List of materials

ESP8266 Board

Partlist

Exported from board_Laru_FIN.sch at 30.6.2020 18.25

EAGLE Version 9.5.2 Copyright (c) 1988-2019 Autodesk, Inc.

Assembly variant: 

Part        Value                   Device                          Package      Library   Sheet

3.3VIN      PINHD-2X2-SMD           PINHD-2X2-SMD                   2X02SMD      fab       1
C1          10uF                    CAP_UNPOLARIZEDFAB              C1206FAB     eagle_fab 1
C2          1uF                     CAP_UNPOLARIZEDFAB              C1206FAB     eagle_fab 1
FTDIVIN     SW_SLIDE-SWITCH         SW_SLIDE-SWITCH                 AYZ0102AGRLC eagle_fab 1
IC1         ESP-12E/F               ESP-12E/F                       ESP-12E      esp-12e-f 1
JP1                                 PINHD-2X3-SMD                   2X03SMD      fab       1
JP2                                 PINHD-2X3-SMD                   2X03SMD      fab       1
PROGRAMMODE SW_SLIDE-SWITCH         SW_SLIDE-SWITCH                 AYZ0102AGRLC eagle_fab 1
R1          10k                     R1206FAB                        R1206FAB     eagle_fab 1
R2          10k                     R1206FAB                        R1206FAB     eagle_fab 1
R3          12k                     R1206FAB                        R1206FAB     eagle_fab 1
R5          0                       RES-US1206FAB                   R1206FAB     fab       1
R6          0                       RES-US1206FAB                   R1206FAB     fab       1
RESET                               SW_SWITCH_TACTILE_6MM6MM_SWITCH 6MM_SWITCH   eagle_fab 1
U$4         CONN_06_FTDI-SMD-HEADER CONN_06_FTDI-SMD-HEADER         1X06SMD      eagle_fab 1
U1          VR_REGULATOR_SOT223     VR_REGULATOR_SOT223             SOT223       eagle_fab 1

Voltage step down board

Exported from stepdown_converter.sch at 30.6.2020 18.35

EAGLE Version 9.5.2 Copyright (c) 1988-2019 Autodesk, Inc.

Assembly variant: 

Part            Value          Device                     Package       Library             Sheet

0.1U5VCAP       CAP-US1206     CAP-US1206                 C1206         fab                 1
0.1UF3.3VCAP    CAP-US1206     CAP-US1206                 C1206         fab                 1
0.1UF3.3VCAPOUT CAP-US1206     CAP-US1206                 C1206         fab                 1
0.1UF5VCAP      CAP-US1206     CAP-US1206                 C1206         fab                 1
0.1UF5VCAPOUT   CAP-US1206     CAP-US1206                 C1206         fab                 1
0.1UF5VCAPOUT1  CAP-US1206     CAP-US1206                 C1206         fab                 1
3.3VCON                        CONN_03X22X3_SILK_MALE_PTH 2X3           SparkFun-Connectors 1
3.3VLED         LEDFAB1206     LEDFAB1206                 LED1206FAB    fab                 1
3.3VREG                        REGULATORSOT23             SOT23         fab                 1
3.3VREG1                       REGULATORSOT23             SOT23         fab                 1
5VCON                          CONN_03X22X3_SILK_MALE_PTH 2X3           SparkFun-Connectors 1
5VLED           LEDFAB1206     LEDFAB1206                 LED1206FAB    fab                 1
5VREG                          REGULATORSOT23             SOT23         fab                 1
6VIN                           CONN_02PTH3                1X02_LONGPADS SparkFun-Connectors 1
499POWERRES                    RES-US1206W                R1206W        fab                 1
2203.3V                        RES-US1206W                R1206W        fab                 1
4995V                          RES-US1206W                R1206W        fab                 1
>6VCON                         CONN_03X22X3_SILK_MALE_PTH 2X3           SparkFun-Connectors 1
POWERLED        LEDFAB1206     LEDFAB1206                 LED1206FAB    fab                 1
R3              0              RES-US1206FAB              R1206FAB      fab                 1

Motor controller: H-Bridge L293DD

			


Exported from MotorDriverLaru2020FabAcademy_VER_DD-hbridge.sch at 30.6.2020 18.41

EAGLE Version 9.5.2 Copyright (c) 1988-2019 Autodesk, Inc.

Assembly variant: 

Part     Value              Device             Package    Library             Sheet

5VDC     TERM-1X02-ADAFRUIT TERM-1X02-ADAFRUIT 3.5MMTERM  fab                 1
9-12VCC  TERM-1X02-ADAFRUIT TERM-1X02-ADAFRUIT 3.5MMTERM  fab                 1
ENABLE   TERM-1X02-ADAFRUIT TERM-1X02-ADAFRUIT 3.5MMTERM  fab                 1
IC1                         REGULATORSOT23     SOT23      fab                 1
IC3      L293DD             L293DD             SO20       st-microelectronics 1
INPUTA-B TERM-1X02-ADAFRUIT TERM-1X02-ADAFRUIT 3.5MMTERM  fab                 1
INPUTCD  TERM-1X02-ADAFRUIT TERM-1X02-ADAFRUIT 3.5MMTERM  fab                 1
MOTOR1   TERM-1X02-ADAFRUIT TERM-1X02-ADAFRUIT 3.5MMTERM  fab                 1
MOTOR2   TERM-1X02-ADAFRUIT TERM-1X02-ADAFRUIT 3.5MMTERM  fab                 1
R1       220                RES-US1206W        R1206W     fab                 1
R2                          RES-US1206W        R1206W     fab                 1
R3                          RES-US1206W        R1206W     fab                 1
R4                          RES-US1206W        R1206W     fab                 1
R5                          RES-US1206W        R1206W     fab                 1
R6       1K                 RES-US1206W        R1206W     fab                 1
U$1      LEDFAB1206         LEDFAB1206         LED1206FAB fab                 1
U$2      LEDFAB1206         LEDFAB1206         LED1206FAB fab                 1
U$3      LEDFAB1206         LEDFAB1206         LED1206FAB fab                 1
U$4      LEDFAB1206         LEDFAB1206         LED1206FAB fab                 1
U$5      LEDFAB1206         LEDFAB1206         LED1206FAB fab                 1
U$6      LEDFAB1206         LEDFAB1206         LED1206FAB fab                 1

Other components used

• Polulu minimotors x 2
• Cardboard 2x A3
• 9v Battery holder
• 1x 4x1,5v battery holder

To be developed (PRICES ARE MISSING ATM)

Desining and producing electronics

ESP8266 board

My design of ESP8266 board was derived from Neil's design of ESP-WROOM-02D board. The components used for this board include:

• ESP8266-12F Module
• 10k resistor x 2
• 12k resistor
• 1uF capacitor
• 10uF capacitor
• MOSFET SOT223 Regulator(3.3V)
• button switch (reset)
• slide switch (normal mode / program mode
• slide swithch (usb FTDI mode: regulator circuitry in use / 3,2V input from powerboard in use)
• 6-pin FTDI connector
• PINHD 2x2 connector (3,2VIN from powerboard in FTDI regulator isolation mode)
• PINHD-2X3 connector x 2 for GPIO connections

In this ESP8266 board schematics slide switch is used to choose between program and normal mode. In the program mode FTDI-cable connection can be used (after reset of the ESP8266) easily. When code is uploaded, then swich can be slided into normal mode.

This is done by pulling GPIO pins HIGH and LOW in certain order:

• Normal mode:GPIO pins GPIO0 and GPIO2 are HIGH and GPIO15 is low
• Program mode: GPIO0 is low, GPIO9 is low and GPIO2 is HIGH

So, these mode changes are done by slide switch in my design. In additon to that, I have wanted to add possibility to bypass 5v regulator in order to use 3,2Vinput from voltage step down board. So I added another slide switch to isolate it from other circuitry.

Motor controller board (H-Bridge)

H-Bridge (L293D) is very common chip for controlling DC-motors and stepper motors

You can see 4 input pins for L293D fir keft side, and pins 15 and 10 on the right side, as shown on the pin diagram below. Left input pins will regulate the rotation of motor connected across left side and right input for motor on the right hand side. The motors are rotated on the basis of the inputs provided across the input pins as LOGIC 0 or LOGIC 1. In simple you need to provide Logic 0 or 1 across the input pins for rotating the motor.

Lets consider a Motor connected on left side output pins (pin 3,6). For rotating the motor in clockwise direction the input pins has to be provided with Logic 1 and Logic 0.

						 
Pin 2 = Logic 1 and Pin 7 = Logic 0 | Clockwise Direction
Pin 2 = Logic 0 and Pin 7 = Logic 1 | Anticlockwise Direction
Pin 2 = Logic 0 and Pin 7 = Logic 0 | Idle [No rotation] [Hi-Impedance state]
Pin 2 = Logic 1 and Pin 7 = Logic 1 | Idle [No rotation]
				

In my design I used LEDs for debugging signals (power inputs and motor outputs

Voltage step down board

Voltage step down circuitry is needed because different components in the cardboard car consume different voltage levels:

• 3,2V ESP8266 VIN
• 5V L293D H-Bridge Motor controller Vcc (internal voltage 5v)
• 5V Servo (may be used in the second design spiral)
• 5V Ultrasonic sensor (may be used in the second design spiral)
• 7V or higher Polulu minimonotors

So, circuit was designed so, that highest voltage went straight trough to output pins. 5V voltage had one regulator and 3,2V voltage had one 5V regulator and one 3V regulator.

I used LEDs for debugging, to see that all connections work

Milling and soldering electronics

png-files were exported from the Eagle and then were used to create rml-files were done by using http://mods.cba.mit.edu/ -service

Then .rml-files were opened in user milling machine SRM-20 and board were milled

ESP2866 code

/********************************************************************
* This code needs Blynk app to be installed into phone              *
*                                                                   *
* Used Blynk widgets are: joystick for controls and Horizontal      *
* value display                                                     *
*                                                                   *
*  CC-BY-SA Jari Laru, Fab Academy 2020                             *
 ********************************************************************/



/* ESP2866 and Blynk Libraries are included */
#define BLYNK_PRINT Serial /* This library adds blynk spesific info to serial communication between Arduino IDE and board, can be removed after testing */
// #include  Servo Library is disabled, because I did simplify implementation and removed servo controlled precision steering. 
#include  /* ESP wifi Library */
#include  /* Blynk Library */

/* Pins for ultrasonic sensors are defined here */
#define TRIGGERPIN 1
#define ECHOPIN  3

/*  L293D motor enable pins are defined here */
int rightMotorEN = 14 ; /* GPIO14 -> Motor-A Enable  */
int leftMotorEN =  4 ;  /* GPIO12 -> Motor-B Enable */

/* L293D motor control pins are defined here */
int leftMotorForward = 13;     /* GPIO5 -> IN3   */
int rightMotorForward = 16;   /* GPIO4 -> IN1  */
int leftMotorBackward = 5;    /* GPIO10  -> IN4   */
int rightMotorBackward = 12;  /* GPIO9 -> IN2  */


/* Auth token for Blynk */
char auth[] = "SECRET-YOY-WILL-GET-THIS-FROM-BLYNK-PROJECT";

/* Local wifi network settings for Blynk. HOX! If you are running own server, then server and this client needs be in same SSID */
char ssid[] = "SSID";
char pass[] = "PASSWORD";

/* Local Blynk Server adress. It can be run also by using cloud service, but then amount free UX components is limited. 
 *  Own server has unlimited access.  In my case Rasperry Pi is server */

char server[] = "192.168.100.10";




// Reading ultrasonic sensor and sending readings to Blynk horizontal bar

BLYNK_READ(9) {

  long duration, distance;
  digitalWrite(TRIGGERPIN, LOW);  
  delayMicroseconds(3); 
  
  digitalWrite(TRIGGERPIN, HIGH);
  delayMicroseconds(12); 
  
  digitalWrite(TRIGGERPIN, LOW);
  duration = pulseIn(ECHOPIN, HIGH);
  distance = (duration/2) / 29.1;
  Serial.print(distance);
  Serial.println("Cm");

  Blynk.virtualWrite(9,distance);
}

// Handling Joystick data from Blynk and controlling left and right motors based on that
BLYNK_WRITE(V3){ 
int x = param[0].asInt(); 
int y = param[1].asInt();  

 // Do something with x and y
  Serial.print("X = ");
  Serial.print(x);
  Serial.print("; Y = ");
  Serial.println(y);

 if(y == 100)
 GoForward();  //Forward 
 
 else if(y == -100) 
 GoBackward(); //Backward  
 
 else if(x > 100) 
 TurnRight(); // Right turn

 else if(x < -100)  // Left turn
TurnLeft();
 
 else if (x == 0 && y == 0)
 Stop();
} 


// GO FORWARD //
void  GoForward(void)   
{
  Serial.println();
  Serial.print("Go to forward");
  analogWrite(leftMotorEN,255);
  analogWrite(rightMotorEN,255);
  digitalWrite(leftMotorForward,HIGH);
  digitalWrite(rightMotorForward,HIGH);
  digitalWrite(leftMotorBackward,LOW);
  digitalWrite(rightMotorBackward,LOW);
}

// Go backward //
void GoBackward(void)   
{
  Serial.println();
  Serial.print("Go to backward");
  analogWrite(leftMotorEN,255);
  analogWrite(rightMotorEN,255);
  digitalWrite(leftMotorBackward,HIGH);
  digitalWrite(rightMotorBackward,HIGH);
  digitalWrite(leftMotorForward,LOW);
  digitalWrite(rightMotorForward,LOW);
}

// TURN LEFT //
void TurnLeft(void)   
{
   Serial.println();
   Serial.print("turn to left");
  analogWrite(leftMotorEN,255);
  analogWrite(rightMotorEN,255); 
  digitalWrite(leftMotorForward,LOW);
  digitalWrite(rightMotorForward,HIGH);
  digitalWrite(rightMotorBackward,LOW);
  digitalWrite(leftMotorBackward,HIGH);  
}

// TURN RIGHT //
void TurnRight(void)   
{
  Serial.println();
  Serial.print("turn to right");
  analogWrite(leftMotorEN,255);
  analogWrite(rightMotorEN,255);
  digitalWrite(leftMotorForward,HIGH);
  digitalWrite(rightMotorForward,LOW);
  digitalWrite(rightMotorBackward,HIGH);
  digitalWrite(leftMotorBackward,LOW);
}

// STOP //
void Stop(void)   
{
  Serial.println();
  Serial.print("Stopped");
  analogWrite(leftMotorEN,0);
  analogWrite(rightMotorEN,0);
  digitalWrite(leftMotorForward,LOW);
  digitalWrite(leftMotorBackward,LOW);
  digitalWrite(rightMotorForward,LOW);
  digitalWrite(rightMotorBackward,LOW);
}


void setup() {

//********** CHANGE PIN FUNCTION  TO GPIO **********
//GPIO 1 (TX) swap the pin to a GPIO.
pinMode(1, FUNCTION_3); 
//GPIO 3 (RX) swap the pin to a GPIO.
pinMode(3, FUNCTION_3); 
//**************************************************


  /* motor control pins are here initialized as outputs */
  pinMode(leftMotorForward, OUTPUT);
  pinMode(rightMotorForward, OUTPUT); 
  pinMode(leftMotorBackward, OUTPUT);  
  pinMode(rightMotorBackward, OUTPUT);

  /* motor enable pins are initialized here as outputs */
  pinMode(leftMotorEN, OUTPUT); 
  pinMode(rightMotorEN, OUTPUT);

/* Ultrasonic sensor is initialized here: trigger as output and echo as input */
  pinMode(TRIGGERPIN, OUTPUT);
pinMode(ECHOPIN, INPUT);

/* Debug console is activated */
Serial.begin(115200); //debug console

/* Connection to Blynk server  is initialized */
// I did enable my local server connection, because I did work outside the home
Blynk.begin(auth, ssid, pass, server, 8080);

// I did disable Blynk cloud connection
//  Blynk.begin(auth, ssid, pass);
}


void loop() {
  /* run Blynk */

Blynk.run();

}