Comments on: ESP-NOW Two-Way Communication Between ESP8266 NodeMCU Boards

By: Sara Santos

Sara Santos — Wed, 30 Jul 2025 15:54:33 +0000

In reply to WeekendEngineer. My code is compiling just fine. Are you using ESP8266 boards? Which version fo you have installed?

By: Sara Santos

Sara Santos — Wed, 30 Jul 2025 15:50:25 +0000

In reply to WeekendEngineer.

Thanks for letting me know.
I’ll double-check the codes.
Regards,
Sara

By: WeekendEngineer

WeekendEngineer — Mon, 28 Jul 2025 13:47:01 +0000

Espressif board Version 3.3 has altered the API, in relation to this code the arrangements for creating the callback functions has changed.

I seem to have found that:

// Callback function
void OnDataRecv(const esp_now_recv_info * mac, const uint8_t *incomingData, int len)

and for the transmitter

// Sent data callback function
void OnDataSent(const wifi_tx_info_t *mac, esp_now_send_status_t status)

By: Dhairy Bagave

Dhairy Bagave — Sat, 29 Jun 2024 05:42:31 +0000

How can I facilitate two way communication between esp8266 and my phone
I prefer doing it by keeping the wifi of my mobile on.

By: Malcolm McGrath

Malcolm McGrath — Tue, 04 Jun 2024 02:47:29 +0000

Thanks very much for your project.

I implemented your code with two D1 minis, works a treat, used a couple of switches and leds rather than using and humidity. My plan is to add a Gravity voice recognition module to the sending device and create an Alexa type device for controlling an alarm system.

So far so good. 🙂

By: David

David — Tue, 11 Apr 2023 13:25:39 +0000

In reply to Sara Santos. I was able to get this to work. I did not realize to just remove the FF portion and enter each section of the MAC.

By: David

David — Tue, 11 Apr 2023 13:24:22 +0000

Hello. I find this feature very usefull and I was able to replicate it with no issues. I am trying to implement this into an existing sketch that I have with a Wemos D1 mini. It is already setup using OTA updates and NTP for network time. It also has a working OLED display and temp sensor. When trying to integrate this, It is not working. I took your existing code and tried to just add the OTA code. It seems the line WiFi.mode(WIFI_STA); WiFi.begin(ssid, password); for the OTA code conflicts with the line WiFi.mode(WIFI_STA); WiFi.disconnect(); in the ESP_Now code. Can these two useful features( OTA Updates and ESP_Now) exist together in one sketch? Thank you

By: Sara Santos

Sara Santos — Sat, 01 Apr 2023 14:51:07 +0000

In reply to David.

Hi.
What’s the issue?
It seems to be in the right format.
Regards,

Sara

By: David

David — Sat, 01 Apr 2023 10:48:07 +0000

Good day. I found this article and it seems to be just what I am looking for. I have two aquariums each with a Wemos D1 mini and temp probe with OLED display. Both are connected to WiFi to get NTP for running timers. I want to send temp data from one to the other so that one can display two temps. I am running into the issue of inputting my MAC address in the line
uint8_t broadcastAddress[] = {0x2C, 0x3A, 0xE8, 0x0E, 0xBB, 0xED};
what format is this looking for and how do I convert it? Thank you

By: Sara Santos

Sara Santos — Tue, 10 Jan 2023 17:08:11 +0000

In reply to Prof.K.R.Rao.

Hi.
It is very difficult to troubleshoot this issue without further info.
The first step is to check that a ESP-NOW sketch works with both boards—check that both boards are able to receive and send ESP-NOW packets.
Check the MAC address.
Check the board model you’re using. It is better to use the specific GPIO that connects to the built-in LED instead of LED_BUILTIN (because the board you select might not be exactly the one you’re using).
Check if you get any errors on the Serial Monitor.
Regards,
Sara