You can certainly buy a ready-made drink mixing robot if you're flush with cash, but wouldn't you rather spend that money on the drinks themselves? Yu Jiang Tham thinks so -- he recently designed Bar Mixvah, a robotic bartender you can build yourself with $180 in parts. The key ingredient is an Arduino Nano microcontroller that takes your requests through a web-based interface. After that, it's mostly a matter of 3D printing the frame and wiring up the pumps that will make your beverage a reality.