I tried the following:
public void read() throws ConnectionLostException, InterruptedException {
ioio.beginBatch();
leftStrobe.write(false);
leftStrobe.write(true);
leftStrobe.write(false);
leftInput = ioio.openPulseInput(LEFT_ULTRASONIC_INPUT_PIN,
PulseMode.POSITIVE);
ioio.endBatch();
leftDistance = (int) (leftInput.getDurationBuffered() * 1000000);
leftInput.close();
SystemClock.sleep(100);
dashboard.log(leftDistance + "");
}
It makes one reading and then hangs up. How do I time out if I want stop
waiting?
I put the scope on the sensor and discovered that I am reading alternately
both the trigger pulse and the echo pulse...most often the trigger pulse.
On Tuesday, April 22, 2014 5:05:23 PM UTC-7, Ytai wrote:
>
> No, there isn't, and even if there were, I'm not sure this will actually
> do what you want.
> Have you tried the hack I recommended on the previous post?
>
>
> On Mon, Apr 21, 2014 at 8:36 PM, Vic Wintriss
> <[email protected]<javascript:>
> > wrote:
>
>> 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]<javascript:>>
>> 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]<javascript:>
>> > 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)
>>>> throwsConnectionLostException, InterruptedException
>>>>
>>>> {
>>>>
>>>> ioio.beginBatch();
>>>>
>>>> strobe.write(true);
>>>>
>>>> strobe.write(false);
>>>>
>>>> ioio.endBatch();
>>>>
>>>> this.leftDistance = input.getDuration();
>>>>
>>>> }
>>>>
>>>>
>>>> public float getLeftDistance()
>>>>
>>>> {
>>>>
>>>> return leftDistance;
>>>>
>>>> }
>>>>
>>>> }
>>>>
>>>
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