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How to dim a lamp using PIR sensor or microcontroller?

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aegis

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hello
i just started my project using PIR sensor to controlling light, turn on /off and dimming, how can i dimming the lamp, instead turn on/off using PIR sensor controller IC, should i use a µController ?
 

throwaway18

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dimming the lamp

If you use a dimmer that has a variable resistor to control the brightness you could just use a relay to switch between two different resistors to give different brightness levels.
 

philba

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dimming the lamp

or better yet, use a TRIAC to control the lamp. Look up opto isolators like the moc30xx line which allows digital control. Also look up phase control of TRIACs to figure out how to dim the lamp. Yes, I would use a small uC - you only need a couple of pins.
 

crowinu

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Re: dimming the lamp

philba said:
or better yet, use a TRIAC to control the lamp. Look up opto isolators like the moc30xx line which allows digital control. Also look up phase control of TRIACs to figure out how to dim the lamp. Yes, I would use a small uC - you only need a couple of pins.

i agree with you philba, but on the uc or piun usage it depends on what you really want. i did some similar progject for my 2ndyr of my course , i used the pic16f877 and i used a triac to control the bulb, i was controling 230V ac bulb.

@aegis, becarefull to isolate mains from dc, and also becarfeull to your self when testing :)

crowinu
 

philba

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Re: dimming the lamp

crowinu said:
philba said:
or better yet, use a TRIAC to control the lamp. Look up opto isolators like the moc30xx line which allows digital control. Also look up phase control of TRIACs to figure out how to dim the lamp. Yes, I would use a small uC - you only need a couple of pins.

i agree with you philba, but on the uc or piun usage it depends on what you really want. i did some similar progject for my 2ndyr of my course , i used the pic16f877 and i used a triac to control the bulb, i was controling 230V ac bulb.

@aegis, becarefull to isolate mains from dc, and also becarfeull to your self when testing :)

crowinu

I'm not sure there is a disagreement - can't really tell.

to be a bit more complete, you need 1 pin only to turn on or off, 2 pins and timer to effect dimming. On/Off is easy. For dimming, use an opto isolator to drive the triac from logic signals (i.e. output pin). use an opto isolator to detect zero crossing (via an input pin). Use a timer to decide how long you delay turning triac on after zero crossing. The longer the delay (up to 1/2 AC cycle), the lower the power to the load (lamp in this case). this is described all over the internet.

bonus points for figuring out how to make the delay so that the power to the load is linear. for example, what is the setting for 20% power? - it's not 1/5 of the half cycle.

more bonus points - What kind of noise does this circuit produce? What is the source of the noise? how do you avoid noise from this circuit?
 

sunsuprim

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Re: dimming the lamp

hello
i just started my project using PIR sensor to controlling light, turn on /off and dimming, how can i dimming the lamp, instead turn on/off using PIR sensor controller IC, should i use a µController ?

dear sir,
please send me the circuit for ON/OFF control of the light. pleassssssssssssssssssssssssssssssssseeeeeeeeeeeeeeeeeeeeeeeee
it's very urgent
Mod: We dont enetertain private sharing. Anything can be shared on the open forum for the benefit of all the members. If your key board buttons are stuck up, trash it and use a new one when you login the next time.

himanshu aya
 

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