diff --git a/activity_log.txt b/activity_log.txt
new file mode 100755
index 0000000..adef32d
--- /dev/null
+++ b/activity_log.txt
@@ -0,0 +1,10 @@
+2022-07-11 20:20:30: Project Plan 
+Added:  (10000 * 5), Cost plan old: 0 | 50000_
+Data type (double * double), double | double
+Data type origin (double * NULL), string | double
+------
+2022-07-11 20:21:26: Project Plan 
+Deleted:  (10000 * 5), Cost plan old: 50000 | -0_
+Data type (double * double), double | double
+Data type origin (double * double), string | double
+------
diff --git a/app/Models/AssignMaterial.php b/app/Models/AssignMaterial.php
index f7abd89..7060c5c 100644
--- a/app/Models/AssignMaterial.php
+++ b/app/Models/AssignMaterial.php
@@ -5,6 +5,7 @@ namespace App\Models;
 use Illuminate\Database\Eloquent\Model;
 use App\Models\RequestMaterial;
 use App\Models\Activity;
+use Carbon\Carbon;
 
 class AssignMaterial extends Model
 {
@@ -29,14 +30,32 @@ class AssignMaterial extends Model
 		static::created(function($data) {
 			$activity = Activity::find($data->activity_id);
 			$material = RequestMaterial::where("id", $data->material_id)->first();
+			$old = $activity->rencana_biaya;
 			$activity->rencana_biaya += floatval($material->price) * floatval($data->qty_planning);
 			$activity->save();
+
+			$msg = Carbon::now()->toDateTimeString() . ": ".$activity->id." ".$activity->name.PHP_EOL;
+			$msg .= "Added: ".$material->desc." (".floatval($material->price)." * ".floatval($data->qty_planning)."), Cost plan old: ".$old." | +".$activity->rencana_biayaPHP_EOL;
+			$msg .= "Data type (".gettype(floatval($material->price))." * ".gettype(floatval($material->qty_planning))."), ".gettype(floatval($old))." | ".gettype(floatval($activity->rencana_biaya)).PHP_EOL;
+			$msg .= "Data type origin (".gettype($material->price)." * ".gettype($material->qty_planning)."), ".gettype($old)." | ".gettype($activity->rencana_biaya).PHP_EOL;
+			$msg .= "------".PHP_EOL;
+			file_put_contents('activity_log.txt', $msg, FILE_APPEND | LOCK_EX);
+
 		});
 
 		static::deleted(function($data) {
 			$activity = Activity::where('id', $data->activity_id)->first();
+			$old = $activity->rencana_biaya;
 			$activity->rencana_biaya -= floatval($data->budget) * floatval($data->qty_planning);
 			$activity->save();
+			$material = RequestMaterial::where("id", $data->material_id)->first();
+
+			$msg = Carbon::now()->toDateTimeString() . ": ".$activity->id." ".$activity->name.PHP_EOL;
+			$msg .= "Deleted: ".$material->desc." (".floatval($data->budget)." * ".floatval($data->qty_planning)."), Cost plan old: ".$old." | -".$activity->rencana_biaya.PHP_EOL;
+			$msg .= "Data type (".gettype(floatval($data->budget))." * ".gettype(floatval($data->qty_planning))."), ".gettype(floatval($old))." | ".gettype(floatval($activity->rencana_biaya)).PHP_EOL;
+			$msg .= "Data type origin (".gettype($data->budget)." * ".gettype($data->qty_planning)."), ".gettype($old)." | ".gettype($activity->rencana_biaya).PHP_EOL;
+			$msg .= "------".PHP_EOL;
+			file_put_contents('activity_log.txt', $msg, FILE_APPEND | LOCK_EX);
 		});
 
 	}