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MEMP
Measure of the power developed by a cyclist
The purpose of this project was to create a power measurement prototype at the pedal. The average power is determined by the formula:
A force sensor placed between the pedal and the foot of the rider, measure Ft. It is composed of two pairs of flexible blades that ensure the decoupling of the force in two components Fpp and Ftp.
The strain gauges placed on the blades characterize the applied force. When the flexible blade is deformed by the force applied, the resistances of the strain gauges vary. The microcontroller measures the changes of these resistors connected in bridge and deduces the applied force.
The rate of the pedals is measured by a magnetic barrier. A microcontroller calculates the instantaneous power and the average in one revolution of the pedals. It then sends this data by RS232 communication to a computer. An interface allows the user to analyse the power generated by the cyclist.
Technical skills
The purpose of this project was to create a power measurement prototype at the pedal. The average power is determined by the formula:
Pm = Ft * Rp * fp
Relative to the pedal, Ft is the tangential force compare to its movement, Rp its radius and fp its rotational frequency.
A force sensor placed between the pedal and the foot of the rider, measure Ft. It is composed of two pairs of flexible blades that ensure the decoupling of the force in two components Fpp and Ftp.
The strain gauges placed on the blades characterize the applied force. When the flexible blade is deformed by the force applied, the resistances of the strain gauges vary. The microcontroller measures the changes of these resistors connected in bridge and deduces the applied force.
The rate of the pedals is measured by a magnetic barrier. A microcontroller calculates the instantaneous power and the average in one revolution of the pedals. It then sends this data by RS232 communication to a computer. An interface allows the user to analyse the power generated by the cyclist.
- Mechanical design and machining parts
- Electronic circuit design and realization of the prototype
- Microcontroller programming in assembler
- Programming interface in Visual C++
© 2020 Amadou Miéville