LED Speedometer

Discussion in 'The Projects Forum' started by Llamarama, May 12, 2010.

  1. Llamarama

    Thread Starter Active Member

    Feb 1, 2010
    62
    2
    Hello all, I am trying to find a circuit for a digital speedometer. I have heard various mentions of the March 1977 issue of Popular Electronics containing one, but I have been unsuccessful in finding it.

    Can anyone suggest an alternate circuit as I cannot program at all, and ideally would prefer CMOS/TTL logic.

    Thanks to anyone who can help.

    P.S. This is not homework/assignment work, For that I made a set of active noise reducing headphones!
     
  2. retched

    AAC Fanatic!

    Dec 5, 2009
    5,201
    312
    There are a few on the forum, a quick search will give you some leads.

    Here is a neat 7-segment led speedo:
    http://martybugs.net/electronics/speedo.cgi

    There are some others on the forum. Also, a tachometer circuit can be used as a speedometer with little change.
     
  3. Llamarama

    Thread Starter Active Member

    Feb 1, 2010
    62
    2
    That seems likt the best option, from a tacho i just have to do a little maths to get speed. The main thing that puts me off from this project of the 4553 counter which is almost impossible to get in the UK! Oh well, I'll try and work around this and hopefully it will work!
     
  4. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    This will only be the case if some adjustment is made for each gear. 4000 RPM in first is not going to be the same speed indication as 4000 RPM in fifth.
     
  5. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    4000 series CMOS may have different prefixes for different manufacturers. For example,
    CD is the most common
    HEF is Phillips/NXP
    MC1 is ONsemi/Motorola
     
  6. Llamarama

    Thread Starter Active Member

    Feb 1, 2010
    62
    2
    Sadly only ST Ics are available here and they appear not to make a 4553, yet the 4026 is widely available yet hard to come by everywhere else! :p Swings and roundabouts really!
     
  7. Markd77

    Senior Member

    Sep 7, 2009
    2,803
    594
  8. Llamarama

    Thread Starter Active Member

    Feb 1, 2010
    62
    2
    That's the one! I could have sworn I'd tried RS. Oh well! There's a trade counter nearby at Team Valley, I shall get one hopefully over the next few days! :) Thansk for all your help!
     
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