We have a project that uses 6 distance finders, when we try to call
.getDuration() on more then one all further reading freezes.
protected void setup() throws ConnectionLostException {
// front left pulse and echo
echoPinfl_ = ioio_.openPulseInput(6, PulseMode.POSITIVE);
triggerPinfl_ = ioio_.openDigitalOutput(7);
// front middle pulse and echo
echoPinfm_ = ioio_.openPulseInput(2, PulseMode.POSITIVE);
triggerPinfm_ = ioio_.openDigitalOutput(4);
...
public void loop() throws ConnectionLostException, InterruptedException {
// updates front left sensor
try{
triggerPinfl_.write(false);
Thread.sleep(5);
triggerPinfl_.write(true);
Thread.sleep(1);
triggerPinfl_.write(false);
echosecondsfl_ = (int)(echoPinfl_.getDuration() * 1000 * 1000);
echoDistanceCmfl_ = echosecondsfl_ / 29 / 2;
}catch (ConnectionLostException e) { throw e;}
// updates front middle sensor
try{
triggerPinfm_.write(false);
Thread.sleep(5);
triggerPinfm_.write(true);
Thread.sleep(1);
triggerPinfm_.write(false);
// echosecondsfm_ = (int)(echoPinfm_.getDuration() * 1000 * 1000); //if
this line is commented in all further input stops
// echoDistanceCmfm_ = echosecondsfm_ / 29 / 2;
}catch (ConnectionLostException e) { throw e;}
...
On Friday, May 16, 2014 at 11:03:20 AM UTC-6, Ytai wrote:
>
> Thanks for sharing!
>
>
> On Thu, May 15, 2014 at 9:25 PM, <[email protected] <javascript:>>
> wrote:
>
>> Here is some code that works great with the Parallax Ping))) with the
>> circuit in the file attached (thanks to Ytai):
>>
>> private int read(DigitalOutput strobe, PulseInput input, int inputPin)
>> throws ConnectionLostException, InterruptedException // Order of following
>> statements is very important...do not change
>>
>> {
>> int distance = 0;
>>
>> ioio.beginBatch();
>>
>>
>> strobe.write(true);
>>
>> input = ioio.openPulseInput(inputPin, PulseMode.POSITIVE);
>>
>> ioio.endBatch();
>>
>>
>> SystemClock.sleep(40);
>>
>> strobe.write(false);
>>
>> distance += (int) (input.getDuration() * CONVERSION_FACTOR);
>>
>> input.close();
>>
>>
>> return distance;
>> }
>>
>>
>> On Wednesday, April 30, 2014 10:25:27 AM UTC-7, [email protected]
>> wrote:
>>>
>>> I'll clean up the class and post it. Hope other people can use it.
>>> Works very solidly with the Parallax Ping))) ultrasonic module.
>>> Great suggestion to use only one pin for both input and output. It
>>> would even have saved me a part on the pc boards.
>>>
>>> On Sunday, April 27, 2014 8:24:19 PM UTC-7, Ytai wrote:
>>>>
>>>> Cool. If you can create a nice class for using the PING (where the ctor
>>>> gets a IOIO and two pin numbers, and there's a getDistance() method) and
>>>> share it on this forum, it would be a decent return for our efforts :) As
>>>> a
>>>> side note, since you're doing the open-close trick, you might as well use
>>>> a
>>>> single pin and open-close the digital output as well and not need the
>>>> driver chip, so you can even further simplify both your code and your
>>>> circuit.
>>>>
>>>>
>>>> On Sun, Apr 27, 2014 at 8:19 PM, Vic Wintriss <[email protected]>
>>>> wrote:
>>>>
>>>>> I finally got it to work using your last suggestion. This code works
>>>>> that you recommended works perfectly. Thanks so much for sticking with
>>>>> us.
>>>>> We've got 30 or 40 kids using this code at the International Autonomous
>>>>> Robot Competition (iARoC 2014) coming up at the end of June. Check out
>>>>> iaroc.org.
>>>>>
>>>>> triggerHigh();
>>>>> in = openPulseInput();
>>>>> sleep(20ms); // wait until the pulse input module is ready for a
>>>>> pulse.
>>>>> triggerLow(); // kick off a measurement (falling edge does not
>>>>> trigger the pulse input)
>>>>> duration = in.getDuration();
>>>>> in.close();
>>>>> return duration;
>>>>>
>>>>> On Sunday, April 27, 2014 11:36:53 AM UTC-7, Ytai wrote:
>>>>>
>>>>>> Let me shed some light on the internals of PulseInput:
>>>>>>
>>>>>> - A timer is running on the IOIO set to 200Hz (5ms).
>>>>>> - As soon as the pulse input module is opened, and every time
>>>>>> after a pulse is captured the module will be put in the "ready"
>>>>>> state.
>>>>>> - Every time the 200Hz timer triggers, each "ready" module will
>>>>>> be activated, i.e. put in a state where it is waiting for a new pulse.
>>>>>> - Once activated, the module will wait forever (or until closed)
>>>>>> for a pulse, then measure its duration, then sends the result to the
>>>>>> Android.
>>>>>> - So this means that effectively no matter what the actual pulse
>>>>>> rate is, you will never get more than 200 reports per second. This
>>>>>> has been
>>>>>> done on purpose to prevent a high frequency pulse train from
>>>>>> saturating the
>>>>>> connection between the IOIO and the Android. This also means that
>>>>>> there is
>>>>>> a potential "dead time" of up to 5ms after opening or between pulses,
>>>>>> during which a pulse would not be detected.
>>>>>> - On the Android side, every pulse report finds its way to your
>>>>>> PulseInput object. You can then read it in one of three ways:
>>>>>> - getDuration() will return the last report. It will generally
>>>>>> not block, then only exception is until the first report arrives.
>>>>>> - getDurationSync() will always block until a new report comes
>>>>>> in, then return it. So you can be sure that the report is new.
>>>>>> - getDurationBuffered() pulls pulses one by one from a queue.
>>>>>> When the queue becomes empty it behave like getDurationSync(),
>>>>>> i.e. waits
>>>>>> until a new report comes in.
>>>>>>
>>>>>> The Arduino approach cannot be directly applied to the IOIO API,
>>>>>> since you have to take into account that because of the communication
>>>>>> between the Android and the IOIO, much of the IOIO API has been designed
>>>>>> to
>>>>>> be asynchronous in nature. If you were to bake the PING driver directly
>>>>>> into the IOIO firmware, you can use a similar approach to Arduino's
>>>>>> (although you'd probably want to implement it in a non-blocking way,
>>>>>> since
>>>>>> the IOIO allows everything to be used concurrently). The reason why I
>>>>>> have
>>>>>> not done that is because I tried to focus on generic use-cases rather
>>>>>> than
>>>>>> on one peculiar sensor interface.
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Sun, Apr 27, 2014 at 10:57 AM, Duane DeSieno <[email protected]>
>>>>>> wrote:
>>>>>>
>>>>>>> My confusion is maybe over the way getDuration works.
>>>>>>> Does it delay 5ms before looking for the pulse or does it look
>>>>>>> immediately?
>>>>>>> I put 555 timer on the input pin and set it up for 3.15hz and 25.4%
>>>>>>> duty cycle or an 80.6ms pulse every 317.4ms.
>>>>>>> I called getDuration roughly every 100ms. It did not block and
>>>>>>> returned the same value several times before the next pulse
>>>>>>> occurred(not
>>>>>>> what I expected).
>>>>>>>
>>>>>>> Looked at the Arduino approach to using the PING and they use just
>>>>>>> one pin, changing from output after sending a pulse to ping to an input
>>>>>>> for
>>>>>>> their get duration call.
>>>>>>> Since they don't impose a 5ms delay, they get the duration of the
>>>>>>> return pulse.
>>>>>>>
>>>>>>> Thanks for you help on this.
>>>>>>>
>>>>>>> Duane
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
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>>>>>>>
>>>>>>
>>>>>> --
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>>>>>
>>>>
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>
>
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