Chasiss Design

Sonar Viz Bot v1

7/16/25

Chassis

Chassis & Mounting Layout

• Use a caliper to take measurements
  • Chassis: 20.5 cm x 13.0 cm x 5.5 cm
• Draw Sketch

Measurements

• Chassis: 20.5 cm x 13.0 cm x 5.5 cm

Sketch

CAD (Solidworks)

Tinkercad design (Chloe)

https://www.tinkercad.com/things/lr8VxS2y9I1/edit?returnTo=%2Fdashboard&sharecode=GgRsnzei7CGlOPf53LRodDr3RVC0fpdu-eLudGKORLk

Updated assembly

Caster wheel

5/8 in. Roller Ball Bearing

Screws

8-32 x 1-1/4 in. Zinc Plated Combo Truss Head Machine Screw

Part	Meaning
#8	Screw size (diameter) — approximately 0.164 inches (4.17 mm)
32	Thread pitch — 32 threads per inch (TPI)
1-1/4 in.	Length — the screw is 1.25 inches (31.75 mm) long from head to tip (or from under the head if it’s a flat head)

Caster wheel mounting holes

• Draw construction rectangle for caster’s mounting plate holes

• Draw circles with centers coincident with the rectangle corners
  • Clearance hole for screw pass through: 0.17 mm (4.32 in)

• Cut-Extrude

Motor wheel assembly

Gearbox motor

https://a.co/d/ahxAD8G

Shaft Extension

Pass through holes

• Make holes for DC motor shaft

3D Print

Prep

• Go to File → Save As → Choose STL

Caster Wheel mount/adapter

• Draw a 6cm x 6cm square and extrude 2cm

• Extude cut through block

• Change the radius for one hole to 0.3cm to allow ball caster to be screwed on

• Use Insert → Features → Save Bodies to save just the mounting block

Electrical Setup

Arduino Nano BLE

Warning- Arduino Nano 33 BLE operates on 3.3V

• The Nano’s 3.3V output may be enough to for the L298D logic pins, but not the VCC pins
• Never input 5V signals into the Nano BLE

L293D Motor Driver

• Set up L293D Motor Driver circuit

Wiring

L293D Pin Name	L293D Pin Number	Nano Pin	Function
EN1	1	11 (ENA)	Right motor speed (PWM)
IN1	2	13 (IN1)	Right motor direction 1
IN2	7	12 (IN2)	Right motor direction 2
IN3	10	8 (IN3)	Left motor direction 1
IN4	15	9 (IN4)	Left motor direction 2
EN2	9	10 (ENB)	Left motor speed (PWM)
GND	12	GND	Ground

Code

L293D_motor_driver_nano.ino

// L293D Motor Driver pins for right motor (Motor A)
const int ENA = 11;    // PWM speed control for right motor
const int IN1 = 13;    // Direction control 1 for right motor
const int IN2 = 12;    // Direction control 2 for right motor
 
// L293D Motor Driver pins for left motor (Motor B)
const int ENB = 10;    // PWM speed control for left motor
const int IN3 = 8;     // Direction control 1 for left motor
const int IN4 = 9;     // Direction control 2 for left motor
 
const int switchPin = 7; // Switch to turn robot on/off
 
int motorSpeed = 0; // Starting motor speed
 
void setup() {
    pinMode(switchPin, INPUT_PULLUP);
 
    pinMode(IN1, OUTPUT);
    pinMode(IN2, OUTPUT);
    pinMode(ENA, OUTPUT);
 
    pinMode(IN3, OUTPUT);
    pinMode(IN4, OUTPUT);
    pinMode(ENB, OUTPUT);
 
    Serial.begin(9600);
    Serial.println("To infinity and beyond!");
    motorSpeed = 255;
    Serial.print("Motor Speed: ");
    Serial.println(motorSpeed);
}
 
void loop() {
    motorSpeed = 255;
    // if (digitalRead(switchPin) == LOW) { // Switch ON (pressed)
    if (digitalRead(switchPin) == HIGH) { // Switch OFF 
        rightMotor(motorSpeed);
        leftMotor(motorSpeed);
    } else { // Switch OFF
        rightMotor(0);
        leftMotor(0);
    }
}
 
void rightMotor(int speed) {
    if (speed > 0) {
        digitalWrite(IN1, HIGH);
        digitalWrite(IN2, LOW);
    } else if (speed < 0) {
        digitalWrite(IN1, LOW);
        digitalWrite(IN2, HIGH);
    } else {
        digitalWrite(IN1, LOW);
        digitalWrite(IN2, LOW);
    }
    analogWrite(ENA, abs(speed));
}
 
void leftMotor(int speed) {
    if (speed > 0) {
        digitalWrite(IN3, HIGH);
        digitalWrite(IN4, LOW);
    } else if (speed < 0) {
        digitalWrite(IN3, LOW);
        digitalWrite(IN4, HIGH);
    } else {
        digitalWrite(IN3, LOW);
        digitalWrite(IN4, LOW);
    }
    analogWrite(ENB, abs(speed));
}

Battery pack

Elegoo Switched Battery Pack Voltage?

• dimensions: 4” x 2” x 1”
• nominal voltage: 7.7V
• max charge voltage 8.4v

Make Assembly

Wheel

• diameter: 6cm

Wheel - 65mm (Rubber Tire, Pair)

These are a pair of basic, 65mm wheels with black rubber tires. These wheels are the same ones designed to fit onto DAGUs right angle gear motors utilized in the Magician Chassis and RedBot Kit. With these wheels you will be able to get almost any beginners robot project moving.

Grabcad- 65mm Rubber Wheel.SLDPT

Hobby Gear Motor

https://cad.onshape.com/documents/3304df14f1047a5cdcc9ee94/w/2e91bdd099aa410aa079012b/e/f62da644dddc7a47f10d5392

Caster wheel

Screws

TRUSS HEAD SCREW

Assembly

Exploded View