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Author Topic: Sensors that can sense light?  (Read 951 times)

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Offline brightjoeyTopic starter

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Sensors that can sense light?
« on: November 11, 2010, 10:25:00 AM »
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?

Offline knossos

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Re: Sensors that can sense light?
« Reply #1 on: November 11, 2010, 10:51:32 AM »
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.
"Never regret thy fall,
O Icarus of the fearless flight
For the greatest tragedy of them all
Is never to feel the burning light."
 
— Oscar Wilde

Offline brightjoeyTopic starter

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Re: Sensors that can sense light?
« Reply #2 on: November 11, 2010, 10:59:45 AM »
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.
« Last Edit: November 11, 2010, 11:01:29 AM by brightjoey »

Offline waltr

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Re: Sensors that can sense light?
« Reply #3 on: November 11, 2010, 12:02:02 PM »
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".

Offline Soeren

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Re: Sensors that can sense light?
« Reply #4 on: November 11, 2010, 03:00:34 PM »
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?  ;)
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Please remember...
Engineering is based on numbers - not adjectives

 


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