mopore / jni-proto-car-base

This is the firmware project to control the base microcontroller of the JNI Proto Car. This project rewrites the original CircuitPython code to C++ and uses the Arduino framework.

JNI Proto Car Base

This is the firmware project to control the base microcontroller of the JNI Proto Car. This project rewrites the original CircuitPython code to C++ and uses the Arduino framework.

A project for to control JNI Proto Car with a PS3 controller can be found here.

Features

Chassis and Motors

• Two driving (seperated) continious servo motors on front axis (FS90R).
• One servo motor for steering the rear axis (MG995R).
• Wooden chassis with custom soldered PCBs for motor control and MCU breakout.
• 4x1.5V AA batteries pack for motor power with switch on PCB.
• 1x3.7V 1100mAh battery for MCU power with separate switch.

Sensors and Connectivity

• Unexpected Maker Feather S3 Microcontroller (ESP32-S3) (https://unexpectedmaker.com/shop/feathers3)
• Distance sensor (VL53L4CX) for obstacle detection on the front.
• Accelerometer and Gyro sensor (ICM20649) for acceleration and tilt detection reading at 10Hz.
• OLED 128x64 display for debugging and status information.
• Direct Steering via UDP socker over Wifi at 100Hz
• MQTT connectivity (Currently only Alive tick w/ IP address)

MQTT Data and Topics

Alive tick on topic jniHome/services/jniProtoCar/alive with IP address as payload every 5 seconds.

Sensor data on topic jniHome/objects/jniProtoCar/events/sensors publishing at 1Hz. Example output:

		{
		"temperatureCelsius": 32.69317245,
		"accelX": 0.239420176,
		"accelY": -1.541865945,
		"accelZ": -9.959878922,
		"gyroX": 0.014899152,
		"gyroY": 0.00212845,
		"gyroZ": 0,
		"frontDistance": 765,
		"batVoltUnplug": 4.2
		}

Drive Assistance Features

Collission Avoidance

The forward movement is cut off if the front distance is lower than 20cm.

Steering Axis Protection

Any steering is cut off if no drive to the motors is requested.

Steering Friction

Reduces to rapid steering input.

Impressions

Overview

Display and Sensors

Front

Back

Underside

Sensor Data Visualitzation

Pre-requisites

• Fully setup platformIO environment
• An ESP32-S3 Microcontroller
• A Wifi network
• An MQTT broker (e.g. mosquitto)
• A ready-to-go JNI Proto car control unit (including connected PS3 contoller)

Setup

Create a include/jni_config.h file

For Wifi and further network setup. Create a file called include/jni_config.h with the following content:

#define SHOW_ENGINE_CONTROL_DEBUG 0

#define WIFI_SSID      "your-wifi-ssid"
#define WIFI_PASS      "your-wifi-password"

#define UDP_RECEIVER_SOCKET_PORT 8080

#define JNI_MQTT_BROKER_IP "192.168.100.219"
#define JNI_MQTT_BROKER_PORT 1883

Usage

• Turn on the MCU power switch and battery pack.
• Wait for the Wifi connection (OLED shows IP address).
• Check for an Alive message (every 5 seconds) on MQTT broker on topic jniHome/services/jniProtoCar/alive.
• Turn on the controller unit and hit the PS button to connect to control unit.
• Once the Bluetooth connection is established the UDP connection state between control unit and base changes to 'OK' (operational).