How to Turn a Light on and Off Using a Bluetooth Sensor

I'm always thinking something I want to build. You can buy little cheap battery power, proximity, Bluetooth low energy devices that can just hook on your keychain. The best part for me is I just take the train up to Shenzhen. I go straight to the manufacturer for even way cheaper. So then you're like, well, I don't need to build a new one, although I still want to,. But it probably is good as someone that I bought, right? Like, I have so much stuff like that right now. It's kind of like, it's like similar to your situation with the controller, right? You figure out how to make it work again.