Wireless Battery-Free

RTH has developed wireless link systems that require no batteries to function. Electromagnetic signals are converted directly to acoustic signals. One of the embodiments is a wireless communications earplug that is especially well suited for double hearing protection applications. The earplug has been tested favorably to military specifications regarding electromagnetic interference (susceptibility and radiation) and has been tested in the field. This technology has been licensed to a major manufacturer for the military and national defense markets, except for the aircraft carrier environment. The carrier deck markets and commercial markets are available. Applications for this technology include: aricraft pilots/crew (military and general aviation), aircraft maintainers, ground troops, armored vehicle crew, motorsport helmets, ski helmets, football helmets, chem-bio headgear, first responder headgear and others. 
Two utility patents have issued, and one design patent has issued. Continuations have been filed including a continuation in part disclosing additional embodiments of the inventions. A wireless transmitter invention is also patent pending.

Click on the images to see the title page of patents and on the links below to download full patents.

Wireless communications headset system employing a loop transmitter that fits around the pinna

A wireless communications earplug that is battery-free and a loop transmitter that fits around a user's pinna. This invention may be installed in communications headsets to provide double hearing protection. The battery-free communications earplug never needs to be recharged, nor does it require a battery. The invention can be retrofit into existing headsets and helmets, such as aviation headsets.


Earplug design patent particularly useful for wireless communications earplug applications.

Wireless earplug with improved sensitivity and form factor

Continuation in part of US 8,688,036. An embodiment of a wireless communications earplug with improved sensitivity that is battery-free.

Transmitter with improved sensitivity and shielding

Magnetic induction transmitter. Can be used with RTH battery-free communications earplugs. Foreign patent applications have been filed and are pending.

5. Pending

Magnetic field antenna

Continuation in part of US 8,688,036. This patent describes another embodiment of a wireless battery-free communications earplug. 

6. Pending

In-ear noise dosimeter

John Parkins,
Mar 6, 2014, 1:19 PM
John Parkins,
Apr 3, 2014, 1:13 PM
John Parkins,
Apr 8, 2014, 7:28 AM
John Parkins,
Jul 31, 2015, 2:29 PM