Access control / Log for Coffee Grinders, using RFID cards (13.56MHz)

From “Blynk” app you can set:

  • ON time for the grinder (0.1 sec = 1 unit in app)
  • Lock / Unlock the issued RFID cards (realtime) -> Select a User -> Push “Lock/Unlock” button
  • Turn ON the grinder for “Guest” in app → Push “Grind Now for Guest” button
  • Replace a “Lost Card”  -> Select a User ->  Push “Lost Card” button -> approach a New Card to the RFID module
  • Reset the counters to “0”, for all Users → Push “Reset” button

Hardware Components:

  • Wemos D1 Mini or NodeMCU (ESP8266)
  • RFID module – MFRC522
  • RFID cards/tags (13.56MHz)
  • SSR to control the Grinder


  • install “Blynk” app from Play Store / App Store.
  • Create a “Blynk” account
  • Scan the provided QR code for this project (you need to buy some “Energy” points)
  • Check the Blynk1,2,3 pictures for the next steps
  • Copy the provided Libraries to Arduino > Libraries directory
  • Replace the “xxxxxxx” in the code, with your “blynk_token” received from Blynk
  • After programming the WiFi module, connect to the “CoffeLOG” network Access Point, started by the WiFi module
  • Type this IP address in your web browser, to access the device Config Portal:
  • Configure WiFi > Select your WiFi network > Insert the Password  > Save.
  • Now, after AutoRestart, the module should be visible in the Blynk app.

Note: while the grinder is ON, the communication with Blynk app is interrupted.

You can download the Sourcecode and Schematic from Github.

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