Thor Guard Voice of Thor

Thor Guard Voice of Thor (VOT)
Company	Thor Guard Inc.
Produced	1973-Present
Type	Omnidirectional Pneumatic
Sound output	113 dB @ 10 ft
Voltage	12 V DC
Documentation	Product sheet

The Voice of Thor (VOT) is a pneumatic lightning warning siren system that can be found at golf courses, parks, beaches, pools, and other similar public areas. It works in tandem with Thor Guard's lightning detection systems as a way to warn the public of lightning strikes. The system is usually activated by a lightning sensor (usually next to the siren), and can be tested by a button. Thor Guard has advanced technology so that the device can detect approaching storms from miles away.

Design

The Voice of Thor system was introduced in 1973. The siren unit consists of two air compressors, and a varying number of PVC pneumatic air horns (usually six). The two compressors are housed underneath the siren's large dome-shaped rainshield, which also covers the horns. Each compressor is tied to up to three tubes which supply pressurized air to the horns. Each horn, as well as the compressors are bolted to a cylindrical plate. The entire unit is held up by a PVC pipe that contains the siren's wiring and conduit, with the controller typically being mounted directly below the siren. The siren is typically paired with orange flashing Whelen 51 Series LED strobe lights to provide visual notification. The entire system runs on 12 V DC, and can be charged with 120 V AC or a 30 W solar panel.

The system can produce two signals:

Red Alert (Warning): One 10 second continuous blast

All clear: Three 5 second blasts

Trivia

• Although the Voice of Thor itself is considered a siren, it is actually made up of a bunch of air horns instead.
• The horns are built in Stebel, Italy.
• These sirens are often mistaken for being electronic, but are in fact pneumatic.