Shop OBEX P1 Docs P2 Docs Learn Events
cycling computer help — Parallax Forums

cycling computer help

Timp999Timp999 Posts: 1
edited 2009-12-23 13:49 in BASIC Stamp
i am a·senior in high·school·and have always been intrested in robotics and electronics.·so for my senior project i decided to make a cycling computer that would display distance and velocity. after a little reaserch i decided that i would use a hall-effect transistor and a magnet to count the rotations of the front wheel, and have a basic stamp microcontroler do the calculations requiered and output the data to a display

here are the problems that i have encountered
·····-having no previous experience with basic stamp i am a novice at programing it
·····- i cannot find a way for it to count the pulses that would come from the hall- effect transistor
····

·any help would be apreciated

Comments

  • Mike GreenMike Green Posts: 23,101
    edited 2009-12-23 00:34
    Start with the "What's a Microcontroller?" tutorial from Parallax, add the "BASIC Stamp Syntax and Reference Manual". For the first, go to the main Parallax website and click on "Downloads" then "Stamps in Class Downloads". For the 2nd, start with the same webpage and click on "Resources", then "BASIC Stamp Documentation".

    Generally, a Hall-effect sensor needs a power and ground connection (usually +5V and 0V/ground). It has an output pin which is usually an "open-collector" which needs a pullup resistor. Read the Wikipedia on "open collector" and "pull up resistor". Typically, 4.7K or 10K is used between the output pin and +5V. You can connect a Stamp I/O pin to that and use the COUNT statement to count the number of pulses in a specified period of time. Read the chapter in the Reference Manual on the COUNT statement.
  • dexfdexf Posts: 7
    edited 2009-12-23 13:49
    Timp999:

    A quick thought:

    I believe you are making the wheel sensor part of your project more complicated that it needs to be. Most bike computers use a simple reed switch triggered by a magnet. The cost of an entire bike computer is less than $10 from Amazon.· Take a look at the Schwinn computer. It would be hard to assemble just the wheel sensor part for less than that and you get the switch and magnet mounting arrangments along with the deal.

    For example, take a look at how I did just this for my Altitude project here:

    http://www.parallax.com/tabid/818/Default.aspx

    Sensing the wheel rotation is just a switch closure.

    Just a thought.

    Dex
Sign In or Register to comment.