There are a few different techniques you can use to receive a Bluetooth signal in a tiny robot. One option is to use a Bluetooth module, which is a small electronic component that can be integrated into your robot's design. This module will allow your robot to communicate with other devices, such as a cell phone, via Bluetooth.
Another option is to use a microcontroller, such as an Arduino, which can also be equipped with a Bluetooth module. The microcontroller can receive the Bluetooth signal and then control the movement or actions of your tiny robot.
You could also consider using a wireless receiver that is specifically designed for receiving Bluetooth signals. This would eliminate the need for a separate module or microcontroller, making the design of your tiny robot simpler.
Ultimately, the technique you choose will depend on the specific capabilities and design of your tiny robot. It's important to carefully research and plan out your design to ensure that the Bluetooth signal can be received and utilized effectively.