Saving an Array in the Mysql database - Laravel

Question

I’m a beginner in the Laravel framework and I’m in need of some help. I need to save an array in the Mysql database, however it is generating the following message.

Errorexception in Diariocontroller.php line 334: Illegal string offset 'presenca_id

When I debug my values, I see that I am receiving, but I cannot enter in the database as per image.

Below follows source code.

Controller

public function salvar_lista_de_presenca(Request $request, $id, $presenca_id)
   {
      $presencas = DB::table('turma_alunos')
      ->join('turmas', 'turmas.id', '=', 'turma_alunos.turma_id')
      ->join('alunos', 'alunos.id', '=', 'turma_alunos.aluno_id')
      ->join('tur_prof_discs', 'tur_prof_discs.turma_id','=', 'turmas.id')
      ->join('diarios', 'diarios.tur_prof_discs_id', '=', 'tur_prof_discs.id')
      ->join('presencas', 'presencas.diario_id', '=', 'diarios.id')
      ->select('turma_alunos.*', 'alunos.id as alu_id', 'alunos.matricula as alu_mat', 'alunos.nome as alu_nome',
      'diarios.id as dia_id', 'presencas.id as pre_id')
      ->where('presencas.id', $presenca_id)
      ->get();

      $dados = $request->all();
      //dd($dados);
      foreach ($dados as $d) {
         $registro = new AlunoPresenca();

         $registro->presenca_id =  $d['presenca_id'];
         $registro->presenca = $d['presenca'];
         $registro->aluno_id = $d['aluno_id'];

         $registro->save();
      }

      \Session::flash('mensagem',['msg'=>'Registro criado com sucesso!','class'=>'green white-text']);

      return redirect()->route('admin.galerias', $imovel->id);

   }

View

<form action="{{ route('admin.diario_online.salvar_lista_de_presenca', [$tpd, $diario]) }}" method="post">
   {{ csrf_field() }}
   <button class="btn waves-effect waves-light blue">
      Adicionar
      <i class="material-icons right">add</i>
   </button>

   <div class="row col s12 m12">
      <table class="bordered highlight responsive-table centered">
         <thead>
            <tr>
               <th></th>
               <th>Matricula</th>
               <th>Aluno</th>
               <th>Status</th>
               <th></th>
            </tr>
         </thead>
         <tbody>
            @foreach ($presencas as $presenca)
               <tr>
                  <td>
                     <div class="input-field">
                        <input type="hidden" name="presenca_id[]" value="{{ $presenca->pre_id }}">
                     </div>
                  </td>
                  <td>{{ $presenca->alu_mat }}</td>
                  <td>{{ $presenca->alu_nome }}</td>
                  <td>
                     <!-- Switch -->
                     <div class="switch">
                        <label>
                           Ausente
                           <input type="checkbox" name="presenca[]" checked="checked" value="1">
                           <span class="lever"></span>
                           Presente
                        </label>
                     </div>
                  </td>
                  <td>
                     <div class="input-field">
                        <input type="hidden" name="aluno_id[]" value="{{ $presenca->alu_id }}">
                     </div>
                  </td>
               </tr>
            @endforeach
         </tbody>
      </table>
   </div>
</form>