ワイヤレスレーザーデータ通信（Li-Fi） - 100bps性能概要

必要な部品と材料

部品	数量	備考
Arduino Nano R3	2	送信側・受信側各1台
ブレッドボード（フルサイズ）	2
英数字LCD 16×2	2	送信側・受信側各1台
ジャンパーワイヤー	30本
キーパッド 4×3	1	送信側用
9V電池	2
9V電池スナップ	2
レーザーダイオード（2ピン）	1	送信側用
ソーラーセル（受光素子）	1	受信側用
可変抵抗器	2	LCDコントラスト調整用
抵抗 10kΩ	3

必要な工具

半田ごて
半田（鉛フリー推奨）

使用ソフトウェア・サービス

Arduino IDE

このプロジェクトについて

このプロジェクトは「送信機（エミッター）」と「受信機（レシーバー）」の2つで構成され、キーパッドで入力したテキストをレーザー光で飛ばし、受信側のLCDに表示します。可視光通信（Li-Fi）の基本原理を学べる優れた教材です。

コード

送信側コード（LI-FI Transmitter Code V 2.0）

/* LI-FI Transmitter Code V 2.0
   Written By HOUALEF AHMED RAMZI
   Started on 29-9-2020 Last Update on 14-10-2020 */
#define LaserPin 2
#include <LiquidCrystal.h>
const int rs = 12, en = 11, d4 = 6, d5 = 5, d6 = 4, d7 = 3;
LiquidCrystal lcd(rs, en, d4, d5, d6, d7);

int incomingchar;
int KeyPad_R[] = {A2, A1, 9, 7}; // キーパッド行ピン
int KeyPad_C[] = {8, 10, A3};    // キーパッド列ピン
int KeyReturn = 0;               // 押されたキー番号（1-12）
int ABC = 0;                     // 1ボタンで3文字入力用
int Row, Column;                 // キーパッドスキャン用
int StCursor = 0, NdCursor = 0;  // カーソル位置
int outcomingmatrix[32][5];      // 送信データバッファ
int m = 0;                       // バッファ有効長

// 5ビット符号化テーブル（A-Z, SPACE）
int A[] = {1,1,1,1,0}, B[] = {0,0,0,1,0}, C[] = {0,0,0,1,1}, D[] = {0,0,1,0,0},
    E[] = {0,0,1,0,1}, F[] = {0,0,1,1,0}, G[] = {0,0,1,1,1}, H[] = {0,1,0,0,0},
    I[] = {0,1,0,0,1}, J[] = {0,1,0,1,0}, K[] = {0,1,0,1,1}, L[] = {0,1,1,0,0},
    M[] = {0,1,1,0,1}, N[] = {0,1,1,1,0}, O[] = {0,1,1,1,1}, P[] = {1,0,0,0,0},
    Q[] = {1,0,0,0,1}, R[] = {1,0,0,1,0}, S[] = {1,0,0,1,1}, T[] = {1,0,1,0,0},
    U[] = {1,0,1,0,1}, V[] = {1,0,1,1,0}, W[] = {1,0,1,1,1}, X[] = {1,1,0,0,0},
    Y[] = {1,1,0,0,1}, Z[] = {1,1,0,1,0}, SPACE[] = {1,1,1,1,1};

void setup() {
  lcd.begin(16, 2);
  pinMode(LaserPin, OUTPUT);
  Serial.begin(9600);
  for(int i=0;i<4;i++) pinMode(KeyPad_R[i], OUTPUT);
  for(int j=0;j<3;j++) pinMode(KeyPad_C[j], INPUT);
  lcd.print("HOUALEF RAMZI");
  delay(5000);
  lcd.clear();
  lcd.setCursor(0,0);
}

void conv(int alpha[5], char Char) {
  for(int i=0;i<5;i++) outcomingmatrix[m][i] = alpha[i];
  lcd.print(Char);
}

void start_bit() {
  digitalWrite(LaserPin, HIGH);
  delay(9);
  digitalWrite(LaserPin, LOW);
}

void KeyPad() {
  for(int i=0;i<4;i++) {
    digitalWrite(KeyPad_R[i], HIGH);
    for(int j=0;j<3;j++) {
      if(digitalRead(KeyPad_C[j])==1) {
        Row=i; Column=j;
        digitalWrite(KeyPad_R[i], LOW);
        if(Row==0) { if(Column==0) KeyReturn=1; else if(Column==1) KeyReturn=2; else KeyReturn=3; }
        if(Row==1) { if(Column==0) KeyReturn=4; else if(Column==1) KeyReturn=5; else KeyReturn=6; }
        if(Row==2) { if(Column==0) KeyReturn=7; else if(Column==1) KeyReturn=8; else KeyReturn=9; }
        if(Row==3) { if(Column==0) KeyReturn=10; else if(Column==1) KeyReturn=11; else KeyReturn=12; }
      }
    }
  }
  Serial.println(KeyReturn);
}

void KeyToAscii(int KeyN, int FirtAsciiValue) {
  if(KeyReturn==KeyN) {
    incomingchar = FirtAsciiValue + ABC;
    ABC++; if(ABC==3) ABC=0;
  }
}

void CursorControler() {
  lcd.setCursor(StCursor, NdCursor);
  if(KeyReturn==10) { delay(100); StCursor++; m++; }
  if(StCursor==16) { StCursor=0; NdCursor=1; }
}

void loop() {
  KeyPad(); delay(150); CursorControler();
  KeyToAscii(1,65); KeyToAscii(2,68); KeyToAscii(3,71);
  KeyToAscii(4,74); KeyToAscii(5,77); KeyToAscii(6,80);
  KeyToAscii(7,83); KeyToAscii(8,86); KeyToAscii(9,89);
  KeyToAscii(11,32);

  switch(incomingchar) {
    case 65: conv(A,'A'); break; case 66: conv(B,'B'); break;
    case 67: conv(C,'C'); break; case 68: conv(D,'D'); break;
    case 69: conv(E,'E'); break; case 70: conv(F,'F'); break;
    case 71: conv(G,'G'); break; case 72: conv(H,'H'); break;
    case 73: conv(I,'I'); break; case 74: conv(J,'J'); break;
    case 75: conv(K,'K'); break; case 76: conv(L,'L'); break;
    case 77: conv(M,'M'); break; case 78: conv(N,'N'); break;
    case 79: conv(O,'O'); break; case 80: conv(P,'P'); break;
    case 81: conv(Q,'Q'); break; case 82: conv(R,'R'); break;
    case 83: conv(S,'S'); break; case 84: conv(T,'T'); break;
    case 85: conv(U,'U'); break; case 86: conv(V,'V'); break;
    case 87: conv(W,'W'); break; case 88: conv(X,'X'); break;
    case 89: conv(Y,'Y'); break; case 90: conv(Z,'Z'); break;
    case 32: conv(SPACE,' '); break; case 33: conv(SPACE,' '); break;
  }

  if(KeyReturn==12) { // 送信ボタン
    delay(100);
    for(int j=0;j<m;j++) {
      start_bit();
      for(int i=0;i<5;i++) { digitalWrite(LaserPin, outcomingmatrix[j][i]); delay(10); }
      digitalWrite(LaserPin, LOW); delay(20);
    }
    for(int k=0;k<32;k++) for(int l=0;l<5;l++) outcomingmatrix[k][l]=0;
  }
  incomingchar=0; KeyReturn=0;
}

受信側コード（LI-FI Receiver Code V 2.0）

/* LI-FI Receiver Code V 2.0
   Written By HOUALEF AHMED RAMZI
   Started on 29-9-2020 Last Update on 14-10-2020 */
#include <LiquidCrystal.h>
#define SolarCell A0
int StCursor = 0;
int A[] = {1,1,1,1,0}, B[] = {0,0,0,1,0}, C[] = {0,0,0,1,1}, D[] = {0,0,1,0,0},
    E[] = {0,0,1,0,1}, F[] = {0,0,1,1,0}, G[] = {0,0,1,1,1}, H[] = {0,1,0,0,0},
    I[] = {0,1,0,0,1}, J[] = {0,1,0,1,0}, K[] = {0,1,0,1,1}, L[] = {0,1,1,0,0},
    M[] = {0,1,1,0,1}, N[] = {0,1,1,1,0}, O[] = {0,1,1,1,1}, P[] = {1,0,0,0,0},
    Q[] = {1,0,0,0,1}, R[] = {1,0,0,1,0}, S[] = {1,0,0,1,1}, T[] = {1,0,1,0,0},
    U[] = {1,0,1,0,1}, V[] = {1,0,1,1,0}, W[] = {1,0,1,1,1}, X[] = {1,1,0,0,0},
    Y[] = {1,1,0,0,1}, Z[] = {1,1,0,1,0}, SPACE[] = {1,1,1,1,1};

const int rs=12, en=11, d4=5, d5=4, d6=3, d7=2;
int Cell_Input, Threshold, info[5];
LiquidCrystal lcd(rs, en, d4, d5, d6, d7);

void setup() {
  pinMode(A0, INPUT);
  Serial.begin(9600);
  lcd.begin(16,2);
  lcd.setCursor(0,0);
  Threshold = analogRead(SolarCell) + 10;
  lcd.print("READY TO RECEIVE");
  delay(5000);
  lcd.clear();
}

void BufferClear() { for(int i=0;i<5;i++) info[i]=0; }

void check_condition(int received[5], int ref[5], char c) {
  if(received[0]==ref[0] && received[1]==ref[1] && received[2]==ref[2] &&
     received[3]==ref[3] && received[4]==ref[4]) {
    lcd.print(c); CursorControler();
  }
}

void CursorControler() {
  StCursor++;
  if(StCursor==16) lcd.setCursor(0,1);
}

void loop() {
  Cell_Input = analogRead(SolarCell);
  if(Cell_Input > Threshold) { // スタートビット検出
    delay(10);
    for(int i=0;i<5;i++) {
      info[i] = (analogRead(SolarCell) > Threshold) ? 1 : 0;
      delay(10);
    }
    check_condition(info, A,'A'); check_condition(info, B,'B');
    check_condition(info, C,'C'); check_condition(info, D,'D');
    check_condition(info, E,'E'); check_condition(info, F,'F');
    check_condition(info, G,'G'); check_condition(info, H,'H');
    check_condition(info, I,'I'); check_condition(info, J,'J');
    check_condition(info, K,'K'); check_condition(info, L,'L');
    check_condition(info, M,'M'); check_condition(info, N,'N');
    check_condition(info, O,'O'); check_condition(info, P,'P');
    check_condition(info, Q,'Q'); check_condition(info, R,'R');
    check_condition(info, S,'S'); check_condition(info, T,'T');
    check_condition(info, U,'U'); check_condition(info, V,'V');
    check_condition(info, W,'W'); check_condition(info, X,'X');
    check_condition(info, Y,'Y'); check_condition(info, Z,'Z');
    check_condition(info, SPACE,' ');
    BufferClear();
  }
}