I’m looking for a small (button) battery operated device with just has a single pin hole LED light. Connected over wifi or zigbee is fine.
I want it to go on my front door under keypad to indicate if the door is unlocked or locked. Using August auto-unlock and it doesn’t always work so would like a visual indicator which I can set via a Hass.io Automation.
Anything like this exists before I go custom, maybe hack a Xiaomi button switch is an option.
Well I was going to suggest an ESPhome solution but even if you get a high efficiency LED that can give you a reasonable brightness @1mA, you’ll still be replacing batteries 3 tines a year if the LED is constantly on.
thanks, yeah I don’t mind changing batteries, could bump to AAA, I have to replace the August keypad/lock roughly the same. I’m thinking even flashing every 5 seconds or so would greatly increase time.
That’s why I’m thinking zigbee, the Xiaomi battery devices I have, have only dropped 1 or 2 % of battery life in a year now, they are amazingly efficient (though no always on LED)
Found this custom setup, which looks like a zigbee based US light.
My calculations were with a 2200mAh Li 18650 cell. It would take 3 x AA in series to get a similar result.
That is powered from a mains plugpack.
In the comments it’s converted to battery powered.
Looks like a lot more investigation is needed, I’m sure these button as efficient at sending status only https://www.youtube.com/watch?v=zJAjfH7Ycfc
A bit late to the party, but I was looking for the same thing.
I am considering using an Aqara mini button or a temperature/humidity sensor.
They are battery powered, very small, come in a nice case, and are pretty cheap.
These devices are designed around the JN5169 by NXP and are re-programmable, so you can write custom firmware for them.
You can see a teardown here (you might need to use google translate if you don’t speak french)
Someone already wrote custom firmware for the mini button (chinese, but google translate to the rescue):
there’s an interesting example there of how to send zigbee broadcast packets so you can make the button work with a receiver directly without requiring a hub/gateway
With this, you can create custom zigbee battery powered LED indicators, sensors or buttons/controllers easily, and have them packed in a nice small good looking enclosure.
I hope to find the time soon to have a go at this myself. If I do, I’ll post the results here.
One more link I’d like to add
And a nice getting started guide for JN5169 development:
For those willing to get their hands dirty (or those that can get started on it faster than me 
)
Not sure if this is a possible solution, but there appears to be a bluetooth flavor of what you’re looking for, at rfmobistore - look for Bluetooth Beacon. Appears to run up to a year on a coin battery, and contains both a buzzer and an LED. I ordered one and received UUID information from the seller, but haven’t had a chance to see if I can get it working with something like nRF Connect or HA. I’ll post a follow-up, if I get it working.
Thanks! this is interesting indeed it will be BlueTooth LE (low energy) … going to have a look at it deeper but how would I add Bluetooth to my Hass server? Never thought about it.
I’m also looking for a battery powered status light if anybody has had any other ideas along the way.
What did you end up with? I want to have a little red indicator when the dishwasher is running 
I’m also interested in this. Any solution?
Bumping this up, maybe somebody came up with an idea?
As per Silthion - bumping up in case anyone has found an answer to this yet?
Thanks!
Add me to the list of interested persons…
Also interested in this
Very much interested…
I use an Apollo MSR-2. It gives me other readings but it has an LED on it that you can turn on and off. I use it to see if someone is in the jack and jill bathroom.