Digital Counter

Discussion in 'The Projects Forum' started by mkv, May 17, 2009.

  1. mkv

    Thread Starter New Member

    May 17, 2009
    6
    0
    Hello everyone,

    I have fairly limited experience with circuits beyond simple stuff, but I need to set up a counter that will record the number of pulses that goes through another independent circuit and then displays the amount. Due to my limited experience and lack of proper equipment (little more than a soldering iron and a volt/amp meter) I was planning to simply modify something to suit my needs, but its not working. :(

    The circuit im trying to record from is releasing charges from a capacitor to activate a solenoid up to 15 times per second. I went and bough a cheap pedometer to try and use as much of that as possible since it has most everything i need (counter and display), and was planning on using a small relay in parrallel to the solonoid to complete the circuit that causes the pedometer to "count".

    I wired everything up in stages, the pedometer is functioning fine and counts if i manually touch the wires and complete the circut, and the relay is getting tripped when its in parrallel to the solenoid. But when i try it all together I get nothing; no counts are recorded at all. Im guessing the pulse from the external circut is just too quick to trip and relaese the relay for the pedometer circut to pick up... But maybe its something else?

    Anyways, im wondering if anyone on here has any idea of what I can do. Be it salvaging something from what I have, or compleatly designing something new, im all ears.
     
  2. steinar96

    Active Member

    Apr 18, 2009
    239
    4
    Can you post a picture or a drawing of your setup ?
     
  3. mkv

    Thread Starter New Member

    May 17, 2009
    6
    0
    of the pedometer i am using?

    And im kind of thinking i am in way over my head on this one. lol
     
  4. Bernard

    AAC Fanatic!

    Aug 7, 2008
    4,176
    397
    1. Do you have a DC voltage source available?
    2. Is there a common ground between source and pedometer?
    3. What is input resistance of ped.?
    4.What is the voltage on " touched wires "?
    5. How fast can the ped. count? Electronic or mechanical?
    6. Possiblle solution: Use a 555 pulse generator to drive ped.
     
  5. mkv

    Thread Starter New Member

    May 17, 2009
    6
    0
    1) Yes
    2) No
    3) Not quite sure what you mean?
    4) .22 V
    5) This could also be the problem, but im not sure how to figure this out. Which is why i think I may need to start from square one and actually build my own circuit... (and electronic)
    6)Can you give me a bit more info on that? gonna go see what I can find about that now, but ive got no idea what that is

    edit: alright that might solve the input problem on the pedometer... but how would I get that to send the same number of pulses as the solenoid receives?
     
  6. Bernard

    AAC Fanatic!

    Aug 7, 2008
    4,176
    397
    All I can say- it was a prompt response. Do not be afraid of giving us some information.Do you have an ohm meter? Does ped. have two wires for input? If yes to both measure resistance between them. Is there a power source to the ped? AC ?. DC? How many volts to advance ped. count? The 555 IC needs a voltage of 5-15 V , an input signal ,shaped as necessary,and with a few resistors and a cap. can generate a pulse from micro sec. to hours, can drive a load with up to 200mA @ close to supply voltage; all we need is what input signal is available, and what is the load, resistive, or inductive, and maybe more.
     
  7. mkv

    Thread Starter New Member

    May 17, 2009
    6
    0
    Alright, ive been doing some more research (and finishing up school, which involved a lot of studying which is why i took so long to respond, sorry) and I dont think utilizing the counter I have is going to work at all. So now im turning this into a project... and I am detremined to make it work.

    So what i need is a counter that counts 3 digits, and displays at least the hundreds and tens digits. From what ive seen the counter part is not really an issue, but the displaying on a screen might be more diffictult...

    The biggest problem I have is that the thing im counting cycles at around 15hz, and if possible I would like it to be able to count up to 30 Hz... How do i know if the things im looking at can count that fast?
     
  8. tkng211

    Well-Known Member

    Jan 4, 2008
    65
    2
    I think any electronic digital counter can count input pulses with 10-100 Hz. The speed could be too fast for electromechanical counters.
     
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