I am trying to use the wheel encoder mentioned in the circuit but somehow i can't manage to understand why there is a full voltage drop in the IR led and why the resistors are not limiting that voltage drop, considering that in "ohmic" terms my circuit should work.
I would like somebody to help me pin what i am doing wrong
The datasheet is http://sensing.honeywell.com/index.php?ci_id=50399
In the electric characteristics the datasheet says that the forward voltage should be 1.6 V@20mA and the supply of detector should be between 4.5 and 5.5V@7mA
So to use the resistors i have at hand the circuit is in the following attachment. For the IR led i connected it to a 5V source with a 220hm resistor and to the receiver 47 + 47 Ohm resistors.
Also i am connecting the A and B channel outputs to an atmega328 directly as the datasheet says the HOA0901 has internal pullups. I also set the atmga328p in input mode.