how to build a secret door

{"cid":"91148323","title":"LED Indicating Lights door metal detector Gate for Prison , 20 security level","imgUrl":"https:\/\/img.silkroadsl.com\/nimg\/b6\/4b\/67026f7eb148b762ba97d4ac7355-200x200-1.jpg","attrs":{"Price":"negotiation","Brand Name":"Zhonganxie","Model Number":"Arsenal-24a","Minimum Order Quantity":"1pc","Delivery Time":"5-7 working days","Certification":"CE, FCC, ROHS","Place of Origin":"China","Payment Terms":"T\/T","Supply Ability":"10000pcs per month","Packaging Details":"Carton boxes or according customer's need","Each zone sensitivity":"1-200 level","detection zones":"6\/12\/18","Working voltage":"100-240V\uff0c50\/60Hz","Security level":"1-20","Working environment temperature":"-20\u2103 ~ 85\u2103","Detection door packing size":"2290x630x180mm","Main box packing size":"755x340x210mm"}}