diff --git a/lib/session/StreamingMsgPackEncoder.h b/lib/session/StreamingMsgPackEncoder.h
index 148b354..a9964e6 100644
--- a/lib/session/StreamingMsgPackEncoder.h
+++ b/lib/session/StreamingMsgPackEncoder.h
@@ -19,6 +19,21 @@ struct DummyWriter {
     void write(const void*, uint32_t) {}
 };
 
+class CopyWriter {
+public:
+    CopyWriter(uint8_t * bufferToWrite)
+        : bufferToWrite_( bufferToWrite )
+    {}
+
+    void write(const void* data, uint32_t length) {
+        memcpy(bufferToWrite_, data, length);
+        bufferToWrite_ += length;
+    }
+
+private:
+    uint8_t * bufferToWrite_;
+};
+
 template<typename Writer>
 class StreamingMsgPackEncoder
 {
@@ -141,7 +156,7 @@ class ChunkedStreamingMsgPackEncoder
 {
 public:
     ChunkedStreamingMsgPackEncoder(Writer * writer_, uint32_t offset, uint32_t maxSize)
-        : encoder_(writer_), offsetToStart_(offset), maxBytes_(maxSize), sentBytes_(0), sendingFinished_(false)
+            : encoder_(writer_), sentBytes_(0), maxBytes_(maxSize), offsetToStart_(offset), sendingFinished_(false)
     {}
 
     void sendMap16(byte size) {
@@ -175,7 +190,6 @@ public:
             return;
         }
 
-        uint32_t sizeForFullArray = sizeof(T) * length;
         uint32_t elementsToSkip = 0;
         if( sentBytes_ < offsetToStart_ ) {
             elementsToSkip = (offsetToStart_ - sentBytes_) / sizeof(T);
diff --git a/platformio.ini b/platformio.ini
index a1f3aba..a668b4b 100644
--- a/platformio.ini
+++ b/platformio.ini
@@ -20,7 +20,7 @@ lib_deps =
     AsyncTCP
     NTPClient
 
-[env:native]
-platform = native
-test_ignore = test_embedded
-build_flags = -g
\ No newline at end of file
+;[env:native]
+;platform = native
+;test_ignore = test_embedded
+;build_flags = -g
\ No newline at end of file
diff --git a/src/ConfigHardware.h b/src/ConfigHardware.h
index 8cfbef7..f9818fb 100644
--- a/src/ConfigHardware.h
+++ b/src/ConfigHardware.h
@@ -5,6 +5,7 @@ const int CONFIG_SCALE_DOUT_PIN = D2;
 const int CONFIG_SCALE_SCK_PIN = D3;
 const uint8_t CONFIG_TARE_AVG_COUNT = 50;       // number of measurements in tare-phase (to find 0 )
 const int CONFIG_VALUE_DIVIDER = 128;           // uint32 measurements are divided by this factor, before stored in uint16_t
+const int CONFIG_MEASURE_DELAY = 100;           // interval in ms between measurements
 
 
 const uint32_t CONFIG_SESSION_CHUNK_SIZE = 1024*8 - 3 * sizeof(uint32_t);
diff --git a/src/firmware_main.cpp b/src/firmware_main.cpp
index 46a50ba..f8d0532 100644
--- a/src/firmware_main.cpp
+++ b/src/firmware_main.cpp
@@ -26,14 +26,60 @@ template<typename Session_T>
 class SessionManager
 {
 public:
-    void begin();
+    SessionManager() : measuring_(false), lastCallTime_(0)
+    {}
+
+    void begin() {
+        scale.begin(CONFIG_SCALE_DOUT_PIN, CONFIG_SCALE_SCK_PIN);
+        scale.tare( CONFIG_TARE_AVG_COUNT );
+
+        session.init( timeClient.getEpochTime() );
+    }
+
+    void startMeasurements() {
+        measuring_ = true;
+    }
+
+    void stopMeasurements() {
+        measuring_ = false;
+    }
+
+    void iteration() {
+        if( ! measuring_ ) {
+            return;
+        }
+        uint16_t measurement;
+        scale.measure(measurement);
+        session.addPoint(measurement);
+
+        if( lastCallTime_ != 0) {
+            const long cycleDuration = millis() - lastCallTime_;
+            if( cycleDuration <= CONFIG_MEASURE_DELAY)
+            {
+                delay(CONFIG_MEASURE_DELAY - cycleDuration);
+            }
+            else
+            {
+                const long skipped = (cycleDuration / CONFIG_MEASURE_DELAY);
+                Serial.print("Warning: measurements skipped: ");
+                Serial.println(skipped);
+
+                for(int i=0; i < skipped; ++i)
+                  session.addPoint(measurement);
+
+                delay(CONFIG_MEASURE_DELAY * (skipped + 1) - cycleDuration);
+            }
+        }
+        lastCallTime_ = millis();
+    }
+
+    Session_T & getSession() { return session; }
 
-    void startMeasurements();
-    void stopMeasurements();
-    void iteration();
 private:
     MockScale scale;
     Session_T session;
+    bool measuring_;
+    long lastCallTime_;
 };
 
 SessionManager<Session_T> sessionManager;
@@ -48,43 +94,35 @@ void httpSetup(SessionManager<Session_T> * sessionManager)
     server.on("/api/session/start", HTTP_POST, [sessionManager](AsyncWebServerRequest * req) {
         req->send(200, "text/plain", F("OK"));
         sessionManager->startMeasurements();
+        Serial.println("Started measurements");
     });
     server.on("/api/session/stop", HTTP_POST, [sessionManager](AsyncWebServerRequest * req) {
         req->send(200, "text/plain", F("OK"));
         sessionManager->stopMeasurements();
+        Serial.println("Stopped measurements");
     });
     server.on("/api/session/data", HTTP_GET, [sessionManager](AsyncWebServerRequest * req) {
-        StreamingMsgPackEncoder<HttpWriterAdaptor> encoder(&adaptor);
-
-        req->send_P(200, "application/x-msgpack", const uint8_t * content, size_t len)
-
-    });
-
-
-    server.on("/", HTTP_GET, [](AsyncWebServerRequest *request){
-        request->send(200, "text/plain", "Hello, world");
-    });
-
-    // Send a GET request to <IP>/get?message=<message>
-    server.on("/get", HTTP_GET, [] (AsyncWebServerRequest *request) {
-        String message;
-        if (request->hasParam(PARAM_MESSAGE)) {
-            message = request->getParam(PARAM_MESSAGE)->value();
-        } else {
-            message = "No message sent";
+        uint32_t startIdx = 0;
+        if( req->hasParam("startIdx") ) {
+            startIdx = req->getParam("startIdx")->value().toInt();
         }
-        request->send(200, "text/plain", "Hello, GET: " + message);
-    });
 
-    // Send a POST request to <IP>/post with a form field message set to <message>
-    server.on("/post", HTTP_POST, [](AsyncWebServerRequest *request){
-        String message;
-        if (request->hasParam(PARAM_MESSAGE, true)) {
-            message = request->getParam(PARAM_MESSAGE, true)->value();
-        } else {
-            message = "No message sent";
-        }
-        request->send(200, "text/plain", "Hello, POST: " + message);
+        StreamingMsgPackEncoder<DummyWriter> encoderToDetermineSize(nullptr);
+        encoderToDetermineSize.setSizeCountMode(true);
+        sessionManager->getSession().serialize(encoderToDetermineSize, startIdx);
+        auto totalSize = encoderToDetermineSize.getContentLength();
+        Serial.print("Sending started of total size ");
+        Serial.println(totalSize);
+        req->send("application/x-msgpack", totalSize, [=](uint8_t *buffer, size_t maxLen, size_t index) -> size_t {
+            Serial.print("Partial send maxLen ");
+            Serial.print(maxLen);
+            Serial.print(" index ");
+            Serial.println("index");
+            CopyWriter copyWriter(buffer);
+            ChunkedStreamingMsgPackEncoder<CopyWriter> encoder(&copyWriter, index, index + maxLen);
+            sessionManager->getSession().serialize(encoder, startIdx);
+            return encoder.sentBytes() - index;
+        });
     });
 
     server.onNotFound(onNotFound);
@@ -112,15 +150,14 @@ void setup()
     // NTP
     timeClient.begin();
     timeClient.update();
-    session.init( timeClient.getEpochTime() );
 
-    // Scale
-    scale.begin(CONFIG_SCALE_DOUT_PIN, CONFIG_SCALE_SCK_PIN);
-    scale.tare( CONFIG_TARE_AVG_COUNT );
+    // Session
+    sessionManager.begin();
 
     // HTTP & Websocket server
-    httpSetup();
+    httpSetup(&sessionManager);
 }
 
 void loop() {
+    sessionManager.iteration();
 }