClockXXX
DC MotorXX
4G (LTE)X
Battery ChargerX
Battery Level IndicatorX
AccelerometerX

Cost

Buoy A v1.0Buoy B v1.0EJA M v1.0
$201.01$131.02$108.39

The following logs contain the detailed bill of materials of each design.

Size

Buoy A v1.0 Buoy B v1.0EJA M v1.0
141.73 mm * 54.86 mm102.36 mm * 44.2 mm98 mm * 51 mm

Notes: Buoy A v1.0 and Buoy B v1.0 require a 5V input, therefore they require a module or a PCB that provides 5V from the battery, this module will increase the required space for the design. EJA M v1.0 contains the power supply module inside the design, it can be connected directly to a 3.7V battery (or battery pack).

Onboard Gateway

This devices allows the user to communicate with the intelligent buoys. To create an Onboard Gateway we have designed 2 different PCBs in the last 2 years, those are:

Features

Those designs include the following features:

FeaturesOnboard Gateway v1.0EJA M v1.0 (Reduced Version)
LoRaXX
ESP32XX
Battery ChargerXX
Real Time ClockX
Battery Level IndicatorX

The design EJA M v1.0 contains several features that are not present in the previous table, but they are not relevant for this application. In this comparison we are considering a reduce version of EJA M v1.0, it is basically the same PCB without the components that are not relevant in the application.

Cost

Onboard Gateway v1.0EJA M v1.0  (Reduced Version)
$84.34$76.07

The following logs contain the detailed bill of materials of each design.

Size

Onboard Gateway v1.0EJA M v1.0 (Reduced Version)
62.48 mm * 134.11 mm
98mm * 51 mm

Conclusion

For both applications, we can conclude that EJA M v1.0 is a better solution considering the metrics that have been presented in this log: features, cost and size.

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