Rotary distance measurement plus charging

Community Projects
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Thinking about a new project but I am not sure how to do two parts of it. The project is for automatic logging of treadmill distance. I was thinking perhaps I could add a crank charger and charge a LiPo at the same time, creating a completely wireless solution.

I was initially thinking about using the Particle Photon (https://www.sparkfun.com/products/13774 … 3-60679017) with the battery shield (https://www.sparkfun.com/products/13626).

On to the main questions:

  • Is my best bet to just buy a USB crank charger from Amazon, or should I consider some other method of charging?

    I figured a wheel running on the treadmill with a rotary encoder was the best way to measure the distance. Any other methods I should consider?


    • As you may see, my thought process is I can combine the rotary encoder with a crank charger. Has anyone done something like this before? I am open to any feedback or ideas to help me down the right path.

    2

    I’d use two LiPo batteries. Charge one, use one.

    Mechanical generator will be a kludge and a PITA.

    If you must: Consider a bicycle generator like this, or search for better fit:

    http://www.amazon.com/Pyle-PBDNC10-Whee … +generator

    Have it charge the LiPo in the microprocessor.

    Generator → 3.3V regulator → microprocessor.

    distance: a small disc magnet affixed to treadmill’s moving belt. Hall-effect sensor on treadmill base. Connects to microprocessor. Count pulses, do math.

    I’d use a small/simple microprocessor like a tiny Arduino (or PJRC.com Teensy 2 or a low cost ARM Teensy 3 LC). If you just network this, use an ESP8266 board.

    Or get a treadmill after-market add-on for display.

    Or a new treadmill with distance display built-in!

    3

    Thanks for the feedback.

    I am thinking I may start out by skipping the battery and charging. The treadmill has to be plugged in, so power shouldn’t be difficult to access after all.

    My goal is to make something that some of my co-workers could just stick on to their own treadmills, so I don’t want to have to recalculate the distance for every person.

    Also, I am not interested in the display, but for automatically posting the distance traveled to a web service every day. That is why I was thinking the Particle would be a good choice with the included wi-fi.