The Amazon Dash Button was a small device intended to be used for easily reordering a single product from Amazon. It was just a small plastic enclosure with a single button, and could be registered to order a particular product at the press of a button. In order for it to work, it had to connect to the internet via WiFi. The hacking community quickly found out that it could be repurposed for any kind of IoT task, and Pierre-yves Baloche has a guide on how to use one to soft shutdown your Raspberry Pi.
The Raspberry Pi doesn’t have a power button of it’s own, and it automatically turns on whenever it has power. To turn it off, many people simply disconnect the power. But that can actually cause corruption on the SD card, which is why you should first perform a soft shutdown before unplugging the power. You can do that from the command line or desktop GUI, but that’s difficult to do when you’re using the Raspberry Pi in headless mode. With the Amazon Dash Button, all you have to do is push the button and your Raspberry Pi will safely shut down.
To do this, all you’ll need is the Amazon Dash Button. Those were recently discontinued, because Amazon expects you to just use your Echo to order products, but they’re still easy to find secondhand. Once you have it, you can connect it to your Amazon account, but don’t actually register it to a specific product. Then install the Python Amazon Dash software and follow Baloche’s instructions to set it up. The final step is to block the Dash Button’s access to the internet through your WiFi router, which will keep Amazon from sending you notifications reminding you to register it with a product.