Microprocessor Based Street Light Control System  
Civil Twilight Switcher

It has been observed that street / yard lighting in many areas is not properly controlled, resulting in wastage of electricity and reduced life of lamps due to wasteful burning at unwanted times also. Since these lamps work mostly during peak load hours, it attracts higher tariff, consequently leading to huge energy bills.

Simple energy conservation techniques can be employed by keeping lamps ON only when required and OFF when sufficient sunlight is available. Also, by controlling the number of lamps in operation for different timings, one can save considerable energy.

CTS is a microprocessor-based system, developed with the above need in focus and works by making use of the ‘Civil Twilight Timings’ (Sunrise & Sunset) of a particular place. It is programmed to take into account the civil twilight timings which depend on the latitude and longitude of the place of installation.


  • Saves precious peak-power through precisely programmed ON timings.
  • Seasonal settings throughout the year.
  • Highly accurate digital clock controls the on-off timings.
  • Manual override facility.
  • Access through a dedicated hand held terminal or laptop for checking time, date etc.
  • Wide range of load connectivity through contactors.
  • Can be connected to a PC for monitoring and controlling. (Optional)
  • Three phase and single phase versions available
  • Cyclic shut off feature for increased lamp life and energy saving in 3 phase street-main circuits.
  • Power consumption as low as 5 watts.
  • Long life lithium battery backup(more than 7 years) for Real Time Clock
  • Operates even with one phase in 3 phase circuits
  • Highly reliable and maintenance free

This technology has been successfully demonstrated and still being used regulary
at Perealassery Panchayat in Kannur Dt of Kerala.

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