diff --git a/scanner/app.js b/scanner/app.js
index b65e91a..515edd7 100644
--- a/scanner/app.js
+++ b/scanner/app.js
@@ -1,4 +1,8 @@
 // app.js
+import {
+  make_new_session_id,
+} from './utils.js';
+
 App({
   onLaunch() {
     // 展示本地存储能力
@@ -27,7 +31,8 @@ App({
   },
   globalData: {
     userInfo: null,
-    server_url: 'https://themblem.com'
+    server_url: 'https://themblem.com',
+    session_id: make_new_session_id(),
   },
 
   get_real_ip() {
diff --git a/scanner/pages/camera/camera.js b/scanner/pages/camera/camera.js
index 6757923..d202c31 100644
--- a/scanner/pages/camera/camera.js
+++ b/scanner/pages/camera/camera.js
@@ -15,6 +15,7 @@ import {
 import {
   get_camera_rule,
   get_system_info,
+  send_event,
 } from '../../utils.js'
 
 import { debug, info, error } from '../../log.js'
@@ -49,6 +50,7 @@ Page({
     qrarc_class: "sm",
     qrmarkers_class: "hidden",
     frame_upload_in_flight: 0,
+    frame_upload_failed: 0,
     frame_upload_time_cost: 0,
     frame_upload_interval_ms: 2000,
   },
@@ -89,8 +91,6 @@ Page({
     this.setData({
       ai_chat_mode: options.ai_chat_mode,
     });
-    var new_session_id = Date.now();
-    getApp().globalData.session_id = new_session_id;
     if (options.env == 'dev') {
       console.log("Using dev env settings.");
       getApp().globalData.server_url = 'https://dev.themblem.com';
@@ -392,36 +392,30 @@ Page({
       frame_upload_in_flight: this.data.frame_upload_in_flight + 1,
     });
     var seq_num = this.data.frame_upload_seq_num.toString().padStart(3, '0');
-    var fd = {
+    var event_data = {
       session_id: getApp().globalData.session_id,
       phone_model: getApp().globalData.phone_model,
       seq_num: seq_num,
       image_data_url: data_url,
     }
-    wx.request({
-      url: "https://research.themblem.com/event/camera-frame",
-      method: "POST",
-      data: JSON.stringify(fd),
-      header: {
-        "Content-Type": "application/json",
-      },
-      success: (res) => {
-        this.setData({
-          frame_uploaded: this.data.frame_uploaded + 1,
-          frame_upload_in_flight: this.data.frame_upload_in_flight - 1,
-          frame_upload_time_cost: Date.now() - begin,
-          frame_upload_interval_ms: this.data.frame_upload_interval_ms * 2,
-        });
-      },
-      fail: (e) => {
-        this.log("frame upload failed", e);
-        this.setData({
-          frame_upload_in_flight: this.data.frame_upload_in_flight - 1,
-          frame_upload_time_cost: Date.now() - begin,
-          frame_upload_interval_ms: this.data.frame_upload_interval_ms * 2,
-        });
-      },
-    });
+    var success_cb = (res) => {
+      this.setData({
+        frame_uploaded: this.data.frame_uploaded + 1,
+        frame_upload_in_flight: this.data.frame_upload_in_flight - 1,
+        frame_upload_time_cost: Date.now() - begin,
+        frame_upload_interval_ms: this.data.frame_upload_interval_ms * 2,
+      });
+    }
+    var fail_cb = (e) => {
+      this.log("frame upload failed", e);
+      this.setData({
+        frame_upload_failed: this.data.frame_upload_failed + 1,
+        frame_upload_in_flight: this.data.frame_upload_in_flight - 1,
+        frame_upload_time_cost: Date.now() - begin,
+        frame_upload_interval_ms: this.data.frame_upload_interval_ms * 2,
+      });
+    }
+    send_event("camera-frame", event_data, success_cb, fail_cb);
   },
   do_handle_frame(res) {
     if (this.busy) return;
@@ -441,7 +435,8 @@ Page({
       var uca1 = new Uint8ClampedArray(res.data);
       var uca = new Uint8ClampedArray(uca1);
       const data_url = data_url_from_frame(res.width, res.height, uca);
-      var r = frame_pre_check(res.width, res.height, uca, this.data.camera_sensitivity);
+      var r = frame_pre_check(res.width, res.height, uca,
+        this.data.camera_sensitivity)
       const result = r.result;
       this.log("frame_pre_check: ", JSON.stringify(result));
       this.setData({
diff --git a/scanner/utils.js b/scanner/utils.js
index 74bb1ee..ea92700 100644
--- a/scanner/utils.js
+++ b/scanner/utils.js
@@ -91,11 +91,30 @@ function goto_camera(redirect, opts) {
   });
 }
 
+function make_new_session_id() {
+  return `${Date.now()}-${Math.random().toString(36).substring(2, 15)}`;
+}
+
+function send_event(event_name, data, success_cb, fail_cb) {
+  wx.request({
+    url: 'https://research.themblem.com/event/' + event_name,
+    method: 'POST',
+    data: JSON.stringify(data),
+    header: {
+      'Content-Type': 'application/json',
+    },
+    success: success_cb,
+    fail: fail_cb,
+  });
+}
+
 module.exports = {
   get_system_info,
   get_phone_model,
   get_camera_rule,
   goto_camera,
-  formatTime
+  formatTime,
+  make_new_session_id,
+  send_event,
 }