HM-10 not found over time

Hello everyone,

I have an application which involves connecting from the iPhone to a PCB (running Arduino Mini Pro), using HM-10 BLE. Got a few of these BLEs from AliExpress for like $6. The BLE is already paired, as the App already knows its name and connects straight away. Overall, they work great, but:

I do have a problem, which appears randomly, from time to time. The PCB is powered almost 24/7, the BLE receives connections every now and then. Just sometimes, it happens I cannot find/connect to the BLE. There are currently 3 PCBs running, all of them having this issue. It's frustrating because it can work for 1 month, or 1 day. Out of the blue, sometimes, I just cannot connect or find the BLE. I've also tried another BLE application (iOS) called LightBlue and indeed the BLE is not there. My solution is to disconnect/reconnect the power - but I really want to avoid this.

Another solution I tried is putting the BLE to sleep after 10 seconds it was disconnected. It worked for a few weeks, then the problem appeared again. I've also searched the web but came up empty.

My guess is, the constant power supply may somehow affect the BLE and shut it down ?
Has anyone encountered anything similar ? BLE somehow "freezing" and it's not discoverable/connectable anymore ?

Really appreciate any opinion, thank you!

I've recently noticed that the problem appears and goes by itself.

• Tried to connect - nothing, the BLE was undiscoverable (even if the LED was blinking)
• Waited 1-2 hours
• Tried to connect - worked

This is really weird