A free app for Android, by AnchorFree GmbH.

Hotspot Control is a simple app that enables you to use your Android device as an access point to the Internet, without the need for a cellular data connection. The app lets you create an access point for your devices to share a wireless connection with each other. You can configure the access point name and password, and the connection will be made secure and stable, with a good signal and a low ping.

This is a free, open source, and fully compatible app, so you don’t need to worry about compatibility with your hardware or software. It works on most Android devices, including tablets, smartphones, and even on some Android-based tablet and smartphone models.