Abstract – Motivated by the need for torque sensing in theÂ Nm range for experiments with insect-sized flapping-wingÂ robots, we present the design, fabrication and testing of aÂ custom single-axis torque sensor. The micorobots in questionÂ are too large for MEMS force/torque sensors used for smallerÂ live insects such as fruit flies, but too small to produceÂ torques within the dynamic range of commercially availableÂ force/torque sensors. Our sensor consists of laser-machined InvarÂ sheets that are assembled into a three dimensional beam. AÂ capacitive displacement sensor is used to measure displacementÂ of a target plate when the beam rotates, and the output voltageÂ is correlated to applied torque. Sensor bandwidth, range, andÂ resolution are designed to match the criteria of the roboticÂ fly experiments while remaining insensitive to off-axis loads.Â We present a final sensor design with a range of 130Nm, aÂ resolution of 4.5nNm, and bandwidth of 1kHz.