HIDCO scheme to enable vehicle-sensitive street lamps
Kolkata: Housing Infrastructure Development Corporation (HIDCO) has taken up a unique pilot scheme to switch off and on one-third of the street lights until a vehicle passes though that stretch as a part of its drive to conserve energy. This is the first time such a project to save energy has been taken up in eastern India.
The stretch selected for the pilot project is Street 333, which is behind Biswa Bangla Sarani near Bagjola Canal and connects major arterial roads near Amity University and Alliah University. The estimated cost of the project is Rs 2 lakh. Senior HIDCO officials, including its chairman Debashis Sen was present when the demonstration was given by the Engineering wing of HIDCO on Thursday. The system has been working fine, Sen maintained. If successful, the scheme will be replicated in other parts of New Town, which is coming up as a 'green city'. There are 39 light poles, 80 LED street light assemblies and 52 bulbs on the street where the experiment will be carried out.
The main challenge faced by the engineers was to see that a person or cattle should not trigger the lights, which are supposed to be switched on only when a vehicle passes. So, traditional motion sensors, IR sensors or photo electric sensors had to be ruled out.
Also, any pressure sensitive trigger was ruled out because bullock carts can trigger the mechanism.
So, they made use of eddy currents, earth's magnetic field and recalled that vehicles are made of metal.
The sensor is based on a copper loop embedded underneath the surface of the road. One is installed at one end of the road on the entry lane, while the other one is placed on the other side of the road, on the entry lane as well.
When a vehicle enters Street 333, it disturbs the terrestrial magnetism link to the embed coil and generates an eddy current. This is amplified and used to switch on the unlit street lights.
It switches off after 5 minutes automatically through a timer mechanism, it being the average time required for a vehicle to traverse the 1 km length of Street 333.
The energy that is saved will be more than the cost of installation of the project. Once successful, the model will be replicated in other parts of New Town.