Automatic Emergency Light

Ugwu Gerald Obinna
Ugwu Gerald Obinna's picture
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Joined: Jul 19, 2017
Automatic Emergency Light
July 19, 2017 - 11:07am

Hello everyone, I'm new here. First I'd like to commend all of you for the amazing work you are doing. I've seen some circuits on my project but not one with all I need. I want to design an automatic emergency light with the following features ;

-transformerless power supply 

-makes use of LDR to stop bulb from shining during the daytime 

-has battery overcharge protection and cuts of supply when there  is prolonged power outage to prevent damage to battery  

-has red indicator for charging, green indicator for full charge and orange indicator for low battery 

B.Aswinth Raj
B.Aswinth Raj's picture
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Joined: Aug 16, 2016
Hi Ugwu,
July 20, 2017 - 4:30pm

Hi Ugwu,

Lets see how we can build it. I cant give you a complete circuit diagram but sure can give you some insights.

-transformerless power supply '

I think you are trying to keep thins compact by avoiding a transformer. In that case you should have to design your own SMPS which  can source +5V and 1A. There are also modules available online you can check on them if intrested.

-has battery overcharge protection and cuts of supply when there  is prolonged power outage to prevent damage to battery

Since you are asking for protection, it should be a Lithium battery I guess. You can use a normal 18650 Lithium cell based on the current rating of your battery. You can use the TP4056 module which can charge your Li+ from your Charger module and als protect it from over charge and discharger. This module will also give you the indication lights that you fish for.

-makes use of LDR to stop bulb from shining during the daytime 

Okay, you have to use Op-Amps for this. Compare the variable voltage from the LDR and compare it with a Preset voltage and trigger the LED based on it. You can also use the indication LED's the same way

 

Hope it helps!! All the best!!