GB2181919A - Key fob with light actuated audible alarm - Google Patents

Abstract

The fob comprises a casing with an eyelet for attachment to a key ring, the casing containing a light sensitive element CdS, a battery and a buzzer which is sounded when the element is exposed to light. The fob is said to be useful to signal theft or to aid location if keys are mislaid. <IMAGE>

Description

SPECIFICATION Photo-sensitive keychain alarm This invention relates to a keychain with an audible alarm activated by light.

Keychains are generally comprised of a metal ring onto which keys can be attatched, a conecting chain & a fob. The primary function of the fob is to prevent the keys being lost or misplaced. This invention incorporates a light sensitive alarm in the fob section. The purpose of this audible alarm signal is to enhance the function of the fob; namely to prevent the loss of the keys attatched.

A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawing. The fob may take the form of a rectangular slab as shown.

Figure 1 shows the top side with a grill to facilitate loud emmission of the audio alarm signal. There is a molded bar section for attatching a chain with a keyring or a clip for banknotes, a wallet or other items.

Figure 2 shows the end opposite to the molded bar where a small appeture reveals the surface of the cds, light sensitive component. This appeture may be covered by a transparent window to protect the cds.

Figure 3 shows the top side with the outer cover removed to show the printed circuit board with the cmos bonded on, battery & BR< alarm buzzer.

When the keychain is exposed to visible light, after being in darkness, the cds generates an electrical current which triggers the cmos to activate an audible melody alarm. A small 1.5v silver oxide battery provides the power source. The alarm will sound for between 15 & 30 seconds dependant upon the type of cmos used. Thus misplaced keys can be located by making the room dark and the light. The alarm will sound if the keychain falls from, or is stolen from, a pocket or handbag.

In darkness inside or outside the keychain alarm will respond to a flashlight or any other light source of sufficient intensisty.

1. A keychain and fob incorporating an audible alarm which is activated by visible light.

2. A fob, chain & multipurpose clip incorporating an audible alarm which is activated by visible light.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (2)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Photo-sensitive keychain alarm This invention relates to a keychain with an audible alarm activated by light. Keychains are generally comprised of a metal ring onto which keys can be attatched, a conecting chain & a fob. The primary function of the fob is to prevent the keys being lost or misplaced. This invention incorporates a light sensitive alarm in the fob section. The purpose of this audible alarm signal is to enhance the function of the fob; namely to prevent the loss of the keys attatched. A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawing. The fob may take the form of a rectangular slab as shown. Figure 1 shows the top side with a grill to facilitate loud emmission of the audio alarm signal. There is a molded bar section for attatching a chain with a keyring or a clip for banknotes, a wallet or other items. Figure 2 shows the end opposite to the molded bar where a small appeture reveals the surface of the cds, light sensitive component. This appeture may be covered by a transparent window to protect the cds. Figure 3 shows the top side with the outer cover removed to show the printed circuit board with the cmos bonded on, battery & BR< alarm buzzer. When the keychain is exposed to visible light, after being in darkness, the cds generates an electrical current which triggers the cmos to activate an audible melody alarm. A small 1.5v silver oxide battery provides the power source. The alarm will sound for between 15 & 30 seconds dependant upon the type of cmos used. Thus misplaced keys can be located by making the room dark and the light. The alarm will sound if the keychain falls from, or is stolen from, a pocket or handbag. In darkness inside or outside the keychain alarm will respond to a flashlight or any other light source of sufficient intensisty. CLAIMS

1. A keychain and fob incorporating an audible alarm which is activated by visible light.

2. A fob, chain & multipurpose clip incorporating an audible alarm which is activated by visible light.