Guardian Dock — Phone Privacy Dock for Confidential Conversations

Every phone on a meeting table can record. In a board discussion, a client consultation or an HR or medical conversation, one tap starts an audio or video recording, and an app can switch on the microphone or camera without the owner noticing. Asking visitors to leave their phones outside feels rude; letting the phones stay on the table puts the conversation at risk.

A good answer had to be polite: something a host offers guests, like checking in a coat, not a demand. It had to stop audio and video capture together, because covering only the microphone or only the cameras still leaves a recording possible. It could not harm the phone, block calls, mobile signals or Wi-Fi, or affect any phone that was not placed on it. And it had to work on a table with no socket nearby, and charge the phone so guests have no reason to take it back early.

Guardian Dock gives each phone a place to rest during a private conversation. With the phone on the dock and Privacy Mode on, piezoelectric transducers at the top, bottom, front and back surround it with inaudible ultrasonic sound that keeps shifting in frequency. This ultrasonic microphone masking leaves the phone's microphones picking up only noise, so the phone can't make a usable recording. Non-adhesive covers slide across the front and rear cameras, and a Qi-compatible coil charges the phone at up to 15 W. The effect stays with the docked phone: calls, mobile signals and Wi-Fi keep working, other phones in the room are not affected, and the phone itself is not harmed.

Inside, a low-power AVR microcontroller sends frequency commands over SPI to a direct digital synthesis (DDS) waveform generator and runs a pseudo-random sweep, so the signal never settles on a single fixed tone that a phone's adaptive noise suppression could filter out. The square-wave output is buffered and fed to a Class-D amplifier, which drives the transducers through impedance-matching output stages. Wireless charging is a separate subsystem with its own switch, isolated from the ultrasonic electronics. A 6000 mAh Li-Po battery and power-management IC supply regulated 3.3 V and 5 V rails with over-voltage, under-voltage and thermal protection, and a DC barrel jack with pass-through lets the dock run while it recharges.

1. Step 1PlacePut the phone on the dock and slide the covers across its front and rear cameras.
2. Step 2ActivatePress Privacy Mode to start ultrasonic microphone masking; an LED confirms it is on.
3. Step 3ConverseThe phone stays parked and charging, and it can't make a usable recording.

• Ultrasonic microphone masking from the top, bottom, front and back
• Constantly shifting signal that a phone's noise filtering can't remove
• Sliding covers over the front and rear cameras
• Qi-compatible wireless charging at up to 15 W
• Affects only the docked phone; calls, signals and Wi-Fi keep working
• Up to 4 hours on battery with privacy mode and charging both on

• Patent application published in India (IN202631006318) on 10 April 2026
• Designed and built in-house by Aeonix: custom PCB, signal firmware and dock enclosure
• One 6000 mAh battery runs privacy mode and wireless charging together for up to 4 hours
• Works with Qi-compatible iPhone and Android phones, with no app to install and nothing for the visitor to set up
• Does not harm the phone: the sound is above human hearing and the camera covers are non-adhesive