The Wemos D1 mini needs to be programmed for the device to function as an infrared transmitter and receiver. This can be done using the esptool program.
  1. Download the appropriate esptool binary for the platform that is going to be used to flash the Wemos D1 mini, and unpack the archive.
  2. Download the espirp firmware and unzip it in the same directory as the esptool.
  3. Connect the Wemos D1 mini to the computer using a microUSB cable.
  4. Open a terminal and navigate to the directory where the files from step 1 and 2 have been unpacked.
  5. Run the following command (adjust the -cp option if your Wemos D1 mini appears as a different serial device):
    ./esptool -cp /dev/ttyUSB0 -cd nodemcu -cb 921600 -cf espirp-fw.bin -ca 0x300000 -cf espirp-fs.bin
    esptool -cp COM5 -cd nodemcu -cb 921600 -cf espirp-fw.bin -ca 0x300000 -cf espirp-fs.bin

Initial setup

A newly programmed device will not have any credentials for a WiFi network to connect to. In this situation, or when it is powered up and doesn't find the configured WiFi network, it starts a WiFi access point. The SSID for this network will be 'IR transceiver ######', where ###### is a 6 digit hexadecimal number. Use a mobile phone, tablet, or laptop to connect to this WiFi network.

The device provides a captive portal, which will normally automatically direct you to the configuration page. If that doesn't happen, point your browser to to go to the configuration screen.