GB2528695A - Turnstile indicator - Google Patents

Abstract

A turnstile having an LED indicator (5 a-c) and means for controlling the intensity of the LED so that the intensity progressively increases on start up to a working intensity. The LED being controlled to fade out from working intensity when switching off. The intensity being adjusted using a ramp function to simulate an incandescent bulbs functioning, the adjustment may be through a pulse wave modulation arrangement. The LED indicators may be arranged to display messages, display various colours and/or flash. The indicators may be an individual LED or group of LEDs. Preferably the time between being switched on and reaching maximum intensity is 200 ms to 500 ms. The LED is operated to simulate a standard light bulb reducing the fatigue of those within sight of the indicator.

Description

Turnstile Indicator This invention relates to turnstile indicators.

S Turnstiles, have barrier mechanisms such as retracting wings, swing barrier or rising arm barriers. They also often have indicators on them, which are generally LED indicators. These may be lane indicators providing information to a user such as standby, proceed through a lane, visitor entry authorisation and alarm states and may flash colours or change colour when actuated.

With present systems, the lane indicators are switched ON and OFF fairly frequently and the switching of LED indicator colour and intensity is seen by the eye as instant. This can be considered to be quite severe by some users. The LED is either instantly switched ON to its full intensity or is OFF. The turnstiles may be in a room or environment with a relatively low level of ambient lighting and thus rapid changes of the indicator output, without allowing the eye to adapt to it, may be undesirable.

The present invention arose in an attempt to provide an improved method for controlling LED indicators on turnstiles.

According to the present invention there is provided a turnstile having an LED indicator, and means for controlling the intensity of the LED indicator such that the intensity progressively increases on start-up to a working intensity.

Means may be provided for adjusting the intensity of the LED indicator with a ramp function, to give the appearance of the light bulb illuminating.

Means may be provided for operating the LED indicator by a pulse width modulation (PWM) signal in which the progressive increase in intensity is achieved by adjusting the mark space ratio.

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 shows, schematically, turnstile apparatus; S Figure 2 shows a rise in intensity of an LED indicator system when turned ON; Figure 3a and 3b show PWM signals having different mark space ratios; and Figure 4 shows, schematically, an LED indicator with a processor.

Figure 1 shows schematically a turnstile comprising a pair of pedestals 1, 2 housing control electronics, hardware, software and so on and defining between them a lane through which a person must pass. The turnstile includes barriers mounted to block or allow passage through the lane and infrared or other detection apparatus for detecting the passage of persons through the lane.

The turnstile apparatus may include a display 4, entry/exit authorisation means such as card readers and so (not shown) and one or more visual indicators in the form of LED indicators Sa to Sc. These are shown purely schematically in the figure and may be in many different dispositions or locations. These lane indicators may signal various information to the user such as standby, an instruction to proceed through the lane, visitor entry authorisation, an alarm state and may be arranged to display various colours such as white, green, red or other colours. They may also flash if desired and may have other visual characteristics. The indicators may be individual LED5 or groups of LED5.

These may be controlled in any manner and Figure 4 shows schematically an LED indicator S connected to a controller 6 by connectors 7a, 7b.

The controller 6 is arranged so that, when the LED is first turned ON, instead of simply switching the LED to full power immediately, it ramps up the intensity, giving the effect of a fading in. Similarly, when the LED is turned OFF it may also phase out the LED if required.

Figure 2 is a plot of intensity versus time and between times TO and Ti the LFD is not turned ON. It has minimum intensity. It is turned ON at time Ti and its intensity is increased progressively between times Ti and T2 to a maximum. At T2 the intensity is at the maximum and the LED stays at that maximum and turned OFF. The reverse process S may occur, if required, when the LED is turned OFF or it may be turned instantaneously OFF. A typical rise time between Ti and T2 may be between 200 ms and 500 ms, but values outside this range may be used.

The LED indicator is operated by a pulse wave modulation (PWM) generator which generates a PWM signal. Light intensity for an LED powered by such a signal may be altered by altering the mark space ratio. Figure 3a shows a signal having relatively low mark space ratio so that the period of time of a spaces is much longer than the period time having mark M. The drive signal to the LED is increased between times Ti and T2 to reach a ratio as shown schematically in Figure 3b, for example, in which M is considerably greater than Sand therefore the intensity is greater.

Thus, an indicator lamp controller is provided with algorithms for operating the PWM signal to simulate a ramp function of a light bulb.

In embodiments, an LED indicator system is operated to simulate the appearance of a conventional light bulb which has a rise and decay of light intensity, for turnstile application. This has the advantage of reducing fatigue in persons within sight of the turnstile using such soft start techniques.