diff --git a/packages/xod-arduino/src/formatTweakMessage.js b/packages/xod-arduino/src/formatTweakMessage.js
new file mode 100644
index 00000000..f1363736
--- /dev/null
+++ b/packages/xod-arduino/src/formatTweakMessage.js
@@ -0,0 +1,34 @@
+import * as R from 'ramda';
+
+import { unquote } from 'xod-func-tools';
+import * as XP from 'xod-project';
+
+import { def } from './types';
+
+import { byteLiteralToDecimal } from './templates';
+
+export default def(
+  'formatTweakMessage :: PatchPath -> NodeId -> DataValue -> String',
+  (nodeType, nodeId, value) => {
+    const prefix = `+XOD:${nodeId}`;
+
+    switch (XP.getTweakType(nodeType)) {
+      case XP.PIN_TYPE.NUMBER:
+        return `${prefix}:${value}\r\n`;
+      case XP.PIN_TYPE.BOOLEAN:
+        return `${prefix}:${value === 'True' ? '1' : '0'}\r\n`;
+      case XP.PIN_TYPE.BYTE:
+        return `${prefix}:${byteLiteralToDecimal(value)}\r\n`;
+      case XP.PIN_TYPE.PULSE:
+        return `${prefix}\r\n`;
+      case XP.PIN_TYPE.STRING:
+        return R.compose(
+          s => `${prefix}:${s}\r\n`,
+          R.slice(0, XP.getStringTweakLength(nodeType)),
+          unquote
+        )(value);
+      default:
+        return '';
+    }
+  }
+);
diff --git a/packages/xod-arduino/src/index.js b/packages/xod-arduino/src/index.js
index e6658989..4bffc708 100644
--- a/packages/xod-arduino/src/index.js
+++ b/packages/xod-arduino/src/index.js
@@ -8,3 +8,5 @@ export {
 export { default as messages } from './messages';
 
 export { LIVENESS } from './constants';
+
+export { default as formatTweakMessage } from './formatTweakMessage';
diff --git a/packages/xod-arduino/src/templates.js b/packages/xod-arduino/src/templates.js
index a3709e59..727441eb 100644
--- a/packages/xod-arduino/src/templates.js
+++ b/packages/xod-arduino/src/templates.js
@@ -100,6 +100,22 @@ const cppStringLiteral = def(
   )
 );
 
+export const byteLiteralToDecimal = R.ifElse(
+  R.test(/(b|h|d)$/),
+  R.converge(parseInt, [
+    R.init,
+    R.compose(
+      R.prop(R.__, {
+        b: 2,
+        h: 16,
+        d: 10,
+      }),
+      R.last
+    ),
+  ]),
+  plainDecimal => parseInt(plainDecimal, 10)
+);
+
 // Formats XOD byte literal into C++ byte literal
 // E.G.
 // 00011101b -> 0x1D
@@ -117,21 +133,7 @@ const cppByteLiteral = def(
       R.concat('0x'),
       R.toUpper,
       x => x.toString(16),
-      R.ifElse(
-        R.test(/(b|h|d)$/),
-        R.converge(parseInt, [
-          R.init,
-          R.compose(
-            R.prop(R.__, {
-              b: 2,
-              h: 16,
-              d: 10,
-            }),
-            R.last
-          ),
-        ]),
-        plainDecimal => parseInt(plainDecimal, 10)
-      )
+      byteLiteralToDecimal
     )
   )
 );
diff --git a/packages/xod-client-electron/src/debugger/sendTweakValuesMiddleware.js b/packages/xod-client-electron/src/debugger/sendTweakValuesMiddleware.js
new file mode 100644
index 00000000..9b537a6f
--- /dev/null
+++ b/packages/xod-client-electron/src/debugger/sendTweakValuesMiddleware.js
@@ -0,0 +1,39 @@
+import * as R from 'ramda';
+import * as XP from 'xod-project';
+import client from 'xod-client';
+import { formatTweakMessage } from 'xod-arduino';
+import { ipcRenderer } from 'electron';
+
+import { DEBUG_SERIAL_SEND } from '../shared/events';
+
+export default ({ getState }) => next => action => {
+  const state = getState();
+  const result = next(action);
+
+  if (
+    action.type === client.NODE_UPDATE_PROPERTY &&
+    client.isSerialDebugRunning(state)
+  ) {
+    const { id: nodeId, value, patchPath } = action.payload;
+    const nodeType = R.compose(
+      XP.getNodeType,
+      XP.getNodeByIdUnsafe(nodeId),
+      XP.getPatchByPathUnsafe(patchPath),
+      client.getProject
+    )(state);
+
+    if (XP.isTweakPath(nodeType)) {
+      const debuggerNodeId = R.compose(
+        R.prop(nodeId),
+        client.getInvertedDebuggerNodeIdsMap
+      )(state);
+
+      ipcRenderer.send(
+        DEBUG_SERIAL_SEND,
+        formatTweakMessage(nodeType, debuggerNodeId, value)
+      );
+    }
+  }
+
+  return result;
+};
diff --git a/packages/xod-client-electron/src/index.jsx b/packages/xod-client-electron/src/index.jsx
index 0cf4ae4a..b623ccfa 100644
--- a/packages/xod-client-electron/src/index.jsx
+++ b/packages/xod-client-electron/src/index.jsx
@@ -8,6 +8,7 @@ import popupsReducer from './popups/reducer';
 import uploadReducer from './upload/reducer';
 
 import stopDebuggerOnTabCloseMiddleware from './debugger/stopDebuggerOnTabCloseMiddleware';
+import sendTweakValuesMiddleware from './debugger/sendTweakValuesMiddleware';
 import autoupdateMiddleware from './view/autoupdateMiddleware';
 import installLibMiddleware from './view/installLibMiddleware';
 import arduinoDependenciesMiddleware from './arduinoDependencies/middleware';
@@ -18,6 +19,7 @@ const extraReducers = {
 };
 
 const extraMiddlewares = [
+  sendTweakValuesMiddleware,
   stopDebuggerOnTabCloseMiddleware,
   installLibMiddleware,
   autoupdateMiddleware,
diff --git a/packages/xod-client/src/debugger/selectors.js b/packages/xod-client/src/debugger/selectors.js
index 29e40116..c7656ee2 100644
--- a/packages/xod-client/src/debugger/selectors.js
+++ b/packages/xod-client/src/debugger/selectors.js
@@ -1,6 +1,6 @@
 import * as R from 'ramda';
 import { Maybe } from 'ramda-fantasy';
-import { foldMaybe, isAmong } from 'xod-func-tools';
+import { foldMaybe, isAmong, memoizeOnlyLast } from 'xod-func-tools';
 import { createSelector } from 'reselect';
 import {
   getCurrentTabId,
@@ -90,6 +90,11 @@ export const getDebuggerNodeIdsMap = R.compose(
   getDebuggerState
 );
 
+export const getInvertedDebuggerNodeIdsMap = R.compose(
+  memoizeOnlyLast(R.invertObj),
+  getDebuggerNodeIdsMap
+);
+
 export const getWatchNodeValues = R.compose(
   R.prop('watchNodeValues'),
   getDebuggerState
diff --git a/packages/xod-client/src/editor/containers/Patch/modes/debugging.jsx b/packages/xod-client/src/editor/containers/Patch/modes/debugging.jsx
index a9dd1172..acac7050 100644
--- a/packages/xod-client/src/editor/containers/Patch/modes/debugging.jsx
+++ b/packages/xod-client/src/editor/containers/Patch/modes/debugging.jsx
@@ -16,6 +16,9 @@ const debuggingMode = R.merge(selectingMode, {
   onNodeDoubleClick(api, nodeId, patchPath) {
     if (patchPath === XP.NOT_IMPLEMENTED_IN_XOD_PATH) {
       api.props.actions.openImplementationEditor();
+    } else if (XP.isConstantNodeType(patchPath) || XP.isTweakPath(patchPath)) {
+      // TODO: rename this action to something more suitable?
+      api.props.actions.selectConstantNodeValue(nodeId, api.props.patchPath);
     } else {
       api.props.actions.drillDown(patchPath, nodeId);
     }
diff --git a/packages/xod-client/src/editor/containers/Patch/modes/selecting.jsx b/packages/xod-client/src/editor/containers/Patch/modes/selecting.jsx
index 7589af50..b2cd484c 100644
--- a/packages/xod-client/src/editor/containers/Patch/modes/selecting.jsx
+++ b/packages/xod-client/src/editor/containers/Patch/modes/selecting.jsx
@@ -227,7 +227,8 @@ const selectingMode = {
   onNodeDoubleClick(api, nodeId, patchPath) {
     if (R.contains(patchPath, R.keys(XP.MANAGED_ATTACHMENT_FILENAMES))) {
       api.props.actions.openAttachmentEditor(patchPath);
-    } else if (XP.isConstantNodeType(patchPath)) {
+    } else if (XP.isConstantNodeType(patchPath) || XP.isTweakPath(patchPath)) {
+      // TODO: rename this action to something more suitable?
       api.props.actions.selectConstantNodeValue(nodeId, api.props.patchPath);
     } else {
       api.props.actions.switchPatch(patchPath);
diff --git a/packages/xod-client/src/index.js b/packages/xod-client/src/index.js
index 5bf991e2..26c75674 100644
--- a/packages/xod-client/src/index.js
+++ b/packages/xod-client/src/index.js
@@ -25,7 +25,7 @@ import { LOG_TAB_TYPE } from './debugger/constants';
 
 import { MESSAGE_BUTTON_CLICKED } from './messages/actionTypes';
 import { TAB_CLOSE, INSTALL_LIBRARIES_COMPLETE } from './editor/actionTypes';
-import { SAVE_ALL } from './project/actionTypes';
+import { SAVE_ALL, NODE_UPDATE_PROPERTY } from './project/actionTypes';
 
 import * as EditorConstants from './editor/constants';
 import * as UtilsConstants from './utils/constants';
@@ -82,7 +82,7 @@ export { LOG_TAB_TYPE } from './debugger/constants';
 
 export { MESSAGE_BUTTON_CLICKED } from './messages/actionTypes';
 export { TAB_CLOSE, INSTALL_LIBRARIES_COMPLETE } from './editor/actionTypes';
-export { SAVE_ALL } from './project/actionTypes';
+export { SAVE_ALL, NODE_UPDATE_PROPERTY } from './project/actionTypes';
 export { SERIAL_SESSION_STARTED } from './debugger/actionTypes';
 
 export * from './editor/selectors';
@@ -166,6 +166,7 @@ export default Object.assign(
     parseDebuggerMessage,
     TAB_CLOSE,
     SAVE_ALL,
+    NODE_UPDATE_PROPERTY,
     INSTALL_LIBRARIES_COMPLETE,
     MESSAGE_BUTTON_CLICKED,
     Messages: coreMessages,
diff --git a/packages/xod-project/src/patchPathUtils.js b/packages/xod-project/src/patchPathUtils.js
index 11833efc..36fe23c5 100644
--- a/packages/xod-project/src/patchPathUtils.js
+++ b/packages/xod-project/src/patchPathUtils.js
@@ -295,7 +295,15 @@ export const getSpecializationPatchPath = R.curry(
 // utils for tweak nodes
 //
 
-const tweakPathRegExp = new RegExp('^xod/debug/tweak-');
+const tweakPathRegExp = new RegExp(`^xod/debug/tweak-(${dataTypes.join('|')})`);
 
 // :: PatchPath -> Boolean
 export const isTweakPath = R.test(tweakPathRegExp);
+
+export const getTweakType = R.pipe(R.match(tweakPathRegExp), R.nth(1));
+
+export const getStringTweakLength = R.pipe(
+  R.match(/^xod\/debug\/tweak-string-(\d+)/),
+  R.nth(1),
+  n => parseInt(n, 10)
+);