Description
An inline Zigbee dimmer (SM315) that replaces the small button cord-switch found on most UK table and floor lamp leads. Adds remote on/off, smooth dimming, schedules, and voice control to any plug-in lamp – without modifying the lamp itself, replacing the bulb, or buying a smart-bulb-only setup.
Native Zigbee 3.0 device. Pairs with Home Assistant (Zigbee2MQTT or ZHA), SmartThings, Hubitat, Philips Hue Bridge, and any other Zigbee 3.0 coordinator. Fully local control – no cloud dependency.
Why this approach beats smart bulbs
Smart bulbs only work when they have power. If someone switches the lamp off at the wall, the smart bulb is unreachable and unrecoverable until someone switches it back on. The SM315 fixes this by sitting on the lamp’s power cord – the bulb stays permanently powered, and the dimmer is what controls it.
- Use cheap dimmable LED bulbs instead of expensive smart bulbs. A pack of 4 dimmable LEDs costs less than one smart bulb.
- Bulb-agnostic. Use any bulb you like – warm white, cool white, vintage filament – as long as it’s dimmable.
- Physical control retained. The button on the SM315 still works as a manual on/off and dim control. Tap once for on/off, hold to dim.
- No “smart bulb stuck off” problem. The dimmer controls power flow; the bulb itself can stay always-on, which means voice commands always work.
Practical uses
- Bedside lamps – “Hey Google, dim the bedside lamp to 20 percent” without changing the lamp itself.
- Floor lamps in living areas – add to a movie-night scene that dims all the lamps at once.
- Wake-up lights – ramp the brightness slowly over 30 minutes to gently wake you in the morning.
- Holiday “presence” simulation – random on/off cycles via Home Assistant automation.
- Reading lamps – dim to comfortable brightness without getting up.
Installation
- Unplug the lamp from the wall.
- Cut the lamp’s power cord at the position where you want the new dimmer (typically where the existing cord switch is).
- Wire the lamp side and plug side into the SM315’s screw terminals (live and neutral – the unit is non-polarised for UK figure-of-8 cable).
- Close the SM315 housing.
- Plug the lamp back in.
- Put your Zigbee hub into pairing mode and hold the SM315’s button for 5 seconds to pair.
Safety: Always work with the lamp unplugged. If you are not confident wiring small mains terminals, use a competent person. The SM315 is rated for use on standard 1.5mm cable (2-core, no earth).
Excellent device! Works as expected.
Easy to install, works like a charm. I wish it had power monitoring though.
Only battery-less mixed Zigbee/manual dimmer that I know of ! Works great.
Item works really well
Build quality and electrical safety is bad. The unit makes a constant whining noise
Having Problems integrating into ZigBee network. Each time I add it, it gets unavailable after a few minutes. But might be an user issue, not product issue.
It works perfectly, I’m not giving 5 stars just because of how it looks. It’s bulky and design and materials are cheap, but it’s the only one of its kind I could find. Would have been nice to have some choice of colour, even just a white option.