Last weekend, I got to thinking about fire safety and Home Assistant. I’m always anxious about not leaving the iron on, and even though my iron has an automatic shut-off, I’m never fully comfortable with a solution that wouldn’t be endorsed by Tim “The Tool Man” Taylor. For optimal safety, only a Smart Iron® will suffice. The only problem: smart irons don’t exist, perhaps because that’s an insane idea.
To tackle this, I used a YoLink Smart Energy Plug I had lying around, which monitors energy usage and pushes it back to Home Assistant via the YoLink integration. I have a bunch of other YoLink sensors, so this was the path of least resistance, but you could use any smart plug that pushes consumption data.
Out of the box, this gets me to a good starting point – a sensor that shows live power consumption from the outlet I plug the iron into:
Monitoring on/off status of an iron is trickier than just straight power consumption, though, because the heating element doesn’t continually draw power. Instead, it alternates on and off, drawing a lot of power when it’s on and no power when it’s off.
To work around this, I created two helpers:
- An “Iron Max 5m Draw” statistics sensor, with a max age of 5m, exposing the maximum power draw in watts over the last five minutes.
- A simple “Smart Iron” binary template sensor, with this template:
{% set usage = states(‘sensor.master_bedroom_iron_plug_iron_max_5m’) | float(0) %}
{{ usage > 50 }}
I now have a “Smart Iron” device in Home Assistant, which shows “On” if a device connected to the outlet for the iron has drawn more than 50 watts in the last 5 minutes.
From there, I created two simple automations:
- If the iron has been on for more than an hour, shut the outlet off and notify me
- If I leave the house and the iron is on, shut the outlet off and notify me
Now I can sleep easier knowing I have this additional and probably unnecessary safety check!
The next frontier: the stove
The stove has proven to be a more formidable adversary.
This is a solved problem, and the right answer is an energy monitor like the Rainforest Eagle (which tracks whole-home energy usage) or Shelly clamp sensors (which wire directly into the circuit).
With that said, I had to try a cheap solution, which was a YoLink Temp & Humidity Sensor near the stove and a helper entity that tracks the delta between that sensor and another temperature sensor nearby in the kitchen.
This proved to be ineffective – the delta at times can be quite substantial even with the stove off (since the stove sensor is enclosed but the other is near a window), and short of mounting it directly above the stove, I haven’t found a position for the stove sensor that creates a significant enough delta to solve for that problem.