diff --git a/.vscode/settings.json b/.vscode/settings.json
new file mode 100644
index 0000000..55712c1
--- /dev/null
+++ b/.vscode/settings.json
@@ -0,0 +1,3 @@
+{
+    "typescript.tsdk": "node_modules/typescript/lib"
+}
\ No newline at end of file
diff --git a/.vscode/tasks.json b/.vscode/tasks.json
index 3ccf9d1..246d755 100644
--- a/.vscode/tasks.json
+++ b/.vscode/tasks.json
@@ -1,27 +1,28 @@
 {
     // See https://go.microsoft.com/fwlink/?LinkId=733558
     // for the documentation about the tasks.json format
-    "version": "0.1.0",
-    "command": "npm",
-    "isShellCommand": true,
-    "showOutput": "always",
-    "suppressTaskName": true,
+    "version": "2.0.0",
     "tasks": [
         {
-            "taskName": "install",
-            "args": ["install"]
-        },
-        {
-            "taskName": "update",
-            "args": ["update"]
-        },
-        {
-            "taskName": "start",
-            "args": ["run", "start"]
-        },
-        {
-            "taskName": "test",
-            "args": ["run", "test"]
+            "type": "npm",
+            "script": "start",
+            "problemMatcher": {
+                "owner": "webpack",
+                "severity": "error",
+                "fileLocation": "relative",
+                "pattern": [
+                    {
+                        "regexp": "ERROR in (.*)",
+                        "file": 1
+                    },
+                    {
+                        "regexp": "\\((\\d+),(\\d+)\\):(.*)",
+                        "line": 1,
+                        "column": 2,
+                        "message": 3
+                    }
+                ]
+            }
         }
     ]
 }
\ No newline at end of file
diff --git a/app/script/components/DeviceView.tsx b/app/script/components/DeviceView.tsx
index 8c6470c..2671709 100644
--- a/app/script/components/DeviceView.tsx
+++ b/app/script/components/DeviceView.tsx
@@ -1,19 +1,19 @@
 import * as classNames from "classnames";
-import {observer} from "mobx-react";
+import { observer } from "mobx-react";
 import * as React from "react";
-import {Header, Item} from "semantic-ui-react";
-import {ProgramTable, RunSectionForm, SectionTable, SectionRunnerView} from ".";
+import { Header, Item } from "semantic-ui-react";
+import { ProgramTable, RunSectionForm, SectionRunnerView, SectionTable } from ".";
 
-import {SprinklersDevice} from "../sprinklers";
+import { SprinklersDevice } from "../sprinklers";
 import FontAwesome = require("react-fontawesome");
 
-const ConnectionState = ({connected}: { connected: boolean }) =>
+const ConnectionState = ({ connected }: { connected: boolean }) =>
     <span className={classNames({
         "device--connectionState": true,
         "device--connectionState-connected": connected,
         "device--connectionState-disconnected": !connected,
     })}>
-        <FontAwesome name={connected ? "plug" : "chain-broken"}/>
+        <FontAwesome name={connected ? "plug" : "chain-broken"} />
         &nbsp;
         {connected ? "Connected" : "Disconnected"}
     </span>;
@@ -21,22 +21,22 @@ const ConnectionState = ({connected}: { connected: boolean }) =>
 @observer
 export default class DeviceView extends React.PureComponent<{ device: SprinklersDevice }, {}> {
     render() {
-        const {id, connected, sections, programs, sectionRunner} = this.props.device;
+        const { id, connected, sections, programs, sectionRunner } = this.props.device;
         return (
             <Item>
-                <Item.Image src={require<string>("app/images/raspberry_pi.png")}/>
+                <Item.Image src={require<string>("app/images/raspberry_pi.png")} />
                 <Item.Content>
                     <Header as="h1">
                         <span>Device </span><kbd>{id}</kbd>
-                        <ConnectionState connected={connected}/>
+                        <ConnectionState connected={connected} />
                     </Header>
                     <Item.Meta>
 
                     </Item.Meta>
-                    <SectionRunnerView sectionRunner={sectionRunner}/>
-                    <SectionTable sections={sections}/>
-                    <RunSectionForm sections={sections}/>
-                    <ProgramTable programs={programs}/>
+                    <SectionRunnerView sectionRunner={sectionRunner} />
+                    <SectionTable sections={sections} />
+                    <RunSectionForm sections={sections} />
+                    <ProgramTable programs={programs} />
                 </Item.Content>
             </Item>
         );
diff --git a/app/script/components/DurationInput.tsx b/app/script/components/DurationInput.tsx
index 198d140..c1da564 100644
--- a/app/script/components/DurationInput.tsx
+++ b/app/script/components/DurationInput.tsx
@@ -1,11 +1,11 @@
 import * as React from "react";
-import {Input} from "semantic-ui-react";
-import {Duration} from "../sprinklers";
+import { Input, InputOnChangeData } from "semantic-ui-react";
+import { Duration } from "../sprinklers";
 
 export default class DurationInput extends React.Component<{
     duration: Duration,
-    onDurationChange?: (newDuration: Duration) => void;
-}, {}> {
+    onDurationChange: (newDuration: Duration) => void;
+}> {
     render() {
         const duration = this.props.duration;
         // const editing = this.props.onDurationChange != null;
@@ -13,25 +13,25 @@ export default class DurationInput extends React.Component<{
             <label>Duration</label>
             <div className="fields">
                 <Input type="number" className="field durationInput--minutes"
-                       value={duration.minutes} onChange={this.onMinutesChange}
-                       label="M" labelPosition="right"/>
+                    value={duration.minutes} onChange={this.onMinutesChange}
+                    label="M" labelPosition="right" />
                 <Input type="number" className="field durationInput--seconds"
-                       value={duration.seconds} onChange={this.onSecondsChange} max="60"
-                       label="S" labelPosition="right"/>
+                    value={duration.seconds} onChange={this.onSecondsChange} max="60"
+                    label="S" labelPosition="right" />
             </div>
         </div>;
     }
 
-    private onMinutesChange = (e, {value}) => {
-        if (value.length === 0 || isNaN(value)) {
+    private onMinutesChange = (e: React.SyntheticEvent<any>, { value }: InputOnChangeData) => {
+        if (value.length === 0 || isNaN(Number(value))) {
             return;
         }
         const newMinutes = parseInt(value, 10);
         this.props.onDurationChange(this.props.duration.withMinutes(newMinutes));
     }
 
-    private onSecondsChange = (e, {value}) => {
-        if (value.length === 0 || isNaN(value)) {
+    private onSecondsChange = (e: React.SyntheticEvent<any>, { value }: InputOnChangeData) => {
+        if (value.length === 0 || isNaN(Number(value))) {
             return;
         }
         const newSeconds = parseInt(value, 10);
diff --git a/app/script/components/ProgramTable.tsx b/app/script/components/ProgramTable.tsx
index 531d50c..2f867d9 100644
--- a/app/script/components/ProgramTable.tsx
+++ b/app/script/components/ProgramTable.tsx
@@ -14,7 +14,7 @@ export class ScheduleView extends React.PureComponent<{ schedule: Schedule }, {}
 
 @observer
 export default class ProgramTable extends React.PureComponent<{ programs: Program[] }, {}> {
-    private static renderRow(program: Program, i: number): JSX.Element[] {
+    private static renderRows(program: Program, i: number): JSX.Element[] | null {
         if (!program) {
             return null;
         }
@@ -57,7 +57,7 @@ export default class ProgramTable extends React.PureComponent<{ programs: Progra
                 </Table.Header>
                 <Table.Body>
                     {
-                        Array.prototype.concat.apply([], this.props.programs.map(ProgramTable.renderRow))
+                        Array.prototype.concat.apply([], this.props.programs.map(ProgramTable.renderRows))
                     }
                 </Table.Body>
             </Table>
diff --git a/app/script/components/RunSectionForm.tsx b/app/script/components/RunSectionForm.tsx
index 6ff15c9..b4a6d82 100644
--- a/app/script/components/RunSectionForm.tsx
+++ b/app/script/components/RunSectionForm.tsx
@@ -1,7 +1,6 @@
 import {computed} from "mobx";
 import {observer} from "mobx-react";
 import * as React from "react";
-import {SyntheticEvent} from "react";
 import {DropdownItemProps, DropdownProps, Form, Header, Segment} from "semantic-ui-react";
 import {DurationInput} from ".";
 import {Duration, Section} from "../sprinklers";
@@ -37,7 +36,7 @@ export default class RunSectionForm extends React.Component<{
         </Segment>;
     }
 
-    private onSectionChange = (e: SyntheticEvent<HTMLElement>, v: DropdownProps) => {
+    private onSectionChange = (e: React.SyntheticEvent<HTMLElement>, v: DropdownProps) => {
         this.setState({section: v.value as number});
     }
 
@@ -45,10 +44,13 @@ export default class RunSectionForm extends React.Component<{
         this.setState({duration: newDuration});
     }
 
-    private run = (e: SyntheticEvent<HTMLElement>) => {
+    private run = (e: React.SyntheticEvent<HTMLElement>) => {
         e.preventDefault();
+        if (typeof this.state.section !== "number") {
+            return;
+        }
         const section: Section = this.props.sections[this.state.section];
-        console.log(`should run section ${section} for ${this.state.duration}`);
+        console.log(`running section ${section} for ${this.state.duration}`);
         section.run(this.state.duration)
             .then((a) => console.log("ran section", a))
             .catch((err) => console.error("error running section", err));
diff --git a/app/script/index.tsx b/app/script/index.tsx
index 0202a3c..e8607c5 100644
--- a/app/script/index.tsx
+++ b/app/script/index.tsx
@@ -1,10 +1,10 @@
 import * as React from "react";
 import * as ReactDOM from "react-dom";
-import {AppContainer} from "react-hot-loader";
+import { AppContainer } from "react-hot-loader";
 
 import App from "./components/App";
-import {MqttApiClient} from "./mqtt";
-import {Message, UiStore} from "./ui";
+import { MqttApiClient } from "./mqtt";
+import { Message, UiStore } from "./ui";
 
 const client = new MqttApiClient();
 client.start();
@@ -15,14 +15,14 @@ uiStore.addMessage(new Message("asdf", "boo!", Message.Type.Error));
 const rootElem = document.getElementById("app");
 
 ReactDOM.render(<AppContainer>
-    <App device={device} uiStore={uiStore}/>
+    <App device={device} uiStore={uiStore} />
 </AppContainer>, rootElem);
 
 if (module.hot) {
     module.hot.accept("./components/App", () => {
         const NextApp = require<any>("./components/App").default as typeof App;
         ReactDOM.render(<AppContainer>
-            <NextApp device={device} uiStore={uiStore}/>
+            <NextApp device={device} uiStore={uiStore} />
         </AppContainer>, rootElem);
     });
 }
diff --git a/app/script/mqtt.ts b/app/script/mqtt.ts
index ecda84f..8dbc11a 100644
--- a/app/script/mqtt.ts
+++ b/app/script/mqtt.ts
@@ -1,26 +1,26 @@
-import {EventEmitter} from "events";
+import { EventEmitter } from "events";
 import "paho-mqtt";
 import {
     Duration,
-    ISectionRun,
     ISprinklersApi,
-    ITimeOfDay,
     Program,
+    ProgramItem,
     Schedule,
     Section,
+    SectionRun,
     SectionRunner,
     SprinklersDevice,
+    TimeOfDay,
 } from "./sprinklers";
-import {checkedIndexOf} from "./utils";
+import { checkedIndexOf } from "./utils";
 import MQTT = Paho.MQTT;
 
-export class MqttApiClient extends EventEmitter implements ISprinklersApi {
+export class MqttApiClient implements ISprinklersApi {
     client: MQTT.Client;
     connected: boolean;
     devices: { [prefix: string]: MqttSprinklersDevice } = {};
 
     constructor() {
-        super();
         this.client = new MQTT.Client(location.hostname, 1884, MqttApiClient.newClientId());
         this.client.onMessageArrived = (m) => this.onMessageArrived(m);
         this.client.onConnectionLost = (e) => this.onConnectionLost(e);
@@ -80,6 +80,10 @@ export class MqttApiClient extends EventEmitter implements ISprinklersApi {
 
     private processMessage(m: MQTT.Message) {
         // console.log("message arrived: ", m);
+        if (m.destinationName == null) {
+            console.warn(`revieved invalid message: ${m}`);
+            return;
+        }
         const topicIdx = m.destinationName.indexOf("/"); // find the first /
         const prefix = m.destinationName.substr(0, topicIdx); // assume prefix does not contain a /
         const topic = m.destinationName.substr(topicIdx + 1);
@@ -130,7 +134,7 @@ class MqttSprinklersDevice extends SprinklersDevice {
     doSubscribe() {
         const c = this.apiClient.client;
         this.subscriptions
-            .forEach((filter) => c.subscribe(filter, {qos: 1}));
+            .forEach((filter) => c.subscribe(filter, { qos: 1 }));
     }
 
     doUnsubscribe() {
@@ -186,7 +190,7 @@ class MqttSprinklersDevice extends SprinklersDevice {
         }
         matches = topic.match(/^section_runner$/);
         if (matches != null) {
-            (this.sectionRunner as MqttSectionRunner).onMessage(null, payload);
+            (this.sectionRunner as MqttSectionRunner).onMessage(payload);
             return;
         }
         matches = topic.match(/^responses\/(\d+)$/);
@@ -219,7 +223,15 @@ class MqttSprinklersDevice extends SprinklersDevice {
     }
 
     cancelSectionRunById(id: number) {
-        return this.makeRequest(`section_runner/cancel_id`, {id});
+        return this.makeRequest(`section_runner/cancel_id`, { id });
+    }
+
+    pauseSectionRunner() {
+        return this.makeRequest(`section_runner/pause`);
+    }
+
+    unpauseSectionRunner() {
+        return this.makeRequest(`section_runner/unpause`);
     }
 
     //noinspection JSMethodCanBeStatic
@@ -227,7 +239,7 @@ class MqttSprinklersDevice extends SprinklersDevice {
         return Math.floor(Math.random() * 1000000000);
     }
 
-    private makeRequest(topic: string, payload: object | string): Promise<IResponseData> {
+    private makeRequest(topic: string, payload: object | string = {}): Promise<IResponseData> {
         return new Promise<IResponseData>((resolve, reject) => {
             const payloadStr = (typeof payload === "string") ?
                 payload : JSON.stringify(payload);
@@ -254,7 +266,7 @@ interface IResponseData {
     [key: string]: any;
 }
 
-type ResponseCallback = (IResponseData) => void;
+type ResponseCallback = (data: IResponseData) => void;
 
 interface ISectionJSON {
     name: string;
@@ -276,8 +288,19 @@ class MqttSection extends Section {
     }
 }
 
+interface ITimeOfDayJSON {
+    hour: number;
+    minute: number;
+    second: number;
+    millisecond: number;
+}
+
+function timeOfDayFromJSON(json: ITimeOfDayJSON): TimeOfDay {
+    return new TimeOfDay(json.hour, json.minute, json.second, json.millisecond);
+}
+
 interface IScheduleJSON {
-    times: ITimeOfDay[];
+    times: ITimeOfDayJSON[];
     weekdays: number[];
     from?: string;
     to?: string;
@@ -285,7 +308,7 @@ interface IScheduleJSON {
 
 function scheduleFromJSON(json: IScheduleJSON): Schedule {
     const sched = new Schedule();
-    sched.times = json.times;
+    sched.times = json.times.map(timeOfDayFromJSON);
     sched.weekdays = json.weekdays;
     sched.from = json.from == null ? null : new Date(json.from);
     sched.to = json.to == null ? null : new Date(json.to);
@@ -322,11 +345,10 @@ class MqttProgram extends Program {
             this.enabled = json.enabled;
         }
         if (json.sequence != null) {
-            // tslint:disable:object-literal-sort-keys
-            this.sequence = json.sequence.map((item) => ({
-                section: item.section,
-                duration: Duration.fromSeconds(item.duration),
-            }));
+            this.sequence = json.sequence.map((item) => (new ProgramItem(
+                item.section,
+                Duration.fromSeconds(item.duration),
+            )));
         }
         if (json.sched != null) {
             this.schedule = scheduleFromJSON(json.sched);
@@ -334,23 +356,42 @@ class MqttProgram extends Program {
     }
 }
 
+export interface ISectionRunJSON {
+    id: number;
+    section: number;
+    duration: number;
+    startTime?: number;
+    pauseTime?: number;
+}
+
+function sectionRunFromJSON(json: ISectionRunJSON) {
+    const run = new SectionRun();
+    run.id = json.id;
+    run.section = json.section;
+    run.duration = Duration.fromSeconds(json.duration);
+    run.startTime = json.startTime == null ? null : new Date(json.startTime);
+    run.pauseTime = json.pauseTime == null ? null : new Date(json.pauseTime);
+    return run;
+}
+
 interface ISectionRunnerJSON {
-    queue: ISectionRun[];
-    current?: ISectionRun;
+    queue: ISectionRunJSON[];
+    current: ISectionRunJSON | null;
+    paused: boolean;
 }
 
 class MqttSectionRunner extends SectionRunner {
-    onMessage(topic: string, payload: string) {
+    onMessage(payload: string) {
         const json = JSON.parse(payload) as ISectionRunnerJSON;
         this.updateFromJSON(json);
     }
 
     updateFromJSON(json: ISectionRunnerJSON) {
-        if (!json.queue) { // null means empty queue
+        if (!json.queue || !json.queue.length) { // null means empty queue
             this.queue.clear();
         } else {
-            this.queue.replace(json.queue);
+            this.queue.replace(json.queue.map(sectionRunFromJSON));
         }
-        this.current = json.current;
+        this.current = json.current == null ? null : sectionRunFromJSON(json.current);
     }
 }
diff --git a/app/script/sprinklers.ts b/app/script/sprinklers.ts
index 403d733..d7900fc 100644
--- a/app/script/sprinklers.ts
+++ b/app/script/sprinklers.ts
@@ -1,4 +1,4 @@
-import {IObservableArray, observable} from "mobx";
+import { IObservableArray, observable } from "mobx";
 
 export abstract class Section {
     device: SprinklersDevice;
@@ -22,11 +22,22 @@ export abstract class Section {
     }
 }
 
-export interface ITimeOfDay {
+export class TimeOfDay {
     hour: number;
     minute: number;
     second: number;
     millisecond: number;
+
+    constructor(hour: number, minute: number = 0, second: number = 0, millisecond: number = 0) {
+        this.hour = hour;
+        this.minute = minute;
+        this.second = second;
+        this.millisecond = millisecond;
+    }
+
+    static fromDate(date: Date): TimeOfDay {
+        return new TimeOfDay(date.getHours(), date.getMinutes(), date.getSeconds(), date.getMilliseconds());
+    }
 }
 
 export enum Weekday {
@@ -34,17 +45,17 @@ export enum Weekday {
 }
 
 export class Schedule {
-    times: ITimeOfDay[] = [];
+    times: TimeOfDay[] = [];
     weekdays: Weekday[] = [];
-    from?: Date = null;
-    to?: Date = null;
+    from: Date | null = null;
+    to: Date | null = null;
 }
 
 export class Duration {
     minutes: number = 0;
     seconds: number = 0;
 
-    constructor(minutes: number, seconds: number) {
+    constructor(minutes: number = 0, seconds: number = 0) {
         this.minutes = minutes;
         this.seconds = seconds;
     }
@@ -82,11 +93,16 @@ export class Duration {
     }
 }
 
-export interface IProgramItem {
+export class ProgramItem {
     // the section number
     section: number;
     // duration of the run
     duration: Duration;
+
+    constructor(section: number, duration: Duration) {
+        this.section = section;
+        this.duration = duration;
+    }
 }
 
 export class Program {
@@ -101,7 +117,7 @@ export class Program {
     schedule: Schedule = new Schedule();
 
     @observable
-    sequence: IProgramItem[] = [];
+    sequence: ProgramItem[] = [];
 
     @observable
     running: boolean = false;
@@ -120,21 +136,38 @@ export class Program {
     }
 }
 
-export interface ISectionRun {
+export class SectionRun {
     id: number;
     section: number;
-    duration: number;
-    startTime?: Date;
+    duration: Duration;
+    startTime: Date | null;
+    pauseTime: Date | null;
+
+    constructor(id: number = 0, section: number = 0, duration: Duration = new Duration()) {
+        this.id = id;
+        this.section = section;
+        this.duration = duration;
+        this.startTime = null;
+        this.pauseTime = null;
+    }
+
+    toString() {
+        return `SectionRun{id=${this.id}, section=${this.section}, duration=${this.duration},` +
+            ` startTime=${this.startTime}, pauseTime=${this.pauseTime}}`;
+    }
 }
 
 export class SectionRunner {
     device: SprinklersDevice;
 
     @observable
-    queue: IObservableArray<ISectionRun> = observable([]);
+    queue: IObservableArray<SectionRun> = observable([]);
 
     @observable
-    current: ISectionRun = null;
+    current: SectionRun | null = null;
+
+    @observable
+    paused: boolean = false;
 
     constructor(device: SprinklersDevice) {
         this.device = device;
@@ -145,7 +178,7 @@ export class SectionRunner {
     }
 
     toString(): string {
-        return `SectionRunner{queue="${this.queue}", current="${this.current}"}`;
+        return `SectionRunner{queue="${this.queue}", current="${this.current}", paused=${this.paused}}`;
     }
 }
 
@@ -154,10 +187,10 @@ export abstract class SprinklersDevice {
     connected: boolean = false;
 
     @observable
-    sections: IObservableArray<Section> = [] as IObservableArray<Section>;
+    sections: IObservableArray<Section> = observable.array<Section>();
 
     @observable
-    programs: IObservableArray<Program> = [] as IObservableArray<Program>;
+    programs: IObservableArray<Program> = observable.array<Program>();
 
     @observable
     sectionRunner: SectionRunner;
@@ -169,12 +202,16 @@ export abstract class SprinklersDevice {
     abstract runProgram(program: number | Program): Promise<{}>;
 
     abstract cancelSectionRunById(id: number): Promise<{}>;
+
+    abstract pauseSectionRunner(): Promise<{}>;
+
+    abstract unpauseSectionRunner(): Promise<{}>;
 }
 
 export interface ISprinklersApi {
-    start();
+    start(): void;
 
     getDevice(id: string): SprinklersDevice;
 
-    removeDevice(id: string);
+    removeDevice(id: string): void;
 }
diff --git a/package.json b/package.json
index d698612..cd833bb 100644
--- a/package.json
+++ b/package.json
@@ -8,7 +8,7 @@
     "clean": "rm -rf ./dist ./build",
     "build": "webpack --config ./webpack/prod.config.js",
     "start": "webpack-dev-server --config ./webpack/dev.config.js",
-    "lint": "tslint \"app/script/**/*\" --force"
+    "lint": "tslint --project . --force"
   },
   "repository": {
     "type": "git",
@@ -29,6 +29,7 @@
     "@types/react": "^16",
     "@types/react-dom": "^15.5.0",
     "@types/react-fontawesome": "^1.5.0",
+    "@types/react-hot-loader": "^3.0.4",
     "@types/react-transition-group": "^1.1.1",
     "classnames": "^2.2.5",
     "core-js": "^2.4.1",
diff --git a/tsconfig.json b/tsconfig.json
index 88d4781..caae317 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -5,7 +5,8 @@
         "experimentalDecorators": true,
         "target": "es5",
         "lib": ["es6", "dom"],
-        "typeRoots": ["node_modules/@types"]
+        "typeRoots": ["node_modules/@types"],
+        "strict": true
     },
     "files": [
         "./node_modules/@types/webpack-env/index.d.ts",
diff --git a/tslint.json b/tslint.json
index c05a219..1c0575b 100644
--- a/tslint.json
+++ b/tslint.json
@@ -26,6 +26,13 @@
       {
         "order": "fields-first"
       }
+    ],
+    "object-literal-sort-keys": [
+      false
+    ],
+    "no-submodule-imports": false,
+    "no-unused-variable": [
+      true
     ]
   },
   "rulesDirectory": []
diff --git a/yarn.lock b/yarn.lock
index 34ff7c9..0333983 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -34,6 +34,12 @@
   dependencies:
     "@types/react" "*"
 
+"@types/react-hot-loader@^3.0.4":
+  version "3.0.4"
+  resolved "https://registry.yarnpkg.com/@types/react-hot-loader/-/react-hot-loader-3.0.4.tgz#7fc081509830c64218d8a99a865e2fb4a94572ad"
+  dependencies:
+    "@types/react" "*"
+
 "@types/react-transition-group@^1.1.1":
   version "1.1.2"
   resolved "https://registry.yarnpkg.com/@types/react-transition-group/-/react-transition-group-1.1.2.tgz#a349e70788a6dc723a5f439217011ef926c27b4f"