This is a collection of hints, tips and how-to’s related to the excellent little Espressif ESP8266/ESP32 series of WiFi capable boards (and other random and sometimes only tangentially connected electronic and computing subjects).  If you haven’t seen one yet, these tiny boards are only a little bigger than your thumbnail (well, my thumbnail, anyway) and come with a 32-bit microcontroller, memory and the aforementioned WiFi and all at the bargain-basement price of US $3 per pop.  Basically they are cheap enough (and capable enough) to drop into just about any project which you want to connect to the ‘net.

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  1. Hello, a question: when I sept in tasmota: Generic module to create node mcu with 4 relays they work according to each other. When I turn on one of them, the other goes off. For example: if I turn on the relay 1 while the number 3 is on, the latter goes out as soon as the relay 1 goes ON.
    Is there any command to give in the console? Thank you for your respone!!!


    • Nicolò,

      Sounds like you have a bad PSU. The TASMOTA console will give you “toggle” control over each individual relay and they normally should not affect each other. What you describe sounds like one relay stealing current from another when it switches on, which would normally only happen if you’re using an under-powered PSU.

      The generic relays on the modules from China are 5v working with a 68~70 Ohm coil, which will give you somewhere in the region of 75mA per relay (in addition, some of the modules have a very silly opto-isolator …which doesn’t isolate anything, but still draws an extra 10~20ma per relay)..

      Don’t try to run the relay modules from the ESP8266 3v3 supply; doing that will reduce the relay current down to about 48~50ma, which probably isn’t enough current (and in addition, will cause spikes on your ESP +ve rail).

      Let us know how it goes,



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