Good idea about the logic fix. I'm redoing the interface boards, so I might add that logic. If I am, in fact, reading part of the trigger pulse, is there any way of imposing a short, predictable delay...say 50 microsecs...after the trigger pulse but before the getDuration() read?
On Apr 21, 2014, at 5:12 PM, Ytai Ben-Tsvi <[email protected]> wrote: > Good catch, I forgot about this constraint. > In that case, this (similar to what you've proposed) approach might work: > > beginBatch(); > generatePulse(); > openPulseIn(); > endBatch(); > getDuration(); > closePulseIn(); > > I'd like to emphasize that the fact we have to jump through weird hoops to > get is working is mostly due to the fact that this sensor has a weird > interface. BTW, another thing you can do is use a discrete logic gate to > filter out the ping input pulse from the output. Something like: > clean_out = ping_pin & !ioio_pulse_out_pin > > This will convert the Ping's interface to be similar to the one of the other > sensor I referred you to. > > > > On Mon, Apr 21, 2014 at 3:23 PM, Vic Wintriss <[email protected]> wrote: > I don't think that I can use getDurationBuffered() in this case. The > getDuration() Interface notes say: "...Note that once a pulse is detected, > the next one must have its leading edge at least 5ms after the leading edge > of the current one, or else it will be skipped." The ping pulse is about 50 > microsecs long, and the echo pulse comes about 750 microsecs after the ping > pulse, If I am getting the last part of the ping pulse, the echo pulse will > come too soon for getDurationBuffered() to acquire the echo pulse. Am I > understanding this right? > > > On Sunday, April 13, 2014 7:22:39 PM UTC-7, Vic Wintriss wrote: > I am trying to use the Parallax Ping))) ultrasonic sensor with a ioio V1 > board, using the IOIO00503 library. I get a good looking signal...see the > attached scope view, but the input.getDuration() call returns 16.8 micro > seconds most of the time, called 2 times per second. Every once in a while I > get the proper number. > > Any ideas? Here is the code: > > import ioio.lib.api.DigitalOutput; > > import ioio.lib.api.IOIO; > > import ioio.lib.api.PulseInput; > > import ioio.lib.api.PulseInput.PulseMode; > > import ioio.lib.api.exception.ConnectionLostException; > > > > public class UltraSonicSensors > > { > > private static final int LEFT_ULTRASONIC_INPUT_PIN = 35; > > private static final int LEFT_STROBE_ULTRASONIC_OUTPUT_PIN = 15; > > private final PulseInput leftInput; > > private DigitalOutput leftStrobe; > > private float leftDistance; > > private IOIO ioio; > > > > public UltraSonicSensors(IOIO ioio) throws ConnectionLostException > > { > > this.leftInput = ioio.openPulseInput(LEFT_ULTRASONIC_INPUT_PIN, > PulseMode.POSITIVE); > > this.leftStrobe = ioio.openDigitalOutput(LEFT_STROBE_ULTRASONIC_OUTPUT_PIN); > > this.ioio = ioio; > > } > > > > public void read() throws ConnectionLostException, InterruptedException > > { > > read(leftStrobe, leftInput); > > } > > > > private void read(DigitalOutput strobe, PulseInput input) throws > ConnectionLostException, InterruptedException > > { > > ioio.beginBatch(); > > strobe.write(true); > > strobe.write(false); > > ioio.endBatch(); > > this.leftDistance = input.getDuration(); > > } > > > > public float getLeftDistance() > > { > > return leftDistance; > > } > > } > > > -- > You received this message because you are subscribed to the Google Groups > "ioio-users" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/ioio-users. > For more options, visit https://groups.google.com/d/optout. > > > -- > You received this message because you are subscribed to a topic in the Google > Groups "ioio-users" group. > To unsubscribe from this topic, visit > https://groups.google.com/d/topic/ioio-users/3MDLEEKtejY/unsubscribe. > To unsubscribe from this group and all its topics, send an email to > [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/ioio-users. > For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "ioio-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/ioio-users. For more options, visit https://groups.google.com/d/optout.
