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i want a bulb/led to light up with an intensity dependent upon the amount of light that hits the analogue light sensor...do i really need arduino or any programming? , or can i just connect the battery ,the light sensor and the bulb in a simple circuit??


5 Replies

bwrussell (author)2012-10-05

It's projects like this that make me wish the Digispark was out now. Simple, as long as you can write basic code, and cheap.

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rickharris (author)bwrussell2012-10-06

£1.80 picaxe 08m will do this easily in a few lines of basic code! the pwm for the output is the hardest part.

Personally I would put multiple leds on separate outputs to vary the light level then it becomes easy


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Jack A Lopez (author)2012-10-05

I think a microcontroller is kind of overkill when all you need is a single gain connecting an analog in to an analog out. 

Especially in the case when the gain you want is exactly 1. 

Any of you kids ever heard of a op-amp wired as a voltage follower?

A single transistor wired as an emitter follower?

Anyone? Anyone? Bueller?

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frollard (author)Jack A Lopez2012-10-05


Also depends on the type of 'led bulb'. Anything closing on a watt will need a driver circuit, and a lot of driver circuits will try to compensate for any dimming you do outside of that circuit, burning themselves out.

If just a simple single led strand on a dc supply + resistor, your emitter follower is the perfect solution.

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rickharris (author)2012-10-05

Simple? Probably not although that depends on your experience.

i would say the easiest approach is the micro controller but that is going to be software complicated,

A comparator will do something such as you want look at the data sheet for the 741 for example.

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