Playing Undertale on Android using a gaming keyboard (game keyboard) opens up new opportunities for precise control and comfortable gameplay. However, the standard operating system settings are often not optimized to fully work with USB or Bluetooth keyboards in games. This article will help you figure out how to properly connect your device, set up key mapping (key mapping), avoid input lags, and adapt controls to specific Undertale s—from battle style bullet hell to dialogue threads.

Features Undertale on mobile platforms is that the game was originally developed for PC with keyboard controls. The Android port retains the original mechanics, but requires additional effort to work correctly with external input devices. We will consider both hardware solutions (via an OTG cable or Bluetooth) and software solutions - using key emulators (Octopus, Key Mapper) and specialized launchers like Xbox Game Pass or Steam Link for streaming from a PC.

It is important to consider that performance will depend on the smartphone model, Android version and keyboard type. For example, mechanical keyboards with NKRO (N-Key Rollover) may conflict with the HID protocol on some devices, and Bluetooth keyboards may introduce delays of up to 30-50 ms. In this article you will find ways to minimize these problems and achieve a response that is as close as possible to a PC.

1. Compatibility: which keyboard is suitable for Undertale on Android

Not all gaming keyboards work equally well with Android. Main selection criteria:

  • 🔌 Connection type: USB (via OTG) or Bluetooth. Wired keyboards usually have lower latency but require an adapter. Wireless ones are more convenient, but can slow down in dynamic scenes (for example, in a battle with Sans).
  • 🎮 HID protocol support: The device must be recognized by Android as a standard keyboard, and not as an "unknown USB device". Check this in Settings → Connected devices.
  • ⚡ Power consumption: Some mechanical keyboards (for example Razer BlackWidow or SteelSeries Apex) require additional power via the USB hub, otherwise Android may turn them off due to lack of current.
  • 📱 Compatibility with your smartphone: Older devices running Android 9 and below may not support USB Host Mode or have restrictions on the number of simultaneously connected HID devices.

For testing we used the following models:

Keyboard modelConnection typeLatency (ms)OTG required?Notes
Keychron K2Bluetooth/USB-C15-20Yes (for USB)Works great with Samsung Galaxy S22, but requires flashing for NKRO.
Razer TurretBluetooth25-30NoBuilt-in phone stand, but high latency in battles.
Redragon K552USB (mini)10-12YesBudget option, but requires a USB hub with external power.
Logitech G Pro XBluetooth/USB18-22Yes (for USB)Supports Lightspeed (low latency), but expensive.
⚠️ Attention: If your smartphone does not support USB OTG, the keyboard will not work even with an adapter. Check compatibility through the app USB OTG Checker or in the device specifications.

For Undertale the response of the keys Z, X, C (actions/menu) and arrows is critical. If the keyboard does not recognize simultaneously pressed keys (for example, ← + Z), you will need to configure anti-ghosting or use software mapping.

2. Connecting a keyboard to Android: step-by-step guide

The connection process depends on the type of keyboard. Let's consider both options:

2.1. Wired connection via OTG

You will need:

  • 🔌 OTG adapter (Micro-USB or USB-C depending on the smartphone connector).
  • ⚡ USB hub with power (optional if the keyboard requires a lot of power).
  • 📱 Supported smartphone USB Host Mode (most devices on Android 6.0+).

Check OTG support in the smartphone settings

Connect the OTG adapter to the phone

Connect the keyboard with the adapter (if necessary via USB-hub)

Run Undertale and check key recognition -->

If the keyboard is not detected:

  1. Reboot your smartphone with the keyboard connected.
  2. Try another OTG adapter (cheap Chinese models often unstable).
  3. Enable developer mode and activate the option USB debugging (sometimes helps with HID conflicts).

2.2. Wireless connection via Bluetooth

Algorithm:

  1. Turn on Bluetooth on the keyboard (usually hold down the button Fn + B or a separate switch).
  2. On your smartphone, go to Settings → Connected devices → Bluetooth.
  3. Click Add a new device and select a keyboard from the list.
  4. If prompted, enter the PIN code (usually 0000 or 1234).
⚠️ Attention: Some keyboards (for example, Razer) require proprietary software for full functionality. On Android, such software is not available, so some functions (backlight, macros) will not work.

After connecting, check the response of the keys in any text editor (for example, Google DocsIf). characters repeat or disappear - this is a sign problems with the driver or lack of power (for USB keyboards).

Wired via OTG

Bluetooth keyboard

I don’t know, not yet selected

I already have a gaming keyboard for PC-->

3. Setting up controls in Undertale: key mapping

Undertale on Android does not support keyboard controls by default - the game is designed for touch input. To remap the keys, you will need one of the following solutions:

3.1. Using a key emulator (Key Mapper)

Applications like Octopus or Key Mapper allow you to emulate screen touches by pressing keys. Download them from Google Play or APKMirror (some applications have been removed from the official store).

Instructions for Octopus:

  1. Run Octopus and grant overlay rights (Settings → Accessibility → Octopus).
  2. Select Undertale from the list of installed games.
  3. Click Add key and map the keys to the virtual buttons on the screen:
    • 🔺 Z → Button "Attack/Select"
    • 🔻 X → "Action/Cancel" button
    • 🔘 Arrows → Character movement
    • 🔼 C → "Items" button
  • Save the profile and launch the game through Octopus.

    • Advantages this method: flexibility of settings, support for key combinations (for example, Z + → for running). Disadvantages: possible delays (5-15 ms) and the need to keep the application active in the background.

    3.2. Streaming from a PC via Steam Link or Xbox Game Pass

    If your PC is powerful enough, you can run Undertale through it and stream the image to Android using the keyboard as the main input device. To do this:

    1. Install Steam Link or Xbox Game Pass on your smartphone.
    2. Connect the keyboard to the PC (via USB or Bluetooth).
    3. Start broadcasting the game via a local network.

      4. This method guarantees minimal latency (if the router supports 5 GHz Wi-Fi) and full compatibility with the keyboard, but requires a powerful PC and a stable Internet connection.

      💡

      B Octopus you can create several profiles for different scenes Undertale. For example, one for battles (with priority on keys Z/X/C), the other for dialogues (with emphasis on arrows).

      4. Optimizing performance: how to reduce lag

      Input lag (input lag) is the main problem when using the keyboard on Android. In dynamic scenes (for example, in battle with Mettaton EX), even 30 ms can become critical. Here's how to reduce lag:

      • 📶 Use 5 GHz Wi-Fi for Bluetooth keyboards or streaming. At the 2.4 GHz frequency, interference from other devices increases the latency.
      • 🔋 Activate performance mode on your smartphone: Settings → Battery → Performance mode (name may vary).
      • 🗑️ Close background applications, especially instant messengers and social networks. They take up RAM and CPU time.
      • 🎮 Turn off vibration in settings Undertale and keyboards (if any). Vibration response adds latency.

      For accurate latency diagnosis, use the app Input Lag Test (available in Google Play). Normal values for a comfortable game:

      • USB keyboard: 10-20 ms (optimal for Undertale).
      • Bluetooth keyboard: 20-35 ms (acceptable, but noticeable in battles).
      • Wi-Fi streaming: 40-60 ms (suitable only for dialogues).

    If the delay exceeds 50 ms, try:

    1. Connect the keyboard directly to your smartphone (if you used Bluetooth).
    2. Switch to a wired Internet connection (for streaming).
    3. Lower graphic settings in Undertale (in the game menu).
    How to check the latency without applications?

    Open any text editor on your smartphone and quickly press a key (for example, A) 10 times. If there is a delay between characters of more than 0.1 second, this is a sign of high lag. Compare with input on a PC for objectivity.

    5. Solving typical problems

    Even after correct settings, errors may occur:

    ProblemCauseSolution
    The keyboard connects, but the keys do not work in the gameUndertale does not support direct keyboard inputUse Octopus or streaming from a PC
    Keys are pressed from delay or repeatDriver conflict or lack of powerConnect via a powered USB hub or restart the device
    The keyboard turns off after 5-10 minutesEnergy saving AndroidDisable battery optimization for the keyboard in the settings
    Key combinations do not work (for example, Z + →)NKRO or driver limitationConfigure macros in Octopus or update keyboard firmware

    If the keyboard is detected as an "unknown device":

    1. Check whether your smartphone supports USB HID class for keyboards. Some budget models (for example, Redmi 7A) have limitations.
    2. Update the keyboard firmware via a PC (if available). For example, for Keychron this is done via Via Software.
    3. Try connecting the keyboard to another device (tablet or PC) - if the problem persists, the device itself is faulty.
    ⚠️ Attention: On some smartphones (for example Samsung Galaxy A-series), charging may be blocked when connecting a keyboard via OTG. Use a USB hub with a power port to avoid draining the battery while playing.

    6. Additional settings for comfortable gameplay.

    In addition to the basic key settings, you can optimize other aspects:

    • 🎵 Disable system sounds: Settings → Sound Deactivate "Keypress sounds" and "Vibration when typing". This will reduce the load on the processor.
    • 🔄 Set up auto-repeat keys: In some keyboards (for example, Logitech), you can reduce the auto-repeat delay in proprietary software. This is useful for long presses (for example, hold → in dialogues).
    • 🖥️ Use the game mode: On smartphones ASUS ROG, Black Shark or RedMagic activate game mode for prioritization resources.
    • 🔧 Reassign rarely used keys: For example, assign Tab to opening the inventory, and Shift to running.

    For fans of speedruns (timed passage) it is useful to create a separate profile in Octopus with:

    • Macros for quickly selecting items (C + 1/2/3).
    • Disabled prompts (so as not to waste time reading).
    • Simplified controls for battles (for example, WASD instead of arrows).
    💡

    For minimal latency, use a wired connection, disable background processes and activate performance mode Even 10 ms can be decisive in battles with Sans or Muffet.

    7. Alternative control methods

    If setting up the keyboard seems too complicated, consider the alternatives:

    • 🎮 Gamepad: Connect Xbox Controller or DualShock 4 via Bluetooth. Undertale has built-in support for gamepads, but the controls are less precise than on a keyboard.
    • 🖱️ Mouse + keyboard: Some launchers (for example Xbox Game Pass) allow you to use the mouse for aiming in battles, and the keyboard for actions.
    • 📱 Touch overlays: Applications like Mantis Gamepad create virtual buttons on top of the game that can be pressed with your fingers or a stylus.

    For gamepads, the setup is simpler:

    1. Connect the controller to your smartphone via Bluetooth.
    2. Run Undertale —the game should automatically recognize the gamepad.
    3. If necessary, reassign the buttons in the game settings menu.

    The main disadvantage of gamepads is the difficulty of precise control in battles (for example, when dodging attacks Mettaton). The keyboard gives an advantage here.

    FAQ: Frequently asked questions about setup

    Can I use a laptop keyboard?

    Yes, but only if it has a separate USB output or supports Bluetooth. Keyboards built into a laptop cannot be connected to a smartphone. Please note that membrane keyboards (unlike mechanical ones) can have a high latency.

    Why do the keys respond with a delay in battles, but not in the menu?

    This is due to the fact that Undertale Android is optimized for touch control. In the menu, the CPU load is minimal, and in battles the game processes physics, animation and input simultaneously. Try lowering the graphic settings or closing background applications.

    Can I play on a tablet with a keyboard?

    Yes, the setup process is similar. Tablets (for example Samsung Tab S8 or iPad with an Android emulator) are even preferable due to their larger screen. The main thing is to make sure that the tablet supports USB OTG or Bluetooth keyboards.

    How to reset control settings in Octopus?

    Open the application, select a profile Undertale, click Delete and create a new one. Alternatively, you can export the settings to a file and edit them manually (for example, if you accidentally assigned the wrong keys).

    Does this instruction work for Deltarune?

    Partially. Deltarune also supports keyboard controls, but has a different engine (GameMaker Studio 2). It may require separate settings in Octopus, since the location of the virtual buttons on the screen is different.