Author Topic: motion night sensor power on leds  (Read 457 times)

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Offline panayiotis kasapisTopic starter

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motion night sensor power on leds
« on: October 01, 2013, 02:06:33 PM »
dear friends
i need help with a project!!!!!!!
i want to make a circuit to work at night when there is motion and power several leds.
i buy       
an ldr   
some npn transistors   bc547   and 2n3904 
some resistors 100k     
boost regulator 3v to 5
pir sensor
i connect the ldr to 2 npn bc547 transistors and i test it ok!
then i connect the - from npn transistor to the - of the pir and the + of the pir to + and the out of the pir to a single led. it works but the light is low.
if i connect the pir output to a 2n3904 transistor and after to the led the led is brighest! but when i connect the current to the voltage booster and to all leds the light is very low!
the problem is the 3.3v from the pir output. i need 5v to work my leds
what i must do?
thanks

Offline panayiotis kasapisTopic starter

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How can I amplify PIR output to 5V
« Reply #1 on: October 02, 2013, 12:41:24 PM »
dear friends
i need help with a project!!!!!!!
i want to make a circuit to work at night when there is motion and power several leds.
i buy       
an ldr   
some npn transistors   bc547   and 2n3904 
some resistors 100k     
boost regulator 3v to 5
pir sensor
i connect the ldr to 2 npn bc547 transistors and i test it ok!
then i connect the - from npn transistor to the - of the pir and the + of the pir to + and the out of the pir to a single led. it works but the light is low.
if i connect the pir output to a 2n3904 transistor and after to the led the led is brighest! but when i connect the current to the voltage booster and to all leds the light is very low!
the problem is the 3.3v from the pir output. i need 5v to work my leds
what i must do?
thanks

Offline jwatte

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Re: motion night sensor power on leds
« Reply #2 on: October 02, 2013, 07:51:40 PM »
You need to post a schematic, and refer to the schematic in your problem statement.
I cannot picture what you've done and try to debug it without that.

 


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