Blue Switch is an iPhone app developed by Vitalij Schaefer that allows you to control a 2, 4, or 8 Channel Relay Module Bluetooth BLE with your iPhone or iPad. This app is available for free and falls under the Utilities & Tools category.

To use Blue Switch, you will need one of the following modules: "2 Channel Relay Module Bluetooth BLE," "4 Channel Relay Module Bluetooth BLE," or "8 Channel Relay Module Bluetooth BLE." These modules can be purchased from various online shops. Simply search for them using a search engine.

You can connect any number of modules to the app and assign them different aliases to easily identify and use them. For example, you can name the modules "Relay 1," "Relay 2," "Electronic lab project," or "Ambient Light." Additionally, you can set an alias for each relay.

By default, the password for these modules is "." However, for enhanced security, Blue Switch allows you to change the password. The new password must be eight digits long.