This experience report describes two iterations of a curriculum development process in which middle school teachers worked with our research team to collaboratively design and enact instructional units where students used sensors to investigate scientific phenomena. In this report, we examine the affordances of using a sensor platform to support the integration of disciplinary learning and computational thinking (CT) aligned with Next Generation Science Standards and the CT in STEM Taxonomy developed by Weintrop and colleagues. In the first unit, students investigated the conditions for mold growth within their school using a custom sensor system. After analyzing implementation experiences and student interest data, our team engaged in another round of co-design to develop a second instructional unit. This unit uses a different sensor system (the micro:bit) which supports additional CT in STEM practices due to its block-based programming interface and its real time data display. For the second unit we selected a different phenomenon: understanding and designing maglev trains.