Amazon has themselves posted easy to follow instructions, on their GitHub page, for how to create your own Alexa-enabled speaker, similar to the Amazon Tap, using a Raspberry Pi 2 and other off-the-shelf parts. The project is very similar to “The $10 Echo” by Sam Machin, creator of the Alexa Web App. Due to limitations of Alexa’s voice services, the project doesn’t have always listening capabilities, like you have on the Amazon Echo or Echo Dot. Instead, you have to press a button to before speaking, just like the Amazon Tap. If you already have most of the components, this could be a fun project to put together.