This morning the brand new Sonoff Mini PM arrived on my desk. The PM stands for power monitoring and this is a truly TINY PM (power monitor) (not switch), comparing well in that respect with other manufacturers I’ve come across.
Which is why I wonder, with such a marvellously small small, easily able to fit into virtually any standard wall switch, they didn’t find a way to make it neutral-free and power switching – but then I guess you have to add a relay to get that. Maybe power monitoring isn’t even possible without a full set of live and neutral connections?
To recap, my all time favourite actual miniature switch is the Sonoff ZBMini L2 which isn’t power monitoring but which IS a switch. It has 4 connections, i.e. live in, live out and S1+S2 – this neat device fits into standard wall switches which at least in homes I’ve owned in the UK and Spain have NO NEUTRAL. They simply have 2 wires, one from LIVE and the other to the lamp or lamps being controlled. In use, you disconnect the two wires on the original switch and put those into the S1 and S1 connectors on the ZBMini. The original wires in the wall go to Live in and live out. Hence now you have a wall switch which works locally even if the WiFi goes off.
For size only, original Sonoff Mini switch versus Sonoff ZBMini L2 switch versus the new Mini-ZB1GP power monitor below…
Original roughly 40*42*20mm, ZBMini L2 39*31*18mm. The latest device 31*28*16mm. See Sonoff’s site before trusting these measurements… but this new device – which still claims to monitor 16a max going through it – is amazingly small but remember it is not a switch.
However, rather handy for augmenting standard wall sockets which adding smart Zigbee power monitoring.. but it would really be essential to label the sockets to say “NO heavy duty devices” – a typical household condenser-dryer on 230v could get dangerously close to the 16A limits of this device. Mostly everything else in my home (we don’t have an electric oven but we do have an air fryer and microwave oven, both of which fit into the monitoring range of this device.
See Sonoff info in the photo here..
Enough blether – I just happen to have an obscenely thick power lead handy I can plug into the L and N connections to set up the device. I’m going to try to set up this new Zigbee wonder without the Sonoff app and straight into Home Assistant via my Zigbee2MQTT add-in (and my SMLIGHT Zigbee coordinator – I could have used the new Sonoff Bridge MAX Zigbee hub but I’m happy with my existing setup)..
Ok plugged in and the blue light is flashing…. I’ve connected the blue and brown wires correctly but note that in Spain, most plugs can be connected either way around and also they use blue and black (black means cold to me but there you are – I just happen to have loads of UK cable).
What next…. Zigbee2MQTT – allow join… “Zigbee smart power monitoring sensor added” – done – and here’s a list of entities – note – no switch.
I noted an update available once in HA – note that Zigbee updates can take a long time – this one seemed to fail part way through so it could be back to the Sonoff app for updates.