Robotics Masters EduCar

The Robotics Masters EDUCar was part of the Crowd Supply Campaign in 2019. It provided a sensor kit that could be programed by kids. It uses the Robo HAT MM1 has the core controller for a varienty of educational programming challenges.

This guide will help you set up the car and get you started.

Parts Included

Bluetooth Serial Adaptor

The UART to Bluetooth Bridge Adaptor allows you to use your phone to control the car. The data rate is locked to 9600 baud. There are no drivers or additional software packages required for this adaptor to work. For the EduCar this part is linked with a number of free apps that allow you to send commands to the car over bluetooth from your phone.

Robo HAT	Bluetooth
GPS_TX	RXD
GPS_RX	TXD
5V	VCC
GND	GND

Example - CircuitPython

import board
import busio

# set up the bluetooth serial to uart device
bluetooth = busio.UART(board.TX, board.RX, baudrate=9600)

# read one byte
bluetooth.read(1)

# write bytes
bluetooth.write(b'Hello, World!')

Pressure Sensor

BMP280 is a popular pressure sensor module that supports both I2C and SPI operation. It sends back information to your program about the environment. It requires the Adafruit BMP280 CircuitPython driver to work.

Robo HAT	Pressure Sensor
3V3	VIN
GND	GND
SCL	SCK
SDA	SDI

NOTE: This sensor is 3V and the Robo HAT MM1 only provides 5V outputs. You may require a level shifter.

Example - CircuitPython

import board
import digitalio
import busio
import time
from adafruit_bmp280 import adafruit_bmp280

# Create library object using our Bus I2C port
i2c = busio.I2C(board.SCL, board.SDA)
bmp280 = adafruit_bmp280.Adafruit_BMP280_I2C(i2c)

# OR create library object using our Bus SPI port
#spi = busio.SPI(board.SCK, board.MOSI, board.MISO)
#bmp_cs = digitalio.DigitalInOut(board.D10)
#bmp280 = adafruit_bmp280.Adafruit_BMP280_SPI(spi, bmp_cs)

# change this to match the location's pressure (hPa) at sea level
bmp280.seaLevelhPa = 1013.25

while True:
    print("\nTemperature: %0.1f C" % bmp280.temperature)
    print("Pressure: %0.1f hPa" % bmp280.pressure)
    print("Altitude = %0.2f meters" % bmp280.altitude)
    time.sleep(2)

Ultrasonic Distance Sensor

The commonly used HC-SR04 Distance Sensor is used for measuring distances between 2 centimeters up to 4 meters. It sends out a 'sound pulse' and 'listens' for a response. It requires the Adafruit_CircuitPython_HCSR04 library to work.

Robo HAT	Distance Sensor
3V3	VCC
GND	GND
RCC1	Echo
RCC2	Trig

NOTE: This sensor is 3V and the Robo HAT MM1 only provides 5V outputs. Also be aware that the Robo HAT MM1 inputs are only 3V tolerable. You may require a level shifter.

Example - CircuitPython

import time
import board
import adafruit_hcsr04

sonar = adafruit_hcsr04.HCSR04(trigger_pin=board.RCC2, echo_pin=board.RCC1)

while True:
    try:
        print((sonar.distance,))
    except RuntimeError:
        print("Retrying!")
    time.sleep(0.1)

Motor Controller

The EduCar uses a Motor Controller to drive the two DC motors that come with the kit. The model provided with the kit is a TB6612FNG which is a commonly supplied part for powering small motors. This part works with the Robo HAT MM1 to drive the motors.

SparkFun Wiring Guide Datasheet

We have developed a custom CircuitPython Library for controlling the motors and encoders. It can be found here Robotics Masters Edu Car. Copy the file to the Robo HAT MM1 CIRCUITPY drive when you connect it via USB to your computer.

Example - CircuitPython

import board
import time
from robohateducar import *

car = RoboHatEduCar()

# drive the car forwards 1 metre
car.drive(RoboHatEduCar.CMD_DRV_FORWARD, 1)

# stop the car
car.stop()

Infrared Line Finder

This sensor allows the car to follow lines. It outputs digital signals that can be used to tell the car to change direction to stay on the line. It includes a 74HC14D shift register for keeping track of the state of all the infrared sensors.

Optical Rotary Encoder

MD-1358

Other Components

There are a number of other parts included

• Light Dependant Resistor
• Resistors
• Battery Holder
• Motors
• Solderless Breadboard