I’m going to install roller blinds. I have tested a LoraTap module (the orange one on aliexpress) and it works fine, but it is unfit for purpose…
It has an input for a physical switch, that can be used to open and close the blinds. The latest command between Zigbee and the physical switch has priority. Also it is not possible to know the position of the switch via Zigbee. So…
I open the blinds with the switch.
I leave home and ask HA to close the blinds.
A burglar comes, cuts the power for 3 seconds then puts it back on.
The LoraTap module powers up, thinks “yay the switch is in open position so let’s open the blinds”.
I’m looking for a module that doesn’t do that. For example, when powering up, it would do absolutely nothing until someone flips the physical switch.
More likely, a burglar cutting power will leave power cut for his/her agenda.
Yet, a short power loss could produce the same result. With what you have now, I’d want an automation that triggers after a power restoration to check on the status of the blinds and make corrections as necessary. IF, that is, an alternative replacement module is not available (I wouldn’t know).
Someone casing the place and breaking in is only going to go for the easy quick hits, you have to be a higher value target for them to put in the effort for the job.
If you are worried about someone cutting power then invest in a whole home UPS/Battery Backup system that is installed in a secure location in the home or just keep the main networking gear on a dedicated UPS.
Hell I would look into reinforcing your doors and door frames as well as windows before trying to find solutions to the low chance your power will be cut before a break and enter event.
Every switch I own allow for configuration of what to do on power loss and recovery. I’m surprised you have this issue, honestly. Maybe I don’t understand your setup.
For covers I’m using Shelly. I also used to have blebox and it was also working fine, but it broke after a few years.
Shelly connects directly to both the roller engine and to the physical switch and it controls how the physical switch works.
I’m more worried about this scenario: while I’m on vacation, a short loss of power causes all the roller blinds to open, and then a burglar passing by and noticing.
I already have PV, batteries, and critical loads backup. I’m not going to install whole home backup, that doesn’t work.
I’m surprised too! I also have this relay/switch. It does every possible mode. At power-up, it can be configured to use either a fixed value, the previous value, or the state of the physical switch. That’s pretty nice.
So I naively expected this module to also have configurable power-on state. This one is specialized for rolling blinds (ie, it has up/down inputs for the physical switch, interlock, and a timer). And there is no way to set the power-on state in zigbee2mqtt. At power-up, it will roll the blinds in the direction of the physical switch .
What you should be doing is setup a vacation mode for the home automation’s to randomize activity to make it look like people are home and have people you trust check in on the place whilst you are away so that you don’t get squatters infesting the place.
Regardless of security you should have a switch that allows configuration of power return behaviour. It would drive me crazy if my rollers would roll up when there was a small power cut, even if it happens very rarely.
Honestly, think about shelly. I know the alliexpress items are much cheaper, but personally I wouldn’t use the cheapest option for something like that.
Normally I would pick something with a bit more brand in it (lol), the reason I got this SPDT relay module on aliexpress is… I needed a SPDT relay to control two speed ventilation, and SPDT relays seem to be quite difficult to find. The board inside looks alright and it works absolutely fine. Only drawback is the switch input and the relay are not independent. I also got this one which is garbage: click the switch too many times in a row and it disconnects from Zigbee. LOL. So far one good product out of three…
I may end up designing one for the rollers, because I would like position feedback that actually works. Originally I wanted to do that by sticking a magnet on the bottom of the blind and a bunch of door sensors up the rail, but I may as well count the blades with an optical sensor or slap a rotary encoder on the shaft. That’ll be the occasion to use triacs instead of a relay so it doesn’t end up stuck and burn the motor like I saw happen to someone on this forum.