HPV Performance App

HPV Performance App is a bicycle/tricycle/quadricycle Human Powered Vehicle Android application ("app") in development at Replikon Research for sale in the Play Store.

There are no releases to date. We may release a general purpose windowing / smoothing app.

A first edition will instruct data collection and processing using existing apps and desktop software including image processing software for frontal area measurement, coefficient of drag, rolling resistance, rider and e-hub combined power input on level "cruise" and on hill attack, and hysterysis and eddy current drag of e-hub(s) if so fitted by collecting and smoothing GPS, barometer, hygrometer, thermometer, accelerometer, and possibly other sensor data with smartphone and PC.

The first version of the first edition will require the Physics Toolbox app and Microsoft Excel spreadheet software, and will use rolling averages to smooth the data collected. Kalman windowing and "information matrix" methods will be used later.

A second edition will process data collected with existing apps on the smartphone to provide CdA, A, Cd, r, etc. on a file-input screen-output basis. This edition *may* include a pay-per-use processing service here at replikon.net; not a CGI script, but local labor by the developers to broaden the subscriber base. This will be easier to use than the first edition.

A third edition will process data during rides using audio cues indicating GPS fix and buffer fill conditions for ride start, will process during the ride, display at end of ride, and log each ride to a shareable ride log with notes of vehicle condition so that, e.g. tire pressure and gear selection may be compared during, e.g., multiple laps, or separate trips over the duration of ownership, or between owners of similar vehicles, or amongst HPV enthusiasts. This will be the easiest edition to use. The third and later editions will offer time lapse photography and video during data collection and by then, our Etsy store will offer the modified bright yellow carry hat mentioned below. We may or may not offer Note 3 phones preloaded with our Managed Apps list.

A fourth edition will offer sensor/survey fusion: the most relevant sensors are GPS, barometer, the accelerometers and gyro, hygrometer, compass, and thermometer; the most relevant suveys are topography, benchmark locations, nearby airport barometers, and declination.

A fifth edition requiring root privilege will be available as a digital download on the company Etsy store, "TheReplikonSchool", and will include the ability to disable selected sensors. This edition will only be slightly more complex and involved than the fourth edition but will introduce some features that are available only on a rooted smartphone.

The image processing segment, on PC, or smartphone, will input a known scale image and output the frontal cross section with square centimeter resolution. Cross sections from various angles *may*be included, because little research has been done on the nonlinear, nontrigonometric effect of crosswind / relative wind during a ride.

The equation not including composition of air, for density, used in drag calculation is, courtesy Wikipedia:

Density of humid air in kg/m^3 as a function of p.d, the partial pressure of dry air in Pascals, and p.v, the partial pressure of water vapor in Pascals


My reduced equation for use in data smoothing and sensor fusion:

Density of humid air in kg/m^3 as a function of p in Pascals, rho in percent relative humidity, and T in deg C

Goncz, 2018

The development proceeds on the Samsung Note 3 smartphone platform with all available Android sensors, a docking station, a speakerphone / music connection, and a modified bright yellow hat for carrying the smartphone on top of the rider's head for best GPS reception, or frontally to record video or time lapse photography during a route. Unfortunately, this is not a weatherproof phone. Our weatherproof choice is the Rugy Pro but it lacks several important sensors. The search continues for an instrumented weatherproof phone or a weather case for the Note 3. The Note 3 can output to an HDMI monitor so it remains at the top of the list; during lectures, unlike a conventional smartphone, phablets and tablets indicate the pen position with a cursor, guiding the audience's attention.