I’ve had this for a while – didn’t do anything when I pressed it’s tiny side button – then I looked at the instructions and it needs the little Meross HUB to work… so I put it to one side for a matter of months – then last week contacted Meross who sent me the HUB.I plugged in the Meross HUB and paired it with their APP – EASY… then came back to the MS100F but could not get any light to come on (tiny hole in the top edge of the MS100F – photo on the left) when pressing it’s side button (hole in the opposite side) … SO I opened it up – inside, a large CR2477 battery.The sensor has a solar panel as you can see and so only uses the battery in the dark – assuming you put it in the sun.
Because I have a voltmeter – I decided to take a look at the sensor board – no LED – how did THAT happen? And no sign of the LED floating around inside the box.I checked the battery and it was fine despite months in a dark cupboard.So next I held my meter against the (thankfully marked) LED PCB traces while pressing the side button – I noticed a flicker on the meter – so it IS all working – just no LED.
I put the HUB into pairing mode and pressed the button on the sensor briefly – NEW DEVICE FOUND in the Meross APP.Great.Note that the Meross site refers to working with Apple Home – well, I don’t use Apple-anything – we have standard Android phones here at Bedrock.
No problems there.Anyway, now this was up and running, I checked the sensor in the APP – great – with it sitting outside and the HUB in my office, I’m seeing updates every few minutes.I’m itching to see if the sensor hits it’s limit (50c?) sitting baking in the hot Spanish summer sunshine.
Up to now, It hasn’t gone past 34c so all is well.It has been out there for half an hour in the sun and everything seems to be fine.Oooh, 36.1c and counting…..
11am – 41.8c and counting… huumidity down to 23.2% and it’s only mid-morning.NEXT: Having gotten the device working (easily) in the Meross APP, I thought I’d take a look in Home Assistant to see if anything had magically appeared.I noted a request to accept the Meross Hub – I did that and next thing I knew – an MS100 sensor appeared like magic – battery – humidity – temperature entities.
I won;t go into all that as Home Assistant integration devices have been covered ad-nausium here and elsewhere but I’m going to add them to my normal temperature sensor tiles in HA, I hate having to go back and forth between APPs.According to HA, the battery is at 100%, so it looks like having the sensor lying in a drawer for months didn’t do any harm after all.I asked Meross a load of questions – here are their responses: “To pair the MS100F, Please short-press the button in the hub twice, then its LED will flash green.
Please place the MS100F next to the hub and use a pin to insert its hole and press it once, then its LED will flash.Please wait for a while, then the MS100F will be automatically added to the hub.After setup process completes, the LED of the MS100F will not light up any more.” “The MS100F collects temperature and humidity data every 3 seconds.
When the measured change exceeds the set thresholds — ±0.3C for temperature or ±5% for humidity — the device will immediately report the data to the hub. Additionally, if no data meets the reporting threshold for 10 minutes, the MS100F will also send an update to the hub. The hub then forwards the data to our server, which is subsequently updated in the app interface for your reference.” “The MS100F communicates with the hub using a 433MHz radio frequency.As a result, its data transmission can be affected by several factors, including:-The distance between the device and the hub-Obstacles such as walls or furniture-Interference from other wireless devices operating nearby” “Due to variations in room layout, wall materials, and home environments, we’re unable to provide an exact communication range.We recommend placing the hub and sensor close to each other and avoiding thick walls or heavy interference where possible to ensure stable communication.” Meanwhile I was looking at Home Assistant… there it is… note the temperature and humidity ADJUSTMENT option on the photo, left.
Nice.And here it is in Home Asssistant, rapidly approaching the maximum stated temperature for the device..I wonder what will happen…The hub is on my bench – then 3 metres to the breezeblock wall, then 4 metres to the table outside in the sun with the sensor sitting on it.
