Reforming a Small Electric Fan

Summer is coming with steadily increasing warmth. Now, it is a right time to prepare a summer thing ─ a fanner! Therefore, I have bought a small fanner online; it is good except that it cannot steering.

However, is this a problem? No! As a creative engineer, it’s show time!

Looks cute, doesn’t it? Click the video below for more details of the reforming.

Hardware:

FireBeetle ESP32 IoT microcontroller (supports Wi-Fi & Bluetooth) × 1

FireBeetle Covers-Gravity I/O Expansion Shield× 1

Gravity: I2C OLED-2864 display × 1

BME temperature-humidity sensor × 1

EC11J rotary encoder × 1

9g micro servo (1.6kg) (SKU: SER0006) × 1

Dupont line × 10

Crust by overlord 3D printer × 1

*No need for soldering during the whole working process.

Hardware Connection

Connect I2C interface of OLED12864 directly to I2C interface of Gravity Expansion shield, and connect A of EC11J rotary encoder to D0, B to D1, C to D8. Then connect the micro servo to D3 and connect SPI interface of BME280 directly to SPI interface of Gravity Expansion shield, CS (Chip Select) to D5.

The circuit diagram is as shown below:

Working Process

- Print the crust with 3D printer.

Click here to download the program and the source code for 3D printing.

- Fix the rotary encoder to the crust.

- Fix OLED2864 to the crust.

Connect OLED display to Gravity board with Dupont and the connection interface is I2C.

- Connect BME280.

BME280 uses SPI interface, please refer to the previous circuit diagram for details of connection.

- Allocate the fan.

Remove the lithium battery and connect the power supply of the fan to Vcc and GND of FireBeetle ESP8266, edge connecting the lithium battery to FireBeetle ESP8266. Then set connect the micro servo to D3.

- Complete machine assembly.

Cover the bottom and fix it with hot-melt glue, and download the program.

#include <Wire.h>  // Only needed for Arduino 1.6.5 and earlier
#include <Servo.h> 
#include "SSD1306.h" // alias for `#include "SSD1306Wire.h"`
#include "OLEDDisplayUi.h"
#include "images.h"
#include <DFRobot_BME280.h>
#include <SimpleTimer.h>
#define SEA_LEVEL_PRESSURE  1013.25f
#define BME_CS D5
SimpleTimer timer;
int timeCounter = 0;
boolean uiEnable = true;
DFRobot_BME280 bme(BME_CS); //SPI
SSD1306  display(0x3c, D7, D6);
Servo  mymotor;  
OLEDDisplayUi ui( &display );
enum model{
 MODEL_NULL,
 MODEL_LEFT,
 MODEL_RIGHT,
 MODEL_BUTTON
};
enum setFrame{
 SET_NULL,
 SET_FRAME_2_ON,
 SET_FRAME_2_OFF,
 SET_FRAME_3_ON,
 SET_FRAME_3_OFF
};
enum motorModel{
 MOTOR_AUTO,
 MOTOR_STATIC
};
char commondModel = MODEL_NULL;
char setFrameValue = SET_NULL;
char motorState = MOTOR_STATIC;
int encoderPinA = D0;
int encoderPinB = D1;
int buttonPin = D8;
volatile int lastEncoded = 0;
volatile long encoderValue = 0;
long lastencoderValue = 0;
int lastMSB = 0;
int lastLSB = 0;
int speedValue = 5;
int angleValue = 90;
boolean dir = true;
int frameIndex = 0;
long readEncoderValue(void){
   return encoderValue/4;
}
boolean isButtonPushDown(void){
 if(!digitalRead(buttonPin)){
   delay(5);
   if(!digitalRead(buttonPin)){
     while(!digitalRead(buttonPin));
     return true;
   }
 }
 return false;
}
void msOverlay(OLEDDisplay *display, OLEDDisplayUiState* state) {
 if(frameIndex == 0)
   return;
 display->setTextAlignment(TEXT_ALIGN_RIGHT);
 display->setFont(ArialMT_Plain_10);
 display->drawString(128, 0, String(angleValue));
}
void drawFrame1(OLEDDisplay *display, OLEDDisplayUiState* state, int16_t x, int16_t y) {
 display->setTextAlignment(TEXT_ALIGN_LEFT);
 display->setFont(ArialMT_Plain_24);
 display->drawString(15 + x, 10+ y, "ChoCho");
}
void drawFrame2(OLEDDisplay *display, OLEDDisplayUiState* state, int16_t x, int16_t y) {
 float temp = bme.temperatureValue();
 float pa = bme.pressureValue();
 float hum = bme.altitudeValue(SEA_LEVEL_PRESSURE);
 float alt = bme.humidityValue();
 // Demonstrates the 3 included default sizes. The fonts come from SSD1306Fonts.h file
 // Besides the default fonts there will be a program to convert TrueType fonts into this format
 display->setTextAlignment(TEXT_ALIGN_LEFT);
 display->setFont(ArialMT_Plain_16);
 display->drawString(x, y,String("Temp: ")+String(temp));
 display->drawString(x, 17 + y, String("Hum:  ")+String(alt));
 display->drawString(x, 34 + y, String("Pa:   ")+String(pa));
}
void drawFrame3(OLEDDisplay *display, OLEDDisplayUiState* state, int16_t x, int16_t y) {
 // Text alignment demo
 display->setFont(ArialMT_Plain_16);
 // The coordinates define the left starting point of the text
 display->setTextAlignment(TEXT_ALIGN_LEFT);
 display->drawString(x,  y, "Set Speed");
 display->drawString(40+x, y+17,String(speedValue));
}
void drawFrame4(OLEDDisplay *display, OLEDDisplayUiState* state, int16_t x, int16_t y) {
 // Text alignment demo
 display->setFont(ArialMT_Plain_16);
 // The coordinates define the left starting point of the text
 display->setTextAlignment(TEXT_ALIGN_LEFT);
 display->drawString(x,  y, "FAN Model");
 if(motorState == MOTOR_STATIC){
   display->drawString(40+x, y+27,"STATIC");
 }else if(motorState == MOTOR_AUTO){
   display->drawString(40+x, y+27,"AUTO");
 }
}
// This array keeps function pointers to all frames
// frames are the single views that slide in
FrameCallback frames[] = { drawFrame1, drawFrame2, drawFrame3, drawFrame4};
// how many frames are there?
int frameCount = 4;
// Overlays are statically drawn on top of a frame eg. a clock
OverlayCallback overlays[] = { msOverlay };
int overlaysCount = 1;
void ec11Init(void){
 pinMode(encoderPinA, INPUT); 
 pinMode(encoderPinB, INPUT);
 pinMode(buttonPin, INPUT);
 digitalWrite(encoderPinA, HIGH); //turn pullup resistor on
 digitalWrite(encoderPinB, HIGH); //turn pullup resistor on
 attachInterrupt(D0, updateEncoder, CHANGE); 
 attachInterrupt(D1, updateEncoder, CHANGE);
}
void displayInit(void){
 ui.setTargetFPS(60);
 ui.setActiveSymbol(activeSymbol);
 ui.setInactiveSymbol(inactiveSymbol);
 ui.setIndicatorPosition(BOTTOM);
 ui.setIndicatorDirection(LEFT_RIGHT);
 ui.setFrameAnimation(SLIDE_LEFT);
 ui.setFrames(frames, frameCount);
 ui.setOverlays(overlays, overlaysCount);
 ui.disableAutoTransition();
 ui.switchToFrame(frameIndex);
 ui.init();
 display.flipScreenVertically();
}
void motorInit(void){
 mymotor.attach(D3);
 mymotor.write(speedValue);
}
void updateUi(void){
 if(timeCounter>50){
   display.displayOff();
   uiEnable = false;
 }else{
   display.displayOn();
   uiEnable = true;
   timeCounter++;
 }
 if(commondModel == MODEL_RIGHT){
   frameIndex++;
   if(frameIndex > 3)
     frameIndex = 0;
   ui.switchToFrame(frameIndex);
 }else if(commondModel == MODEL_LEFT){
   frameIndex--;
   if(frameIndex < 0)
     frameIndex = 3;
   ui.switchToFrame(frameIndex);
 }
 commondModel = MODEL_NULL;
}
void updateMotor(void){
 if(motorState == MOTOR_AUTO){
  if(dir == true){
   angleValue += speedValue;
  }else{
   angleValue -= speedValue;
  }
 }
  if(angleValue > 180)
   dir = false;
  else if(angleValue < 0)
   dir = true;
  mymotor.write(angleValue);
}
void doButton(void){
 if(isButtonPushDown()){
   if(uiEnable == false){
     commondModel = MODEL_NULL;
   }else{
     commondModel = MODEL_BUTTON;
   }
   timeCounter = 0;
 }
 if(readEncoderValue()!=0){
   long value = readEncoderValue();
   if(uiEnable == true){
     if(value > 0){
       commondModel = MODEL_RIGHT;
     }else{
       commondModel = MODEL_LEFT;
     }
   }
   timeCounter = 0;
   encoderValue = 0;
 }
 if(frameIndex == 2){
   if(commondModel == MODEL_BUTTON){
     if(setFrameValue == SET_FRAME_2_ON){
       setFrameValue = SET_FRAME_2_OFF;
     }else{
       setFrameValue = SET_FRAME_2_ON;
     }
     commondModel = MODEL_NULL;
   }
   if(setFrameValue == SET_FRAME_2_ON){
     if(commondModel == MODEL_RIGHT){
       speedValue++;
     }else if((commondModel == MODEL_LEFT)){
       speedValue--;
     }
     if(speedValue > 20)
      speedValue = 20;
     if(speedValue < 0)
      speedValue = 0;
      commondModel = MODEL_NULL;
   }
 }
  if(frameIndex == 3){
   if(commondModel == MODEL_BUTTON){
     if(setFrameValue == SET_FRAME_3_ON){
       setFrameValue = SET_FRAME_3_OFF;
     }else{
       setFrameValue = SET_FRAME_3_ON;
     }
     commondModel = MODEL_NULL;
   }
   if(setFrameValue == SET_FRAME_3_ON){
     if((commondModel == MODEL_RIGHT) || (commondModel == MODEL_LEFT)){
       motorState = (motorState==MOTOR_AUTO)?MOTOR_STATIC:MOTOR_AUTO;
     }
     commondModel = MODEL_NULL;
   }
 }
}
void setup() {
 ec11Init();
 displayInit();
 motorInit();
 bme.begin();     
 timer.setInterval(200,updateUi);
 timer.setInterval(50,updateMotor);
}
void loop(){
 int remainingTimeBudget = ui.update();
 if (remainingTimeBudget > 0) {
   delay(remainingTimeBudget);
 }
 doButton();
 timer.run();
}
void updateEncoder(){
 int MSB = digitalRead(encoderPinA); //MSB = most significant bit
 int LSB = digitalRead(encoderPinB); //LSB = least significant bit
 int encoded = (MSB << 1) |LSB; //converting the 2 pin value to single number
 int sum  = (lastEncoded << 2) | encoded; //adding it to the previous encoded value
 if(sum == 0b1101 || sum == 0b0100 || sum == 0b0010 || sum == 0b1011) encoderValue ++;
 if(sum == 0b1110 || sum == 0b0111 || sum == 0b0001 || sum == 0b1000) encoderValue --;
 if(uiEnable == false)
   encoderValue = 0;
 lastEncoded = encoded; //store this value for next time
}

Well done!