I built this circuit:+5V----Resistor 18kohm----+------PhotoTransistor------GND | | Arduino
can i use them for sensing visible light, not infrared light, too? does it make any difference concerning the sensibility?
(here, the resistor is before phototransistor and analog pin is also before transistor... why is this and whats the difference? is mine better than this?)
how is the best way to build a sort-of-distance-sensor with a phototransistor?
They come in different range values and are very simple to use.
Basically yes, sensors are matched to specific wavelengths, so to get the maximum sensitivity you have to use the right wavelength.
distance measurements using photo transistors are not very good, reliable or repeatable.
i never used the phototrasistor in this way ( in reverse), for me not sense. the best way in my opinion is tu use it in normal mode,means use it like 5v--------4,7k to 10 k resistor-------------Collector --------------emitter, then collector to arduino ( the junction in the coelctorsee the diagrams
how can i find out if i can use this sensor for "normal" daylight or lamplight, too?
sorry, what do you mean with "junction"? i'm no native speaker, so could anyone explain this to me?thanks a lot, jan
Quote(here, the resistor is before phototransistor and analog pin is also before transistor... why is this and whats the difference? is mine better than this?)Yes it is better than yours because it uses the voltage gain of the transistor, the other way round has no voltage gain and so is less sensitive.
Have I overlooked something?
we don't have any knowledge of the voltage at the base - it's not pinned out of the device
so I have trouble applying CE vs CC.