The basic model without readers is supplemented with a standalone hardware and software ability to count passages and monitor the number of people indoors. The turnstile will automatically block the entrance when the number of people indoors reaches the set limit. Implemented 2 schemes of work:Single turnstile T3-NO-SF (BF) v.1.2 & T2-M-SF v.1.2;Master turnstile T3-NO-SF (BF) v.1.2 & T2-M-SF v.1.2 and synchronous connection of up to 3 additional turnstiles T3-NO-SF (BF) v.1 & T2-M-SF v.1 for collaboration.The counter module is used to record quantitative data and synchronize turnstiles. The Android application MaterCard is used for configuration. The Android application Visitor Counter is used for monitoring STOP-COVID solution.