That's the way to do it. Too many people think the safe is the security. It is only the delay mechanism. I would also add a pressure pad switch around the safe. There are ways to defeat the motion sensor if the bad guy did recon and knew you used a motion sensor. A pressure pad switch such as slipped under the carpet or under a tile is virtually undetectable. You can use a rasberry pi to also have it send a notification to your phone.

@@DaveSmith-cp5kj They make battery operated devices that go inside the safe. Any vibration, lighting change, temperature change, etc sends a push notification to your phone. Since it’s battery operated there’s no way to defeat it. As soon as they started cutting, the vibration would send the alert. As soon as they cut a hole into it, the light and temperature will change which will send another alert.

@@BW-kv9wj I know what you are talking about, they are exploitable. I'm not going to say how here on the open internet but just realize if you let a guy know it is there and he is up to date, he can get in and out without you knowing. Of course, the chances of you facing that kind of guy is extremely unlikely unless you deal with research or political materials.

@@BW-kv9wj How is the signal sent? If it's WiFi or GSM then it can be jammed rather easily. Does the device have countermeasures for such attacks? Does it transmit to your alarm system (which tend to have countermeasures against jamming) or to a local phone tower, your local router etc? I am sure you have considered these things but I thought I would mention them in case as people are so trusting in security items without realising their are often flaws or simply ways to work around them. Thieves are scum but not all of them are stupid, some are technically proficient and it's important to design everything with those people in mind.

​@@laughingachilles I want to address this and give my opinion. Every system no matter WiFi or GSM based can be jammed, But if the mechanic of the system is written properly this can be resolved. I'm a programmer and we have a term called Crob Jobs - automated tasks on intervals that can be executed. Imagine a very simple device, even a phone with an external battery inside the safe, protected that checks some online URL every minute, with every check the system put one more record in the database, and on the other side if two consecutive minutes missing entries, the system sends a notification. This can be just because the Internet connection is down for a few minutes but can be jammed by criminals trying to bypass the safe. The technique that I describe above is super common for websites uptime monitoring and can be used in safe alarms too - instead to expect If something to happen and After that reactive to send a message, just be prepared that lack of messages every minute is a sign of a problem and do it proactive!

bbtectools.com

Apparently it does considering on the Hatton Gardens job they used one only bigger.

These Bits are designed to cut through heavily reinfored concrete. The video is to demonstrate the ability to cut through both concrete and steel like cheese.