A Pmod for emitting and receiving baseband IR signals. It can be used to decode and emulate IR remote controls, IR communication or other IR-based sensors.
This module contains simple analog signal conditioning circuitry to connect a LED and a photodiode to FPGAs or microcontrollers. The interface is a 12-pin Pmod (Spec B) with the following pinout:
- P1: TX, input, active high, controls the IR LED via a simple MOSFET.
- P2: GND
- P3: RX, output, is pulled high if the photodiode receives a stronger-than-average IR light.
- P4: GND
- P5, P11: GND (Pmod power supply pins)
- P6, P12: 3.3V (Pmod power supply pins)
- P7-P10: Not connected
The receiver contains a transimpedance amplifier, a high-pass filter and comparator to produce a clean digital signal. The high-pass rejects ambient light along with signals slower than about 10 kHz, the usable bandwidth is about 100 kHz. The receiver circuit was inspired by IRis.
If you have a PYNQ-enabled FPGA-board, load PYNQ_IR_Communication.ipynb onto it to explore an example of sending and receiving IR signals. This notebook works with the BaseOverlay and is completely self-contained not needing any additional drivers. It expects an IRTransceiver connected to PMODA.