I have a dim infrared light that blinks on an infrared phototransistor which in turn blinks a standard LED. Unfortunately, the LED does not blink bright enough. I can't increase the light that the infrared gives off. I'm using a 12 volt DC power supply. Is there a way to enhance the brightness of the LED another way?
I've tried without using a resistor with no improvement.
I'm not using an Arduino for this.
Buy a higher powered IR LED... Simple
Doc
Or increase the gain with another transistor, or a darligton transistor
Is there a way to enhance the brightness of the LED another way?
You could direct (focus) more of the energy that is emitted using optical means, but be aware that some substances that are transparent to visible light may block IR (and vice versa), and the focal point of any lens will be different between IR and visible wavelengths.
First I'd have a look at the datasheets / specifications for the phototransistor and the LED - what is the maximum current the phototransistor can carry? What is the maximum current the (visible) LED can take?
Then measure the actual current that gets through the phototransistor.
Perhaps the phototransistor is already doing its best and amplification is needed?
Perhaps the IR LED can be brighter to get more current through the phototransistor?
Perhaps the visible LED is already carrying enough current and you need a higher current one or a more efficient one?
Note that some LEDs are much brighter than others for the same current - if yours isn't an ultra-bright variety then replacing
it would be a simple fix. Most small LEDs are rated around 20 or 25mA, ultra-bright ones are pretty bright at that current!
If the issue is the IR LED not being bright enough then you can improve the optical path, add more IR LEDs (or brighter ones),
or add amplification after the photo transistor (another transistor in darlington configuration with the phototransistor perhaps).
There are also photo-darlington's available I believe.
I've tried without using a resistor with no improvement.
Your LED is probably, already dead.
I's not clear what you trying to achieve, for simple IR remote control you better to use "modulated" IR beam, which doesn't require much power to compete with environment.
If "modulation" is new word for you, than start with :
Infrared Keychain Remote Control - COM-10280 - SparkFun Electronics and IR Receiver Diode - TSOP38238 - SEN-10266 - SparkFun Electronics
I doubt the LED is dead if its dim - the phototransistor is limiting the current I think - photodiodes and transistors allow current roughly proportional to illumination and are reasonable current sources/sinks.
May be I misread OP, my impression was
I can't increase the light that the infrared gives off.
that he trying to increase IR emmision outputs connecting IR transmitting LED to +12V w/o resistor. Anyway, it doesn't hurt to give better description on hardware when posting question like that.