6 Aspect - Searchlight Signal Driver (LM555)

  The circuit on this page is a 6 Aspect driver for a bicolour LED type Searchlight Signal. The available signal indications are; SOLID - RED, YELLOW, GREEN, and FLASHING - RED, YELLOW and GREEN. The circuit can also turn the signal OFF for approach lighting if desired.

  As this is a driver circuit, there is no actual input logic to select the signal indication. This will be added when it has been worked out.

  If you have any ideas on how such a logic system might function might work, please send an email with any details.

  The first circuit on this page is controlled by four toggle switches. Refer to the tables on the diagram for switch positions and the resulting signal indications.

6 Aspect - Searchlight - Basic Circuit

  Switches 1 and 2 control the colour that the signal will display, RED, YELLOW or GREEN. A fourth setting will turn the indication OFF and might be used for an Approach lighting input.

  Switch 3 determines if the signals is FLASHING or SOLID. As designed the flash rate is approximately 1 Hertz but can easily be changed.

  Switch 4 turns the Signal ON or OFF and could be used for an Approach lighting scheme. This switch is optional and could be left out of the circuit.

  The circuit is shown using three LM555 times but an LM556 could be used in place of two of these to reduce the parts count.

6 Aspect - Searchlight Signal With Simple Funtions

  The next diagram shows the same circuit but with comparator inputs in place of the switches. This circuit provides the basic functions as the "Simple Signals" circuits that appear on this site. The "Flash" function is not yet implemented.

6 Aspect - Searchlight- Simple Funtions

  Two outputs have been added to the circuit that could be used as part of the Flash logic. These are the "YELLOW INDICATION" and "RED INDICATION".

  Approach lighting is the default for this circuit and is disabled by grounding the 'Approach Input' terminal.

  The Flash funtion is activated by grounding the 'Flash Input' terminal.

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Please Read Before Using These Circuit Ideas

  The explanations for the circuits on these pages cannot hope to cover every situation on every layout. For this reason be prepared to do some experimenting to get the results you want. This is especially true of circuits such as the "Across Track Infrared Detection" circuits and any other circuit that relies on other than direct electronic inputs, such as switches.

  If you use any of these circuit ideas, ask your parts supplier for a copy of the manufacturers data sheets for any components that you have not used before. These sheets contain a wealth of data and circuit design information that no electronic or print article could approach and will save time and perhaps damage to the components themselves. These data sheets can often be found on the web site of the device manufacturers.

  Although the circuits are functional the pages are not meant to be full descriptions of each circuit but rather as guides for adapting them for use by others. If you have any questions or comments please send them to the email address on the Circuit Index page.

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