I built this device to allow two ESP8266 uC to communicate and listen to ESPNow messages coming from my sensors to ESP-01 to be pushed to the second ESP-12F and have them sent over Wifi/MQTT. Both ESP-01 and ESP-12F will come pre-loaded with the latest firmware. Please note, you will most likely need to change the source code to make them fit your need (if you are using a different ESPNow message structure than mine).
On initial boot, wait 30 seconds, the hub broadcast will an SSID called ‘Setup Portal‘ with password ‘mrdiy.ca‘. After connecting to this SSID, go to http://192.168.4.1 and follow the instructions.
To program the ESP-12F
You will need a FT232R USB to serial programmer (3.3V only). The pins align with the PCB, simply plug them in on the left hand side and upload – as shown below. No need to put the ESP in programming mode, the FT232R takes care of that. Please note, you will not be able to flash the ESP-12F when the ESP-01 is connected to the PCB. Make sure it is unplugged before flashing.
Another option is to use Over-The-Air flashing which comes with the original firmware.
To program the ESP-01
Unplug it and use your usual way to program any ESP-01 module. I usually use this adapter.
Download the BIN file for the Gateway/ESP-12F ( 4MB FS:none OTA:~1019KB).
Download the BIN file for the Receiver/ESP01 (1MB FS: none OTA:~502KB).
You can download the source code for my entire ULP sensors system ( this includes the source code for the receiver/ESP-01 and the gateway/ESP-12).