Shop OBEX P1 Docs P2 Docs Learn Events
How do taxicabs keep track of milage? — Parallax Forums

How do taxicabs keep track of milage?

Brian CarpenterBrian Carpenter Posts: 728
edited 2007-02-21 17:53 in General Discussion
I dont know much about the OBD2 but is it possible to get a pulse from the OBD2 for every mile traveled?

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔


It's Only A Stupid Question If You Have Not Googled It First!!

Post Edited (Brian Carpenter) : 2/17/2007 10:00:39 PM GMT

Comments

  • Brian CarpenterBrian Carpenter Posts: 728
    edited 2007-02-17 16:56
    i am trying to make a device that will track milage. kinda like a taxicab. I have 20 different locations that i bill milage to each week. I was looking to make a device that would have twenty buttons, one for each loacation. When i press a button for a location, it will log the odometer reading with the associated number pressed. When a new location is press it will associate the new odometer reading with the old location as an end and the new location as a beginning.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔


    It's Only A Stupid Question If You Have Not Googled It First!!
  • Brian CarpenterBrian Carpenter Posts: 728
    edited 2007-02-18 14:39
    any guesses

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔


    It's Only A Stupid Question If You Have Not Googled It First!!
  • ForrestForrest Posts: 1,341
    edited 2007-02-18 14:46
    I've seen GPS systems used for driving directions and also to track the driving route, time, etc.
  • Brian CarpenterBrian Carpenter Posts: 728
    edited 2007-02-18 20:27
    Is there any way to monitor miles traveled from the vehicle without GPS?

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔


    It's Only A Stupid Question If You Have Not Googled It First!!
  • FranklinFranklin Posts: 4,747
    edited 2007-02-18 21:07
    How about the odometer? (on the dash)

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    - Stephen
  • FranklinFranklin Posts: 4,747
    edited 2007-02-18 21:25
    The ODB-II standard apparently puts out vehicle speed in KPH. you could use this and time to compute distance.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    - Stephen
  • Brian CarpenterBrian Carpenter Posts: 728
    edited 2007-02-18 21:51
    Franklin,
    This is also what i was thinking. Is there access to the odometer through the OBD-II?

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔


    It's Only A Stupid Question If You Have Not Googled It First!!
  • RGuyserRGuyser Posts: 90
    edited 2007-02-18 22:42
    i believe i have been told the cabs use an odometer or tachometer hooked to the engine at some point.. possibly the alternator.. but then, that would not account for the gearbox..... so, it seems a hall sensor and magnet on the tire hub may be rational?

    and instead of 20 buttons, consider an LCD and 2 or 4 buttons!

    a 20 button device is a nightmare!

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    3D & 2D Design - Technical Documentation
    www.robertguyser.com
  • LSBLSB Posts: 175
    edited 2007-02-19 19:54
    The EPA mandates standard sensors for emission equipment monitoring, beyond that the manufacturer may/ may not put sensors on or for about anything they choose (and output accordingly). I'd start with standardized and required sensors (info from EPA or high school auto shop perhaps) then contact specific vehicle manufacturers for additional information. Also, online resources like www.obdii.com may have forums and, undoubtedly, more complete information than you’re likely to get here. That said, I think there would be interest here in how to interface to, or extract the info from the OBDII data stream. Here in Oregon some counties are experimenting with this technology to figure road tax--I know what you're inquiring into is possible.
    Aside, I saw some time ago reasonably priced chips that read this data stream to an ASCII serial output… specific to vehicle manufacturer.
  • PJAllenPJAllen Banned Posts: 5,065
    edited 2007-02-21 01:27
    Here's an "aside" regarding car odometers --

    Honda's had some fuss & bother with odometers thought to be incrementing too quickly on Accords.· But what got my interest was that accuracy can "acceptably" be off by 4%.
  • steve_bsteve_b Posts: 1,563
    edited 2007-02-21 17:40
    On my Jeep TJ I had upgraded from stock 29" tires to 31" tires.
    I borrowed a GPS and found that my speedo was dead-on for the 31" tires.
    So basically my jeep had excessive mileage on it than if the speedo gears were set properly.
    There's always some slop, but it still adds up and reduces the resale value of my vehicle.....anyhow, have talked to other Jeep owners (different models) and some have found similar things!

    Just an FYI!

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    ·

    Steve

    "Inside each and every one of us is our one, true authentic swing. Something we was born with. Something that's ours and ours alone. Something that can't be learned... something that's got to be remembered."
  • John R.John R. Posts: 1,376
    edited 2007-02-21 17:53
    steve_b said...
    On my Jeep TJ I had upgraded from stock 29" tires to 31" tires.
    I borrowed a GPS and found that my speedo was dead-on for the 31" tires.
    So basically my jeep had excessive mileage on it than if the speedo gears were set properly.
    There's always some slop, but it still adds up and reduces the resale value of my vehicle.....anyhow, have talked to other Jeep owners (different models) and some have found similar things!

    Just an FYI!

    There is a tendancy/preference to "bias" the speedometer so that it reads "low" with "standard" sized tires.· This is so that you are not likely to be able to say "well my speedometer said 55".

    This may, or may not (especially in the days of digital dashboards) be directly related to the odometer.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    John R.
    Click here to see my Nomad Build Log
Sign In or Register to comment.