Background:
Formula Student is the world most established educational engineering competition in which students from various universities compete to design, develop, build and race a formula type vehicle. These vehicles are high performance in terms of speed, braking and cornering. During the competition they are tested in static events i.e. design, cost and sustainability, business presentation and in dynamic contests which include acceleration, endurance, sprint, skid pad and fuel economy. The growing need to put into practice the skills taught in different courses of the Polytechnic of Leiria leaded students to invest in the Formula Student competition. The team (FSIPLeiria) has members from various areas of studies, from engineering students to management and marketing. For more information about the team visit our new website: https://www.fsipleiriaracing.com

Objective:

The main objective of the tyre temperature acquisition board, as its name suggests, is to measure the temperature of racing tyres. For that purpose, an infra-red sensor with 64 measure points (MLX90620) was used. The temperature data is sent to a microcontroller with a CAN transceiver that resends the required information to the CAN bus of the vehicle.

Supplies

• Temperature sensor MLX90620;

• Transceiver SPI-CAN MCP2515;

• Transceiver CAN MCP2551;

• Voltage regulator 12V-5V MCP1755_5;

• Voltage regulator 12V-3V MCP1755_3;

• Standalone Atmega328P microcontroller.

Step 1: Design

The main circuit of the vehicle works with a tension of approximately 12V. The board was built to operate with 5V, therefore, a voltage regulator (12V-5V) must be used. The temperature sensor's maximum tension is 3V so another voltage regulator (12V-3V) was used.
The data matrix (16x4) provided by the sensor's output is received and converted to 3 main tyre areas (inside, middle and outside). After that, the three variables are sent through SPI to a transceiver SPI-CAN MCP2515 that resends the information to the transceiver CAN MCP2551 which writes the variables in the vehicle's CAN bus.

Step 2: Prototyping

In order to check if everything worked as plan, before designing the PCB, the schematic was implemented on a breadboard. The figure does not show, but to simulate the 12V vehicle’s battery a power supply was used.
Note: Another device that reads CAN must be used to check if the CAN bus is working properly.

Step 3: PCB Design

The packaging of the components must be carefully planned because the module is going to be attached near the wheel so it should be as small as possible. The final result is shown in figure 3 and it as the following dimensions 48x12 mm.

Step 4: Ordering Your Pcb

JLCPCB offers fast, high-quality service at reasonable prices.
1. To order visit https://jlcpcb.com & sign in/sign up.

2. Click quote now button 3. Click on the “add your gerber file” button and upload your gerber files Now you can set your parameters and customizations, such as quantity and PCB colour;

4. Click “SAVE TO CART”;

5. Go ahead and type your shipping address, choose the shipping method;

6. Process to submit your order and payment;

7. The PCBs our team ordered came within the week.