I have a pair of IR transmitters and receivers, but I have found that the brightness of the transmitter is very low, so that I can't use it to detect an object in front of them.
What should I do?
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Sign up to join this communityI have a pair of IR transmitters and receivers, but I have found that the brightness of the transmitter is very low, so that I can't use it to detect an object in front of them.
What should I do?
IR transmitter LEDs are literally just LEDs that emits Infrared Light which is not visible to the human eye. That being said, IR LEDs behave very similarly to regular LEDs and therefore to increase the brightness you need to increase the Voltage it is receiving, just like you would do with a regular LED.
But the problem with LEDs is that they drain current and that's why we use resistors,to protect our electronics(i.e. Arduino).
So to recieve maximum voltage you can reduce the resistance of the resistor (let's say 220ohm or even 100ohm).
Forgot to mention that the correct wiring of LEDs to an arduino is as follows:
5V pin(or digital pin set to high) -> Anode leg(longer) of LED -> Resistor(connected to shorter leg :3) -> ground pin
If you aren't at the current limit of either the IO pin (40mA) or the LED (usually around 30mA) you can increase the current as far as the lower of those. That can be done by reducing the value of the resistor you are using with the LED or using a higher current drive circuit.
However, just having an LED turned on all the time is not a good way of using it - you are constantly fighting against the background light.
Instead the LED needs to be pulsed on and off using PWM at a very high frequency (typically 30-50kHz) and you need to detect that pulsed light with the receiver.
This is usually achieved by using a high-pass (or band pass) filter and amplifier on the receiver.