Sensors that can sense light?

[brightjoey]

HIE robot friends!

I'm going to create a very simple robot that can follows light . I checked around youtube with alot of examples and most of them look very impressive.

So I went out to buy some light sensors and asked around in electronic shops and what they only shown me was some photocell/phototransistor that cost like 1/2$ and the range looks so pitiful, sensing light only when a light source is about 5cm away. I wanna know any other kind of light sensor that can sense even further, preferably 1m away?

[knossos]

A standard LDR (Light Dependent Resistor) makes a decent light sensor, is inexpensive and is most likely what you are looking for.  You can pick up this 5-pack for about $3 from your local Radioshack if you live in the US.  You can also search online stores such as Digi-Key, Mouser, or others for photoresistors.  This randomly selected photoresistor from Digi-Key is about $1.58.

[brightjoey]

A standard LDR (Light Dependent Resistor) makes a decent light sensor, is inexpensive and is most likely what you are looking for.  You can pick up this 5-pack for about $3 from your local Radioshack if you live in the US.  You can also search online stores such as Digi-Key, Mouser, or others for photoresistors.  This randomly selected photoresistor from Digi-Key is about $1.58.

This was the one I looked from the local electronic shop and the shop owner shown me it connect wif a circuit with an LED, and I can't see a significant change on the range of the sensor, I don't mind paying more(not that I want to, but if I must) if the sensor can sense really really far away light source. Or is there any other alternative? As long as It can sense a far away light source in a dark environment I'm happy.

[waltr]

If you are trying to detect a small, far away light source then use a lens (telescope) to amplify the distance light.

Try google search on "optical communications receiver".

[Soeren]

Hi,

This was the one I looked from the local electronic shop and the shop owner shown me it connect wif a circuit with an LED, and I can't see a significant change on the range of the sensor,

The sensitivity can be very low if not used correctly and it's hard to discuss a circuit that you don't know (or how it was used), so let's forget about that.
LDR's can be very sensitive if used properly.

[...] if the sensor can sense really really far away light source.

Well, the sun is really really far away 

You have to define things a bit more precise, so how bright is the source and how far away is it?

Or is there any other alternative? As long as It can sense a far away light source in a dark environment I'm happy.

How dark?