diff --git a/src/models/Hour.ts b/src/models/Hour.ts
new file mode 100644
index 0000000..38c3743
--- /dev/null
+++ b/src/models/Hour.ts
@@ -0,0 +1,10 @@
+import { TimeUnit } from './TimeUnit';
+
+export class Hour extends TimeUnit {
+  private static readonly DEFAULT_STEP = 1;
+  private static readonly MAX = 24;
+
+  constructor(value: number, step = Hour.DEFAULT_STEP) {
+    super(value, step, Hour.MAX);
+  }
+}
diff --git a/src/models/Minute.ts b/src/models/Minute.ts
new file mode 100644
index 0000000..4ff181a
--- /dev/null
+++ b/src/models/Minute.ts
@@ -0,0 +1,10 @@
+import { TimeUnit } from './TimeUnit';
+
+export class Minute extends TimeUnit {
+  private static readonly DEFAULT_STEP = 5;
+  private static readonly MAX = 50;
+
+  constructor(value: number, step = Minute.DEFAULT_STEP) {
+    super(value, step, Minute.MAX);
+  }
+}
diff --git a/src/models/TimeUnit.ts b/src/models/TimeUnit.ts
new file mode 100644
index 0000000..78b87b9
--- /dev/null
+++ b/src/models/TimeUnit.ts
@@ -0,0 +1,44 @@
+import { Direction } from '../types';
+
+export abstract class TimeUnit {
+  constructor(private _value: number, private _step: number, private _limit: number) {}
+
+  get value(): number {
+    return this._value;
+  }
+
+  setStringValue(stringValue: string): void {
+    if (this.isValidString(stringValue)) {
+      this.setValue(parseInt(stringValue));
+    }
+  }
+
+  stepUpdate(direction: Direction): void {
+    direction === Direction.UP ? this.increment() : this.decrement();
+  }
+
+  increment(): void {
+    this.setValue(this.value + this._step);
+  }
+
+  decrement(): void {
+    this.setValue(this.value - this._step);
+  }
+
+  toString(): string {
+    return this.value < 10 ? `0${this.value}` : this.value.toString();
+  }
+
+  private isValidString(valueStr: string): boolean {
+    const value = parseInt(valueStr);
+    return !isNaN(value) && value >= 0 && value <= this._limit;
+  }
+
+  private setValue(newValue: number): void {
+    if (newValue >= this._limit || newValue < 0) {
+      newValue = (newValue + this._limit) % this._limit;
+    }
+
+    this._value = newValue;
+  }
+}
diff --git a/src/models/index.ts b/src/models/index.ts
new file mode 100644
index 0000000..e973ccf
--- /dev/null
+++ b/src/models/index.ts
@@ -0,0 +1,3 @@
+export { TimeUnit } from './TimeUnit';
+export { Hour } from './Hour';
+export { Minute } from './Minute';
diff --git a/src/partials.ts b/src/partials.ts
new file mode 100644
index 0000000..42e49ca
--- /dev/null
+++ b/src/partials.ts
@@ -0,0 +1,9 @@
+import { html, TemplateResult } from 'lit-element';
+import { TimePickerCardConfig } from './types';
+
+export class Partial {
+  static error(error: string, origConfig: TimePickerCardConfig): TemplateResult {
+    const config = { error, origConfig };
+    return html`<hui-error-card ._config="${config}"></hui-error-card>`;
+  }
+}
diff --git a/src/styles.ts b/src/styles.ts
index 92d24b3..28eef57 100644
--- a/src/styles.ts
+++ b/src/styles.ts
@@ -1,8 +1,64 @@
 import { css } from 'lit-element';
 
 export const styles = css`
-  .card-warning {
-    background-color: var(--google-red-500, #ef5350);
-    color: #fff;
+  .time-picker-ha-card {
+    padding: 16px;
+    display: flex;
+    flex-direction: row;
+    align-items: center;
+    justify-content: center;
+  }
+
+  .time-form {
+    display: flex;
+    flex-direction: column;
+    align-items: center;
+    padding: 0 8px;
+  }
+
+  .time-picker-icon-up,
+  .time-picker-icon-down {
+    cursor: pointer;
+  }
+
+  .time-picker-icon-up {
+    padding: 8px;
+  }
+
+  .time-picker-icon-down {
+    margin-top: 8px;
+    padding: 8px;
+  }
+
+  .time-input {
+    width: 30px;
+    padding: 8px;
+    background: var(--card-background-color, transparent);
+    border: 0;
+    color: var(--text-color, #fff);
+    border-bottom: 1px solid var(--text-color, #fff);
+    text-align: center;
+    font-size: 1em;
+  }
+
+  input[type='number']::-webkit-inner-spin-button,
+  input[type='number']::-webkit-outer-spin-button {
+    -webkit-appearance: none;
+    margin: 0;
+  }
+
+  input[type='number'] {
+    -moz-appearance: textfield;
+  }
+
+  input[type='number']:focus {
+    outline: none;
+  }
+
+  input[type='number']:invalid {
+    box-shadow: none;
+    outline: none;
+    border: 0;
+    border-bottom: 2px solid red;
   }
 `;
diff --git a/src/time-picker-card.ts b/src/time-picker-card.ts
index 40a1db8..8a07b3e 100644
--- a/src/time-picker-card.ts
+++ b/src/time-picker-card.ts
@@ -1,8 +1,11 @@
 import { HomeAssistant } from 'custom-card-helpers';
+import { HassEntity } from 'home-assistant-js-websocket';
 import { CSSResult, customElement, html, LitElement, property, TemplateResult } from 'lit-element';
 import { CARD_VERSION } from './const';
+import { Hour, Minute, TimeUnit } from './models';
+import { Partial } from './partials';
 import { styles } from './styles';
-import { TimePickerCardConfig } from './types';
+import { Direction, TimePickerCardConfig } from './types';
 
 console.info(
   `%c  TIME-PICKER-CARD \n%c  Version ${CARD_VERSION}    `,
@@ -14,13 +17,69 @@ console.info(
 export class TimePickerCard extends LitElement {
   @property() private hass?: HomeAssistant;
   @property() private config?: TimePickerCardConfig;
+  @property() private hour?: Hour;
+  @property() private minute?: Minute;
+
+  private get entity(): HassEntity | undefined {
+    if (!this.config) {
+      return;
+    }
+
+    return this.hass?.states[this.config!.entity];
+  }
 
   render(): TemplateResult | null {
     if (!this.config || !this.hass) {
       return null;
     }
 
-    return html`<ha-card>TimePickerCard</ha-card>`;
+    if (!this.entity?.entity_id.startsWith('input_datetime')) {
+      return Partial.error('You must set an input_datetime entity', this.config);
+    }
+
+    if (!this.entity.attributes.has_time) {
+      return Partial.error(
+        'You must set an input_datetime entity that sets has_time: true',
+        this.config
+      );
+    }
+
+    this.hour = new Hour(this.entity?.attributes.hour ?? 0, this.config.hour_step);
+    this.minute = new Minute(this.entity?.attributes.minute ?? 0, this.config.minute_step);
+
+    return html`
+      <ha-card class="time-picker-ha-card">
+        <div class="time-form">
+          ${this.renderStepChanger(Direction.UP, this.hour)}
+          <input
+            class="time-input"
+            type="number"
+            placeholder="HH"
+            min="0"
+            max="24"
+            .value=${this.hour.toString()}
+            @change=${this.onHourChange}
+          />
+          ${this.renderStepChanger(Direction.DOWN, this.hour)}
+        </div>
+        <div class="time-separator">
+          :
+        </div>
+        <div class="time-form">
+          ${this.renderStepChanger(Direction.UP, this.minute)}
+          <input
+            class="time-input"
+            type="number"
+            placeholder="MM"
+            min="0"
+            max="60"
+            .value="${this.minute.toString()}"
+            @change=${this.onMinuteChange}
+          />
+          ${this.renderStepChanger(Direction.DOWN, this.minute)}
+        </div>
+      </ha-card>
+    `;
   }
 
   setConfig(config): void {
@@ -29,7 +88,7 @@ export class TimePickerCard extends LitElement {
     }
 
     if (!config.entity) {
-      throw new Error('You need to set an entity');
+      throw new Error('You must set an entity');
     }
 
     this.config = config;
@@ -39,6 +98,45 @@ export class TimePickerCard extends LitElement {
     return 3;
   }
 
+  onHourChange({ target: { value } }: { target: HTMLInputElement }): void {
+    this.hour!.setStringValue(value);
+    this.callService();
+  }
+
+  onMinuteChange({ target: { value } }: { target: HTMLInputElement }): void {
+    this.minute!.setStringValue(value);
+    this.callService();
+  }
+
+  private renderStepChanger(direction: Direction, unit: TimeUnit): TemplateResult {
+    const onIconClick = (): void => {
+      unit.stepUpdate(direction);
+      this.callService();
+    };
+
+    const className = `time-picker-icon-${direction}`;
+
+    return html`
+      <div class=${className} @click=${onIconClick}>
+        <ha-icon .icon="mdi:arrow-${direction}"></ha-icon>
+        <mwc-ripple id="ripple"></mwc-ripple>
+      </div>
+    `;
+  }
+
+  private callService(): Promise<void> {
+    if (!this.hass) {
+      throw new Error('Unable to update datetime');
+    }
+
+    const time = `${this.hour!.value}:${this.minute!.value}:00`;
+
+    return this.hass.callService('input_datetime', 'set_datetime', {
+      entity_id: this.entity?.entity_id,
+      time,
+    });
+  }
+
   static get styles(): CSSResult {
     return styles;
   }
diff --git a/src/types.ts b/src/types.ts
index 95415be..ce98d78 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -1,3 +1,10 @@
 export interface TimePickerCardConfig {
   entity: string;
+  hour_step?: number;
+  minute_step?: number;
+}
+
+export enum Direction {
+  UP = 'up',
+  DOWN = 'down',
 }