[
  {"node_id":"N01","temperature":28.4,"humidity":71,"ph":6.4,"ec":1.8,"status":"normal"},
  {"node_id":"N02","temperature":31.2,"humidity":63,"ph":5.8,"ec":2.1,"status":"warning"},
  {"node_id":"N03","temperature":27.9,"humidity":76,"ph":6.7,"ec":1.6,"status":"normal"},
  {"node_id":"N04","temperature":34.1,"humidity":55,"ph":5.4,"ec":2.5,"status":"critical"},
  {"node_id":"N05","temperature":29.3,"humidity":69,"ph":6.2,"ec":1.9,"status":"normal"}
]