search php and mysql

I have a search engine with a normal form and everything, but in my bd I have some words with ñ and others without ñ in case the client enters it wrong.

The problem is that let's say I look for the word "estreñimiento" does not find anything even though this is the word in the database.

This is my query:

$sql = "SELECT * 
       FROM productos
       WHERE nombre LIKE '%$buscar%'
         OR descripcion LIKE '%$buscar%'
         OR observaciones LIKE '%$buscar%' 
         OR palabras_clave LIKE '%$buscar%'";
$result = $conn->query($sql);

Will anyone have a solution?