Switching components enable high-tech scarecrow

A timer and a light-dependent relay are key components of a mechanical bird scarer called the "Quiet Man", which is manufactured by Fox-Off.

Two Finder products - the 80.91 timer and the 11.71 light-dependent relay - are being used in the design of a mechanical bird scarer called the "Quiet Man", which is manufactured by Fox-Off.

There is considerable demand from farmers for an effective means of protecting grain, fruit and vegetable crops from damage by pigeons, which have proved resistant to conventional bird scarers.

The Quiet Man is noiseless, but flaps his arms at set intervals during daylight hours to scare away the birds.

The design has proved effective as a deterrent to rooks and gulls as well as to pigeons.

Key to the success of the scarer is the ability to operate from a 12V DC battery mounted in the base of the unit, with a typical battery life of 3 weeks.

The 80.91 is an asymmetrical recycling timer that operates at AC or DC voltages down to 12V nominal, with a rated DC power consumption of less than 1.4W.

The 80.91 is set to cycle on and off continuously, with the on and off periods independently adjusted to suit local conditions.

During the on period of the cycle, the timer switches a motor that drives the arm flapping mechanism.

The 16A contact rating of the 80.91 is particularly important for this application as it allows the timer to switch the motor directly.

The optional use of the 11.71 light-dependent relay also rated for 12V DC operation with a small externally-mounted sensor means that the unit is only activated during daylight hours, with a consequent improvement in battery life.

"Finder's range of relays is ideal for this application because of the low-voltage operation and low power consumption of these devices", commented Michael Aho, Managing Director of Fox-Off.

"In particular the high current rating of the 80.91, which allows it to switch the motor directly, has been critical to the success of the design".

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