Learn how easy it is to create your own monitoring system! Hobbyist components and a rich 'maker' community puts advanced system designs well within the reach of your average software wonk. Stop planning and start building! Our case study is 'GroMon', a solution for monitoring a tiny indoor lettuce garden. Our wireless sensor keeps track of temperature and humidity, if the plants get too hot or too cold then we are notified via text message. We will discuss the design goals and architecture, as well as component selection, prototyping and debugging steps. With a little bit of programming skill and patience, anyone can build this network. Learn how to easily extend this solution for your own use. Our stack is Node.js running on a Raspberry Pi. We connect over Bluetooth to an Arduino hosting a single sensor. All components can be purchased off-the-shelf, no soldering is required and the total cost is around $80. Code and bill of materials is available on GitHub, let's hack!