It seems that this device can be operated for infrared detection. Make the transmitting circuit independent and put a variable resistor to facilitate changing the frequency until it matches the resonance of the receiving unit. It seems that it is possible to balance the coils on a single ferrite in some way while reducing the transmission power of the coil. I'm not sure, unfortunately I didn't make the device. I try to simplify it for amateurs and get rid of unnecessary accessories that will pose a problem for some.