VS1838B filter reliability problem

Discussion in 'General Electronics Chat' started by drkblog, Jan 30, 2014.

  1. drkblog

    Thread Starter Member

    Oct 4, 2012
    I'm using a VS1838B (which is a TSOP1738 compatible device) for receiving a pulse train of 32 pulses, each pulse is 330µs long and is followed by a space of 450µs, after completing 32 pulses there is a space of 12ms. I'm attaching the wave form here.

    This devices have filters for removing periodic signals. The spaces and the size of the pulses were made according to the available datasheets for these devices. But I came across a strange behavior. I have a VS1838B from an Arduino kit, which is able to receive this signal with no problems. But then I have ten other VS1838B which I bought on eBay which stop receiving the signal after a couple of trains. I tried adding more 38kHz cycles for enlarging the pulses, adding more space between pulses or between trains. I tried reducing the train to 16 pulses too. But no matter what, these receivers don't like the signal.

    Have anyone here used this receivers this way? Any ideas?
  2. alfacliff

    Well-Known Member

    Dec 13, 2013
    sounds like ebay might have a bad batch. try a reputable supplier or get a sample from one.