ESP8266 questions before buying



  • Hi,

    I'm considering buying a few ESP8266 cards to build sensors and feed my Home Assistant with data via MQTT.
    Anyway, I have a few questions I wasn't able to find answers to here or on the Internet.

    If I buy a NodeMcu Lua development board, as linked on the ESP8266 page on this site (the one sold on eBay by alice1101983), it seems to ship with a USB cable ("USB-TTL included, plug&play"). Do I have everything I need to start, or is this cable just for communication, and I need to power the board externally?

    Speaking of powering the board, from what I read I can power it with 3.3V or 5V, am I correct? The board has a micro-USB board, can I use this port to power the board?
    Once I go "production", I guess I can power it using the 5V+GND ports on the left, or the 3.3V+GND ports on the right?
    Do you know any affordable way to power the board? I would find it unfortunate to buy 5€+ chargers to power a 3€ board.
    What about using batteries? I've read that the board can go in some sort of "sleep" mode. Some of my sensors could easily go to sleep and wake up themselves every 5 to 10 minutes, report what it needs to, and go to sleep again.

    Finally, on the network side, if I'm not mistaken, the board integrates WiFi, so why do you advise buying NRF24L01+ boards? I just want the boards to connect to my WiFi network, not communicate with each other, so I don't need it right?

    I know this isn't a community dedicated to the ESP8266, but seeing some of you are using this board, I hope you might be able to answer my questions :)


  • Mod

    If I buy a NodeMcu Lua development board, as linked on the ESP8266 page on this site (the one sold on eBay by alice1101983), it seems to ship with a USB cable ("USB-TTL included, plug&play"). Do I have everything I need to start, or is this cable just for communication, and I need to power the board externally?

    The nodemcu can be powered through the usb cable

    Speaking of powering the board, from what I read I can power it with 3.3V or 5V, am I correct?

    Yes

    The board has a micro-USB board, can I use this port to power the board?

    Yes

    Once I go "production", I guess I can power it using the 5V+GND ports on the left, or the 3.3V+GND ports on the right?

    I am not aware of a 5V on the left on the original nodemcu but some clones have a 5V and it can be used for power if you don't want to use the micro usb port. 3.3V should be possible, but I have not tried because getting the esp to be low power is too hard (at least for me).

    Do you know any affordable way to power the board? I would find it unfortunate to buy 5€+ chargers to power a 3€ board.

    I use chargers that have gone through european quality tests. Would not dare to use the chinese clones with mains power. The HLK step-downs are popular.

    What about using batteries? I've read that the board can go in some sort of "sleep" mode. Some of my sensors could easily go to sleep and wake up themselves every 5 to 10 minutes, report what it needs to, and go to sleep again.

    This guide https://openhomeautomation.net/esp8266-battery/ has some pointers. I use 3.3V Pro Mini for my battery-powered sensors.

    Finally, on the network side, if I'm not mistaken, the board integrates WiFi, so why do you advise buying NRF24L01+ boards? I just want the boards to connect to my WiFi network, not communicate with each other, so I don't need it right?

    Joining a wifi network and sending data takes 10-100 times more time than sending data using the nrf. That's 10-100 times longer in "power-hungry" mode. That's one of the reasons the nrf is used.

    The Wemos D1 Mini is a nice alternative to NodeMCU. It has the same features, but in a smaller package.


  • Hero Member

    I vote for the Wemos D1 Mini too, if you take the real one from Wemos and not the clones.
    If you buy from Wemos (they have a shop on aliexpress) you are sure to get a good quality board with the last version of ESP8266 (4Mb + better antenna) while the clones and probably all the NodeMCU you find on aliexpress/ebay are made as cheap as possible by various suppliers and you can't be sure of what you really get.

    And for battery powered sensors, arduino + radio is the only viable solution for long battery life.


  • Mod

    But in terms of I/O ports the nodemcu has more than the D1, right?


  • Mod

    @gohan yes and no. More of the "internal" pins are exposed on the nodemcu, but I don't think you can do anything with them. At least not without a lot of tweaking.

    Both packages expose D0-D8, A0 and rx+tx.



  • I also vote for Wemos D1 Mini Pro
    But I have no intention to use those for battery operation, As the other guys states, only option for low power battery operation is Arduino+ NRF24L01+
    Actually a fairly little nice device:
    https://www.wemos.cc/product/d1-mini-pro.html



  • I built all my sensors on NodeMCUs only because I had a large batch of them. My sensors use HLK to step down from AC mains current to 5V into Vin which I've had no problems with so far. Comms is via MQTT to Mosquito running on a Raspberry Pi alongside Home Assistant.

    I'm experimenting now with a 600mAH 3,7V Lipo battery, charger and boost converter with deep-sleep just to see how far I can go.

    Having said that if I would do it all over again I would go the Wemos/NRF way!


  • Mod

    Does it work also with I2C stuff connected to it?


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