Build a cheap weather station using QuickBasic, LPT1 and some Logic

Discussion in 'The Projects Forum' started by smokingwheels, Aug 24, 2013.

  1. smokingwheels

    Thread Starter New Member

    Aug 20, 2011
    I intend to use Quick Basic to do the software with and the Computer's Parallel port to interface to the Logic and sensors running off a laptop.

    I would like to measure Frequency, Period and Contact closures of sensor signals. eg typical Weather Station

    All analog signals would be converted to frequency.

    The period measurement needs to be of sufficient resolution and the signal range could be form .01 Hz to 3 kHz?

    A few Relays would be ok too eg for Class A Evaporation Pan with auto refill.

    Not really sure on the number of channels yet but It would be good to have a few extra options for the future.

    Here is the circuit I have so far.

    For frequency measurement:
    The PC sets V3 to High then starts to clock the ripple counter while counting the number of pluses until the the MR is tripped, then just work out the difference. One of these maybe needed for each input, not sure yet.
  2. ScottWang


    Aug 23, 2012
    Why you don't just connecting the output from Q8 of U1, but added another 4040, any other reason?