How can the emitter have an output if you connected it to ground?.....................
This is output taken from the emitter
I have changed the resistor on the LED it has made an improvement to the peak to peak voltage. I dont know why but I get a good output from the emitter. Even though it is connected to ground. I think it may be a pnp or npn thing.We will flip the signal once you get a strong one. 33k is fine for now. Now change the resistor on the LED
Take a photo of your setup and post it.
Now one from the top with better light. And the whole board.View attachment 98305
The left is the infrared emitter, with a resistor to ground. 100 ohms. The other resistor going into it is to clean up the input square wave, and is connected to the other pin.
The phototransistor left pin is the flat edge (emitter), it goes to bottom rail which is 0. The other pin goes to 5v via the 33k. The output is from the emitter in this pic but I have moved it to the collector,
It's switching noise. You need to decouple the power supply.Even though it is connected to ground. I think it may be a pnp or npn thing.
Right sorry could you explain what that means ?. My power supply is two crocodile clips one to positive and one to negative, how do I decouple this ?It's switching noise. You need to decouple the power supply.
Typical reaction time is in the sub-us territory so 4Khz shouldn't be a problem - the remote controls for example run at ~10x of that.at this frequency the output of the phototransistor is nothing like a square wave.
Put two caps across the power supply; 0.1uF for high frequency decoupling, and an electrolytic for low frequencies.Right sorry could you explain what that means ?. My power supply is two crocodile clips one to positive and one to negative, how do I decouple this ?
You will need some amplification to lower the output impedance. Putting the load on the emitter will also help improve speed. Litton I think has an app note on that.schematic below
Thats made it a bit better, How can I flip it ?Put two caps across the power supply; 0.1uF for high frequency decoupling, and an electrolytic for low frequencies.
Ok, now aim the two devices (IR LED and the phototransistor) right at each other. Like you want to shoot from your gun down the barrel of your enemy's gun. The remote control for your tV works very poorly if you stand on the side of your TV. Point right at it!
I have been pointing them at each other, even though in the pic they look upright !,Ok, now aim the two devices (IR LED and the phototransistor) right at each other. Like you want to shoot from your gun down the barrel of your enemy's gun. The remote control for your tV works very poorly if you stand on the side of your TV. Point right at it!
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