Onboard systems

Here you can find some general information about the onboard systems of the cars. More detailed information about the systems can be found in the car manual on Canvas. In the figures below the powertrain and system architectures can be seen.

Control box

Here the modules that are inside of the control box are explained.

PYNQ Z2 board

This is the the board that can be programmed by students.

EPE control board

This board is based on the ESP32-S3 system-on-chip. It is used for UART interface with the PYNQ and for collecting important data. It also provides a WiFi-hotspot named "5EWC0_CAR_xx_yyyyyy" to which students can connect using the password "5EWC0_CAR_xx" where xx is the number of the car. After connecting to the hotspot the web portal http://192.168.4.1 can be accessed. In the website energy, speed, throttle and other data can be seen and monitored.

nRF24 radio transceiver

This a radio transeiver module which is used to implement the toll booth capability of the car. The module should send the course code "5EWC0" together with the car number when the IR sensor detects the toll booth. The nRF24L01+ transceiver uses the SPI communication functionality of the PYNQ. Rather than code SPI communication, a library is available with pre-made functions to operate it.

IR receiver

The IR receiver is used to detect the toll booth. The circuit has to be assembled by students themselves. The circuit diagram of the reciever can be seen in the figure below.

RPM sensor

A Futuba SBS-01RM RPM sensor is mounted on the model car to measure the speed of the model car. The RPM sensor is mounted in front of a cogwheel that is driven by the electric motor (Note: gear ratio must be included in your speed calculations). Two magnets are mounted in the cogwheel. The output of the RPM sensor becomes high (voltage) when the magnet passes the RPM sensor.

LED bars

There are four RGB LED bars each mounted on one of the four sides of the car. Each bar has 32 RGB-LEDs. They should be used to show the driver when the optimal velocity is reached. Each strip has three pins, clock (CLK), serial data in (SDI) and latch enable (LE). A bit is sent to the LED strip by first setting SDI to the desired level (HIGH/LOW) and then pulling the CLK pin high. This way each color component of an individual RGB LED can be set. Then this has to be repeated 31 more times for the remaining LEDs on the bar. Finally the data is latched by pulling the LE pin high. This has to be done for each LED bar separately. This way each individual LED on all of the bars can be controlled. Detailed diagram and signal timing info can be found in the car manual.