diff --git a/index.html b/index.html
index d343f95..05f3ada 100644
--- a/index.html
+++ b/index.html
@@ -36,7 +36,7 @@
         <ul>
             <li><br/><a class="" href="https://jakedowns.github.io/webxr.html">WebXR + WebGPU Demos!</a></li>
             <li><br/><a class="" href="https://github.com/jakedowns/xreal-webxr">View Source For This Repo on Github</a></li>
-            <li><br/><a class="" href="https://gist.github.com/CGamesPlay/b3ea7740ea8715d19e89f5511491519f">HELP! We need your help finishing these FREE, OPEN-SOURCE COMMUNITY-CONTRIBUTED, DRIVERS! Please help us fix the YAW drift!</a></li>
+            <!-- <li><br/><a class="" href="https://gist.github.com/CGamesPlay/b3ea7740ea8715d19e89f5511491519f">HELP! We need your help finishing these FREE, OPEN-SOURCE COMMUNITY-CONTRIBUTED, DRIVERS! Please help us fix the YAW drift!</a></li> -->
         </ul>
     </div>
 
diff --git a/index_old.html b/index_old.html
index f5e146f..46b2b5d 100644
--- a/index_old.html
+++ b/index_old.html
@@ -74,6 +74,7 @@
 	<div id="connect"><button>connect</button></div>
     <div id="disconnect" onclick="disconnectDevices()"><button>disconnect</button></div>
     <div id="startIMU" style="display: none;" onclick="startIMU()"><button>start headtracking</button></div>
+    <div id="stopIMU" style="display: none;" onclick="stopIMU()"><button>stop headtracking</button></div>
     <div id="hadConnect"></div>
     <div id="sn"></div>
     <div id="firmwareMcu"></div>
@@ -430,7 +431,19 @@
     }
 
     window.startIMU = function(){
-        Manager.startIMU();
+        Manager.startIMU().then(result=>{
+            console.warn('Manager.startIMU().then...',{result})
+        }).catch(err=>{
+            console.error(err)
+        });
+    }
+
+    window.stopIMU = function(){
+        Manager.stopIMU().then(result=>{
+            console.warn('Manager.stopIMU().then...',{result})
+        }).catch(err=>{
+            console.error(err)
+        });
     }
 
     window.disconnectDevices = () => {
diff --git a/js_air/glasses.js b/js_air/glasses.js
index bb5eb3b..19f6763 100644
--- a/js_air/glasses.js
+++ b/js_air/glasses.js
@@ -392,18 +392,16 @@ export default class Glasses extends EventTarget {
     sendReport(msgId, payload) {
         const data = new Uint8Array(payload);
         const cmd = Protocol.cmd_build(msgId, data);
-        // console.log({
-        //     msgId,
-        //     payload,
-        //     data,
-        //     cmd
-        // })
+        
+        console.warn('js_air:sendReport',{msgId,payload})
 
         console.table([{
+            id: 'sendReport',
             dir: 'OUT',
             msgId: [msgId, '0x'+(msgId.toString(16))].join(' '),
             key: Protocol.keyForHex(msgId),
             payload: data.join(' '),
+            _input_payload: payload,
             cmd: cmd.map(b => b.toString(16).padStart(2, "0")).join(' ')
         }])
         this._device.sendReport(0x00, cmd);
diff --git a/js_air/manager.js b/js_air/manager.js
index d14199e..773f9f8 100644
--- a/js_air/manager.js
+++ b/js_air/manager.js
@@ -511,9 +511,9 @@ export async function getSN() {
 /** init air IMU tracking mode */
 export async function startIMU() {
     if(!glasses){
-        return 'no device connected'
+        return Promise.reject('no device connected')
     }
-    return glasses.sendReportTimeout(Protocol.MESSAGES.R_INIT_IMU_TRACKING_SESSION)
+    return glasses.sendReportTimeout(Protocol.MESSAGES.W_TOGGLE_IMU, [1])
         .then(report => {
             console.warn('startIMU -> report',report);
             if (reportSuccess(report)){
@@ -524,6 +524,22 @@ export async function startIMU() {
         })
 }
 
+export async function stopIMU() {
+    if(!glasses){
+        return 'no device connected'
+    }
+    // arg 2: 0 is what turns "off" the stream
+    return glasses.sendReportTimeout(Protocol.MESSAGES.W_TOGGLE_IMU, [0])
+        .then(report => {
+            console.warn('stopIMU -> report',report);
+            if (reportSuccess(report)){
+                return String.fromCharCode.apply(null, report.payload);
+            }else{
+                console.error('error w/ report',report)
+            }
+        })
+}
+
 /** read air glassess Brightness */
 export async function getBrightness() {
     let glasses = await common.connectDevice();
diff --git a/js_air/protocol.js b/js_air/protocol.js
index 87b086e..d144302 100644
--- a/js_air/protocol.js
+++ b/js_air/protocol.js
@@ -10,10 +10,10 @@ const RESERVED_OFS = 17;
 
 export const NREAL_VENDOR_ID = 0x3318;
 export const BOOT_PRODUCT_ID = 0x0423;
-
+export const IMU_TIMEOUT = 250;
 
 export const MESSAGES = {
-    W_CANCEL_ACTIVATION: 0x19,
+    
     R_MCU_APP_FW_VERSION: 0x26,//MCU APP FW version.
     R_GLASSID: 0x15,//MCU APP FW version.
     // R_DSP_APP_FW_VERSION: 0x21,//DSP APP FW version.
@@ -22,6 +22,9 @@ export const MESSAGES = {
     W_ACTIVATION_TIME: 0x2A,//Write activation time
     W_SLEEP_TIME: 0x1E,//Write unsleep time
 
+    W_TOGGLE_IMU: 0x19, 
+    W_CANCEL_ACTIVATION: 0x19,
+
     // R_IS_NEED_UPGRADE_DSP_FW: 0x49,//Check whether the DSP needs to be upgraded.
     // W_FORCE_UPGRADE_DSP_FW: 0x69,//Force upgrade DSP.
     R_DSP_VERSION: 0x18,//DSP APP FW version.
diff --git a/js_light/glasses.js b/js_light/glasses.js
index c640d00..f713e2d 100644
--- a/js_light/glasses.js
+++ b/js_light/glasses.js
@@ -32,6 +32,7 @@ export default class Glasses extends EventTarget {
 
     // light connect
     sendReport(msgId, payload, option) {
+        console.warn('js_light:sendReport',{msgId,payload,option})
         const data = new Uint8Array(payload);
         const cmd = Protocol.cmd_build(msgId, data, option);
         this._device.sendReport(0x00, cmd);