We are surrounded by increasingly complex networks of smart objects, yet our understanding and attachment to them is rather limited. One way to support stronger end users’ engagement with such complex technologies is by involving them in the design process and, with the advent of Arduino prototyping platform, even in their making. While DIY practice offers the potential for stronger user engagement with physical artifacts, we know little about end users’ DIY practice of making complex electronic technologies and their potential to ensure engagement with such devices. In this article, we report on interviews with 18 participants from two green communities who built and used an open source DIY energy monitor, with the aim to explore the end users DIY practices of making such complex electronic devices. Findings indicate four key qualities of DIY monitors: transparent modularity, open-endedness, heirloom, and disruptiveness, and how they contribute to more meaningful engagement with the DIY monitors, elevating them from the status of unremarkable objects to that of <i>things</i>. We conclude with three implications for design for supporting end user development of complex electronic DIY: designing transparent open hardware technologies, standardizing communication protocols for the current and future DIY of IoT, and deliberately calling for personal investment and labor in the assembling of DIY kits.