Even better is something like the Guardian Project's Haven(https://github.com/guardianproject/haven https://github.com/guardianproject/haven) which IIRC Snowden

Even better is something like the Guardian Project's Haven(https://github.com/guardianproject/haven https://github.com/guardianproject/haven) which IIRC Snowden contributed to. It's incredibly cost-effective to just buy an old Android phone (which comes integrated with multiple microphones, with good signal processing and noise cancellation), instead of building it with components. Haven is specifically designed for intrusion detection, and for preventing people from tampering with your laptop for instance by detecting activity on the Android phone's sensors.