Power meters for bikes

Power meters for bikes

Cyclists of all levels are committed to self-improvement and pushing their limits. They go for precision in training, efficiency and avoidance of overtraining and injury. 

Power meters serve as an invaluable ally for cyclists, offering a level of insight that can’t be easily replicated by other metrics. E-bikes will also profit from force sensors as the ride experience will be improved.

Power is calculated based on the force measurement which itself in turn is best done by means of strain gauge sensors mounted on the crank arms, the axle or the chain ring. A major challenge thereby is that the sensors and sensing electronics are mounted on rotating parts. The means the sensors need to be operated by small batteries or by energy harvesting and the data transfer has to be wireless. The outcome is that the converter has to be precise enough to give sufficient resolution for the small signal span from the strain gauges, and on the other hand the converters need to work with ultra-low power consumption. 

ScioSense PS09 resistance-to-digital converter solves both challenges. It can provide 100k scale divisions and at the same time consume only microamps. Up to four half bridge sensors can be connected to the PS09.

Application diagram power meter

Figure 1: Power meter


PS09 Resistance-to-Digital Converter

Design requirements / challenges

Design requirements / Challenges:

  • Precise resistance measurement
  • Multiple strain sensors to be connected
  • Ultra-low power consumption for contactless operation