Baja sensor network developed to Bombaja UFSM.
Baja SAE is a project developed by Automotive Engineering Society and has as main objective that engineering students could apply on real life the knowledge acquired in universities and colleges classes. The engineering students must design and build a mini baja prototype that attends the contest requirements and statute, given by SAE.
The competition have different phases, one theroretical, when the students have to write a project report and present their car projects to contest judges (graduated engineers) and one practical, when the car is evaluated in different exams, each one aimed to stress one or more specific car parts.
The last competition test is an endurance, basically a resistance race, where the car that executes more laps in the circuit during 3 hours wins the race.
The competition circuit have a lot of obstacles, like tree trunks and big stones, and its objective is to break the car.
Baja SAE competition is an endurance project and the students vehicles need to be prepared to overdue any obstacle.
Bombaja UFSM is the team that carries Federal University of Santa Maria name.
The objective of this project is to develop a sensor network to monitor the prototype in real time.
Use embedded electronical in this kind of vehicle is one of the most hard tasks for electrical engineerings because the enviroment is completely inhospitable, and the system needs to bear impacts, dust, water, mud and clay.
The microcotroller used in project is a XMEGA2560.
The Mega 2560 is a microcontroller based on the ATmega2560. It has 54 digital input/output pins (of which 15 can be used as PWM outputs), 16 analog inputs, 4 UARTs (hardware serial ports), a 16 MHz crystal oscillator, a USB connection, a power jack, an ICSP header, and a reset button.
It was used Arduino IDE to develop software.
It was chose Arduino platform because it has a big community, it is cheap and open source.
The main project have the following sensors:
- Fuel level sensor
- Temperature sensor
- Velocity sensor
- Motor Revolution per Minute (RPM) sensor
In addition, it has a Real Time Clock (RTC), a Standard Drive (SD) card to record monitored data and a Graphical Liquid Crystal Display (GLCD) fixed in the steering wheel to made the information visible to the car pilot.
The RTC gives the TimeStamp, and provides its information on GLCD screen.
The SD card receives car real time information every 2 seconds.
The Fuel Sensor is a capacitive sensor and it monitors the fuel level in prototype's fuel tank.
The velocity and RPM sensors are inductive sensors that detects pulses and send it to the microcontroller.
The pilot can view two different screens in GLCD, swaped using a "Swap Screen" button, in the steering wheel.
In the first screen it is shown Gearbox temperature, Velocity and motor RPM.
In the second screen it is show the Timestamp and Fuel Tank status.
One new idea is to use two Radio Frequency (RF) modules to send the monitored data to another microcontroller situated in team pit stop place.
The RF module needs to send information in equal time invervals, the same time when it is stored information in SD card.
Its main goal is grant car physical measures acess to the whole team in real time, facilitating the process of fault detection and problem correction.
To improve inductive sensors (RPM + velocity) reliability it is used system interruption to acquire sensor data.
In addition, it is calculated an average every 10 times acquisition, to enhance precision.
The capacitive sensor is positioned in the fuel tank half bottom part, assuring the detection of low fuel. To improve the sensor measure, after it detects the fuel fault, it enables a timer that is reseted if it is detected another signal of fuel presence. This way, only if the sensor detects fuel fault during 20 consecutive seconds, the GLCD shows "Empty Fuel" warning. This detection system using a timer avoids fake detections.
The temperatue is measured using a Type K Thermocouple, that is tied in in the gearbox. To read its signal with perfection it is used an AD595 integrated circuit, responsible for Cold Junction Compensation and precision improvement. After this singal conditioning, the temperature is sended via analog ports to microcontroller.
##Future Modifications To enchance car embedded system it is being developed the same software using a different and better hardware architecture, with a better IDE, like Texas Instruments MSP430 board and Code Composer Studio or Freescale FRDM K-22F with Kinetis Design Studio and a Cortex ARM chip.
Moreover, the thermocouple, inductive and capacitive sensors will be swaped by automotive sensors.
To improve pilot visibility while driving it will be developed an analogic automotive panel to show RPM + Velocity.
The prototype electhroncical system counts too with a LED headlight pair and a horn.
The whole system is protected by a 1A fuse and powered by a 1000mAh Zippy battery, used mainly in aeromodelling projects. ;)
This prototype is called BJ-14 and was developed during 2016 by Bombaja UFSM, Federal University of Santa Maria Baja Team. The following pictures were been taken durigin Brazilian South Baja competition, accomplished from 18 to 20 November 2016, in Passo Fundo - RS.
BJ-14 Bombaja Prototype:
BJ-14 ECU:
BJ-14 ECU in Place:
BJ-14 ECU (all connected):
BJ-14 ECU (closed):
BJ-14 RPM Sensor:
BJ-14 Velocity Sensor:
BJ-14 Fuel Sensor:
BJ-14 Rear View (the thermocouple can be seen tied in gearbox):
Baja SAE is a competition and for a 2 years this was Bombaja UFSM embedded system project.
Furthermore, this project was placed in 3rd during "2015 National Baja SAE Competition" and "2016 Baja South Competition" in the category: "Embedded System Design Exam".
However, it is now open source and available to another teams, car enthusiasts and engineers to see the project and take some ideas for develop their own designs.
Today, the prototype is being developed using improved sensors and diferent hardware architecture.
The project can be reproduced with no problem.
However, I only ask you to mantain original credits/references to the author.
Enjoy!
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