diff --git a/src/controllers/storeController.js b/src/controllers/storeController.js
index e93b00fe..af81da60 100644
--- a/src/controllers/storeController.js
+++ b/src/controllers/storeController.js
@@ -497,6 +497,15 @@ exports.addStore = async (request, reply) => {
     return result.seq;
   };
 
+  const generatewaterlevelslavesensorId = async () => {
+    const result = await Counter.findOneAndUpdate(
+      { _id: 'waterlevelslavesensor_id' },
+      { $inc: { seq: 1 } },
+      { upsert: true, new: true }
+    );
+    return result.seq;
+  };
+
   const moment = require('moment');
   exports.createwaterlevelSensor = async (req, reply) => {
     try {
@@ -560,4 +569,49 @@ exports.addStore = async (request, reply) => {
       throw boom.boomify(err);
     }
   };
-  
\ No newline at end of file
+  
+
+  exports.addSlave = async (req, reply) => {
+    try {
+      const hardwareId = req.params.hardwareId;
+      const { tankhardwareId, type, indate, hardwareId_company } = req.body;
+
+      // Find the main hardware by hardwareId
+      const mainHardware = await WaterLeverSensor.findOne({ hardwareId });
+
+      if (!mainHardware) {
+        reply.code(404).send({ message: "Main hardware not found" });
+        return;
+      }
+
+      // Check if the slave's hardwareId already exists
+      const existingSlave = mainHardware.slaves.tankhardware.find(slave => slave.tankhardwareId === tankhardwareId);
+
+      if (existingSlave) {
+        reply.code(400).send({ message: "Slave hardware ID already exists for this main hardware" });
+        return;
+      }
+      var slave_seq_id = await generatewaterlevelslavesensorId();
+      const date = moment().format('MM-DD');
+      const prefix = 'AS-' + date + '--SLAOV1-';
+      var slaveId = `${prefix}${slave_seq_id}`;
+      // Create new slave
+      const newSlave = {
+        tankhardwareId,
+        slaveId: slaveId, 
+        type,
+        indate,
+        hardwareId_company
+      };
+
+      // Add the new slave to the main hardware's slaves array
+      mainHardware.slaves.tankhardware.push(newSlave);
+
+      // Save the updated main hardware
+      const updatedHardware = await mainHardware.save();
+
+      reply.code(200).send(updatedHardware);
+    } catch (err) {
+      reply.code(500).send(err);
+    }
+};
diff --git a/src/routes/storeRoute.js b/src/routes/storeRoute.js
index 584d8faf..ed56109c 100644
--- a/src/routes/storeRoute.js
+++ b/src/routes/storeRoute.js
@@ -213,5 +213,35 @@ fastify.get("/api/getHardware/:storeId", {
 });
 
 
+
+fastify.post("/api/addSlave/:hardwareId", {
+  schema: {
+    description: "This is for adding a slave to the water level sensor",
+    tags: ["Store-Data"],
+    summary: "Add a slave to the water level sensor",
+    params: {
+      required: ["hardwareId"],
+      type: "object",
+      properties: {
+        hardwareId: {
+          type: "string",
+          description: "Main hardware ID",
+        },
+      },
+    },
+    body: {
+      type: "object",
+      properties: {
+        tankhardwareId: { type: "string" },
+        type: { type: "string" },
+        indate: { type: "string" },
+        hardwareId_company: { type: "string" }
+      },
+    },
+  },
+  handler: storeController.addSlave,
+});
+
+
 next();
 };