The transmitter module is based on NE555 infrared transmitter module.38KHz carrier circuit board produced by the NE555,no MCU"s PWM pins to reduce the corresponding code,reducing the burden on the MCU.SIG module pin is high,the module will send an infrared signal of 38KHz,SIG pin is low,the module will stop sending infrared signals.The infrared receiver module based on integrated infrared receiver head.The infrared receiver module and transmitter module can complete the infrared remote control with the codec program.It can receive the modulated infrared signal of 38KHz that is sent by the IR transmitter module and demodulate it into logic level,ie,when it gets the modulated infrared signal,it outputs one negative pulse and returns to normalcy (High level).The infrared receiver module and transmitter module can complete the infrared remote control with the codec program. Infrared Emitter module: Operating voltage:4.5 - 5.5VDC Operating Current:50mA (max) Emission angle:45 degrees SIG pin current:High lelel 0.4mA (max),low level 1.4mA (max) You can manually adjust the direction of the launch tube according to the actual application requirements Infrared Receiver module: Operating voltage:3.0 - 5.5VDC Operating Current:2mA (max) Receiving angle:90 degrees Size:2.4x2.4cm/0.94x0.94inch Note: Please allow 1-3mm error due to manual measurement.pls make sure you do not mind before you bid. Due to the difference between different monitors,the picture may not reflect the actual color of the item.Thank you Package Includes: 1x Infrared Emitter module 1x Infrared Receiver module