47 - but this is cheating, as it includes 30+ Raspberry Pi's used for my business to monitor and control 3D printers, and climate control in my workshop. Apart from them, 4 PCs, a couple of laptops, phones, tablet, Sky box, one smart TV. How do you manage the potential for one of the many devices on the network to be insecure or even malicious? I'd be interested to read just about that! I've actually got a lot fewer installed IoT devices than I'd like because I've not yet set up the parallel untrusted network I planned, which awaits three Amazon Echo Dots and several Sonoff switch relays, because I don't want them sharing a network with my customers' I.P.