Android and iOS Pedometer Apps

Looking for mobile apps developer that can refine/modify or build a new pedometer integrated to my apps ( android and iOS). The main aim of this project is to develop a pedometer that has a algorithm that can implement better internal step counting. I am open to any idea of using of an external app (that presumably has an API through which to query its data), so far it can be integrated with the current apps. I am looking for pedometer app that will be of low battery usage. I will also like to change the dashboard interfaces to 7-day period and 6-week period charts for both apps. * Note- there is a pedometer already integrated with the apps at the moment and it is being used for contests like faster runner, highest step count. Looking forward to hear from you, if you can do this job. Thanks!