Let's Make Robots!

LDR vs Ir Phototransistor

Hi  Everyone

I'm doing research for my first bot from scratch. I was hoping someone could point me to a good source of info on the advatages/disavantages of using LED & LDR vs Ir with Phototransistor for proximity sensors.

My basic goal for them is to have an edge detector in each corner and a line following array. I thought the LDRs would a simple and cheap approach but was surprised to see how cheap this Ir LED & Phototrasistor set was.

So basically effectiveness vs cost vs ease of use.

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You should go with the LED/phototransistor pair. LDRs are slow to respond to changes in light and might hamper your line following plans.

another difference is that LDR's will be influenced by all kinds of light, whereas IR sensors will tend to ignore light
that isnt IR.

the low cost of the set might be due to it having a very short range, it seems price is somewhat proportional to range,
so considering the aplication you can just get the cheapest ones.

i recently made a line sensor module with regular LEDs and LDRs and although it sucks for various reasons,
i am definetly using IR on my next attempt.

I am aware that the LDR would be more susceptible to ambient light and need to be shrouded, I guess I'm looking more for disadvantages of the phototransistor (if any)

they are 57 cents each at arrow.com, i bought a bunch and recommend them

Yup, I will pick some uo to play around with. Thanks everyone!