Hi.
Android devices are limited with Bluetooth. This is specific to Android since (I believe) version 9. Bluetooth is automatically disconnected by Android after a specific time. Perhaps this has been discussed in this thread. To be honest I didn’t check, it’s bit long.
I don’t know if the Android based gateway that have been discussed above has an earlier android version which doesn’t have this caveat.
My solution has been to buy an old used iPhone for 60CHF. It is permanently powered. The iOS software manages to safeguard the battery so the risk is low. I tried to make an automation to monitor battery level and use a smart plug (Hue) to change only between 80 and 20% but the HA app disconnects and therefore the automation was not launched when necessary. Hence I decided to leave it plugged all the time. I have sometimes (now rarely) disconnects, but most of the time the iphone is connected to bluetooth and it works fine. I may work more on this and find a way to make checks for the app to always be running.
That said, I didn’t yet made the automations and scenes of the Casambi enviornment in Home Assistant. Right now, I occasionally operates from Home Assistant. Lately, everytime I did, it worked fine. The latest releases fo teh component have been more stable. Also I guess Home Assistant evolves
That said, I’m looking forward to Matter. Casambi is a member now. So I expect we will soon be able to implement and use Matter for the Casambi network.
EDIT: Looking at the casambi dev website, it’s clear that a gateway is not the solution for websocket for now.
Is there any other possibility to use the API to control Casambi-powered light appliances without having a phone/tablet gateway just for this purpose?
Currently no, but we are developing new Gateway device that would not require dedicated phone for this purpose.