Use of emitter control in new QTR sensor

Hi guys,
I have bought the new QTR sensor, and here there are 2 CTRL pins, what can be they used for?
I understand they can be used to turn on / off alternate emitters, but I don’t understand why?
I mean, I have used old red ones, they had emitters always on and I never had a problem with them…what are the use cases for using CTRL pins (excluding power consumption)?

One that is mentioned in the product page and I don’t get is: “…which gives you extra options for detecting light reflected at various angles. See the “Emitter control” section below…”
are there any other use case?

Thanks in advance :blush:


By default, the emitters are all connected together and fully powered on our new QTR sensor boards, but the boards can be modified so that the odd and even emitters can be controlled separately, and the power to the emitters is adjustable.

One case where it might be useful to control the odd and even emitters separately is when you need to identify a more precise location for where something is along the array than what you can get with the emitters all connected together. Comparing the readings when one set of emitters is on versus the other might help you do that.

Another benefit of controlling the odd and even emitters separately on the QTRX sensors is that it reduces the amount that the emitters interfere with adjacent sensors due to the emitted IR light leaking sideways.

- Patrick