150 ohms is the minimum and larger resistors can also be used.
Anything over that would keep my current under 50mA, no matter what the resistance of the diode might.
In any case, I had proof the diode was working, so now on to the photo-transistor.
Anything below 600 would.The value will be based on the voltage and the LED/interrupter used.This is good for detecting water drops because it has a 15mm gap size.The catch however was getting it to work.In reality, I should have started with 5v and worked backwards; realizing that R V / I, I could have said R 5v /.05A, or 100ohm.There are various different kinds of photo interrupter, different shapes and different sizes but all do the same job.It connects to the camera control device by a standard.5 headphone/audio lead.Sensors, mORE details, mOC7811 is a slotted Opto isolator module, with an IR transmitter a photodiode mounted.With that part ready, my first goal casino online gratis 96 3 was to scour the Internet for examples of these types of projects.As usual, I expected easy but got anything but.Which equals 150 ohms.Specifications, size: Refer to the image below.Some with 5 pins, some with 4 pins.Slot depth: 7mm, applications, dC motor position / velocity control.
Most LEDs have a forward voltage of around 2v and use about 20mA (or.02A) of current so when using 5V supply and a 3V photoisolator we have: R (5-2) /.02A.

To get started I created a small test circuit with just the interrupter.I saw a reference to using a 150 ohm resistor, so I used an available one (180ohm) and connected it to power.The interrupter/optoisolator below is a Liteon LTH-301-32.Since I used the LTH-301-32 which is 5V I didnt need a large resistor and used a 100 ohm resistor I had on hand.When the LED was on, the phototransistor would conduct; when it was off (or something blocked the light falling on the transistor) it wouldnt conduct.In an early version of the camControl device (before the dropController) I used an interrupter/optoisolator to detect the water drops.So I gave up and attacked it another way.This change in the logic level can be sensed by the microcontroller or by discrete hardware.
Remove the light and the current stops.