http://www.cytron.com.my/viewProduct.php?pcode=RFID-IDR-WIEGAND&name=Wiegand%20RFID%20Reader
the read range is 5cm and is not enough for my purpose...i need about 15cm... is there any method to modify its circuit and amplify its gain to achieve longer read range? i only need to read the front area of my robot...