[PD] pduino and FSRs [and one more thing...]
Derek Holzer
derek at umatic.nl
Sat Apr 12 18:02:14 CEST 2008
Some words from the grumbly old man's advice department...
In general, if you aren't 100% sure of the circuit and how it works
(this being a very good example), you'd be best off running the Arduino
on external power rather than power from the USB bus. Unless you want a
non-working USB bus on your computer some day ;-)
You didn't indicate how you were powering the Arduino, so cheerfully
disregard this email if you are already playing safe.
Have a nice day,
d.
Derek Holzer wrote:
> This makes sense. I used some FSRs with a hacked joystick HID device and
> got into some trouble there as well. FSRs have zero resistance when no
> force is applied, so essentially you are short circuiting the 5v
> directly to ground when you plug them in without any force applied. I
> would definitely try a resistor in series with each FSR, that's how I
> did it with the HID joystick, which also crashed (the joystick did not
> function) when the FSR was plugged in without any resistance.
>
> good luck!
> d.
>
> marius schebella wrote:
>> hi nick,
>> did not read through the whole history of this thread but it seems the
>> crash is related to the arduino powering down because of a short
>> circuit. actually the usb port is the one that powers down the arduino
>> or at least disconnect the arduino and that can cause comport to crash.
>> I think you should check your circuit again to make sure there is no
>> short circuit. I am not sure about the phidget but what you need is a
>> resistor connected to ground that circumvents short circuit when you are
>> at the lowest sensor resistance. that is, when you - for example - turn
>> a potentiometer all the way up, it connects the "in" directly to the
>> "out", without any resistance and that causes a short circuit.
>> with the fsr it might be something similar, but it is just a guess.
>> marius.
>>
>> nick burge wrote:
>>> OK this is getting interesting.
>>> I have got the FSRs set up again on my breadboard so I can experiment a
>>> bit. I've tried different baud rates and get the same result...that is
>>> to say a crash in PD.
>>> The FSRs connect to Phidget voltage dividers as recommended by the
>>> suppliers and from the voltage dividers we have 3 wires: analog in, 5v
>>> and ground. Now if I swap the wires they call "analog in" with the 5v
>>> wire on the breadboard and connect again to Pduino I can enable all the
>>> analog inputs in the Arduino object and NO CRASH....
>>> I am no expert in electronics, but I'm sure someone can give me an
>>> explanation as to what is going on.
>>> Looking at the manual for the Phidget voltage dividers I see that in the
>>> proprietry software designed for use with the phidget microprocessor
>>> there is a setting you have to select: namely "Ratiometric" when using
>>> these voltage dividers. Could that have anything to do with it?
>>>
>>> Nick.
>>>
>>> ------------------------------------------------------------------------
>>> *From:* Hans-Christoph Steiner [mailto:hans at eds.org]
>>> *Sent:* 12 April 2008 00:41
>>> *To:* nick burge
>>> *Cc:* Pd List
>>> *Subject:* Re: [PD] pduino and FSRs
>>>
>>>
>>> I use 6 analog inputs all of the time on Mac and Linux. I've never used
>>> 19200 tho. Try using [comport] alone to eliminate anything in [arduino].
>>> Maybe there is a bug in comport on vista?
>>>
>>> .hc
>>>
>>> On Apr 11, 2008, at 3:17 PM, nick burge wrote:
>>>> Thank you Hans, am I being unrealistic in trying to have six analog
>>>> inputs active all at once? I know you said that was a lot of data, but
>>>> I run a fairly powerful laptop with a dual core Centrino processor,
>>>> and Windows task manager reports only a modest demand on the cpu of
>>>> around 30% when I have the patch running and all inputs active, so it
>>>> seems to be an error in timing or syncronisation rather than simply
>>>> overstressing the system that causes this....I've taken the patch
>>>> right down to the basic arduino-test patch, but still the crashes
>>>> occur when I activate more than 2 analog inputs. I'll experiment with
>>>> different baud rates, go back to a usb connection rather than the xbee
>>>> wireless system and keep trying to identify the source of the problem.
>>>> I'll get back to you if I learn anything new. Below is the data
>>>> produced by the event viewer in Windows in case it means anything to you.
>>>> pd.exe
>>>>
>>>> ** 0.0.0.0
>>>>
>>>> ** 47148d16
>>>>
>>>> ** pd.dll
>>>>
>>>> ** 0.0.0.0
>>>>
>>>> ** 47148d15
>>>>
>>>> ** c0000005
>>>>
>>>> ** 00004e04
>>>>
>>>> ** 17ec
>>>>
>>>> ** 01c89bd26543018e
>>>>
>>>> Nick.
>>>>
>>>> ------------------------------------------------------------------------
>>>> *From:* Hans-Christoph Steiner [mailto:hans at eds.org]
>>>> *Sent:* 11 April 2008 18:30
>>>> *To:* nick burge
>>>> *Cc:* Pd List
>>>> *Subject:* Re: [PD] pduino and FSRs
>>>>
>>>>
>>>> Let's keep this on the list since it could be generally useful.
>>>>
>>>> In order to get to the next step, you should try to isolate the
>>>> problem, to see where the crash is actually happening. Otherwise,
>>>> there are far too many possibilities for me to try guessing. Ideally,
>>>> you could make a simple patch that reproduces the crash.
>>>>
>>>> .hc
>>>>
>>>> On Apr 11, 2008, at 3:01 AM, nick burge wrote:
>>>>> Firmata, Pduino and xbees. are all set to communicate at 19200 baud.
>>>>> Nick
>>>>> ------------------------------------------------------------------------
>>>>> *From:* Hans-Christoph Steiner [mailto:hans at eds.org]
>>>>> *Sent:* 10 April 2008 23:57
>>>>> *To:* nick burge
>>>>> *Cc:* Pd List
>>>>> *Subject:* Re: [PD] pduino and FSRs
>>>>>
>>>>>
>>>>> What baud are you running each at? IIRC, the XBee needs a strange value.
>>>>>
>>>>> .hc
>>>>> On Apr 10, 2008, at 5:52 PM, nick burge wrote:
>>>>>> I wish I knew. I'm loading the arduino-test patch with no other
>>>>>> objects or abstractions so as to eliminate other suspects. Still PD
>>>>>> crashes when I enable more than 2 analogIns.
>>>>>> Would it help to speed up or slow down the xbee connection?
>>>>>>
>>>>>> ------------------------------------------------------------------------
>>>>>> *From:* Hans-Christoph Steiner [mailto:hans at eds.org]
>>>>>> *Sent:* 10 April 2008 23:12
>>>>>> *To:* nick burge
>>>>>> *Cc:* Pd List
>>>>>> *Subject:* Re: [PD] pduino and FSRs
>>>>>>
>>>>>>
>>>>>> The code and the electrics are quite separate. If the electrics work
>>>>>> with one firmware, then they'll work with another. The question is,
>>>>>> what is the "it" that grinds to a halt.
>>>>>>
>>>>>> .hc
>>>>>>
>>>>>> On Apr 10, 2008, at 4:17 PM, nick burge wrote:
>>>>>>> Yes, I've got the latest version....maybe a silly question...but
>>>>>>> could it be that Pduino is optimised for sensors working on a
>>>>>>> supply of 5v. because the phidget voltage dividers i've got my FSRs
>>>>>>> attached to come with a potentiometer that alters the resistance of
>>>>>>> the circuit...with pduino i can only activate 2 at a time before it
>>>>>>> all grinds to a halt...on arduino2PD i can activate all six without
>>>>>>> any problem. Strange.
>>>>>>> Nick.
>>>>>>>
>>>>>>> ------------------------------------------------------------------------
>>>>>>> *From:* Hans-Christoph Steiner [mailto:hans at eds.org]
>>>>>>> *Sent:* 10 April 2008 21:51
>>>>>>> *To:* nick burge
>>>>>>> *Cc:* Pd List
>>>>>>> *Subject:* Re: [PD] pduino and FSRs
>>>>>>>
>>>>>>>
>>>>>>> I've never run on Vista before, so I can't say much about that. I
>>>>>>> have run on Debian, Ubuntu, and Mac OS X. It shouldn't matter what
>>>>>>> is generating the data on the arduino, the messages coming to Pd
>>>>>>> via the serial port should be all the same.
>>>>>>>
>>>>>>> Are you using the latest version:
>>>>>>> http://at.or.at/hans/pd/Pduino-0.3.1.zip
>>>>>>>
>>>>>>> .hc
>>>>>>>
>>>>>>> On Apr 10, 2008, at 12:57 PM, nick burge wrote:
>>>>>>>> Hello Hans-Christoph, I am using PD 0.39.3 extended. on a windows
>>>>>>>> vista system. Its PD that crashes, or "stops working" as Vista so
>>>>>>>> nicely puts it, when I connect the FSRs.
>>>>>>>> I have arduino connecting via wireless xbees at 19200 baud.
>>>>>>>> I also use an infra red distance sensor that gives no problem.
>>>>>>>> I've been routing the data from the FSRs through the autoscale object.
>>>>>>>> Maybe I should find a way to reduce the amount of data being
>>>>>>>> sampled...every 40ms for example? How would I do that?
>>>>>>>> Nick.
>>>>>>>> ------------------------------------------------------------------------
>>>>>>>> *From:* Hans-Christoph Steiner [mailto:hans at eds.org]
>>>>>>>> *Sent:* 10 April 2008 17:25
>>>>>>>> *To:* nick burge
>>>>>>>> *Cc:* Pd List
>>>>>>>> *Subject:* Re: [PD] pduino and FSRs
>>>>>>>>
>>>>>>>>
>>>>>>>> Which program crashes? Which version are you using? You will get a
>>>>>>>> lot of data, from 6 sensors, Pduino/Firmata will read them all
>>>>>>>> every 20ms. I have never seen a crash using [arduino], except when
>>>>>>>> I unplug the arduino when Pd is connected to it, so I suspect the
>>>>>>>> problem lies elsewhere.
>>>>>>>>
>>>>>>>> .hc
>>>>>>>>
>>>>>>>> On Apr 10, 2008, at 11:16 AM, nick burge wrote:
>>>>>>>>> I have a little problem using Pduino and some force sensing
>>>>>>>>> resistors that I am using in conjunction with phidget voltage
>>>>>>>>> dividers....they seem to crash the program as soon as I activate
>>>>>>>>> more than 1 at a time.....
>>>>>>>>> Should I be applying some sort of filter to the data stream?
>>>>>>>>> Arduino2PD seems more robust, allowing me to activate all 6
>>>>>>>>> analog inputs at once.
>>>>>>>>> Nick Burge.
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>>>>>>>> ----------------------------------------------------------------------------
>>>>>>>>
>>>>>>>> Looking at things from a more basic level, you can come up with a
>>>>>>>> more direct solution... It may sound small in theory, but it in
>>>>>>>> practice, it can change entire economies. - Amy Smith
>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>> ----------------------------------------------------------------------------
>>>>>>>
>>>>>>> There is no way to peace, peace is the way. -A.J. Muste
>>>>>>>
>>>>>>>
>>>>>>
>>>>>> ----------------------------------------------------------------------------
>>>>>>
>>>>>> There is no way to peace, peace is the way. -A.J. Muste
>>>>>>
>>>>>>
>>>>>
>>>>> ----------------------------------------------------------------------------
>>>>>
>>>>> Mistrust authority - promote decentralization. - the hacker ethic
>>>>>
>>>>>
>>>>
>>>>
>>>> ----------------------------------------------------------------------------
>>>>
>>>> All mankind is of one author, and is one volume; when one man dies,
>>>> one chapter is not torn out of the book, but translated into a better
>>>> language; and every chapter must be so translated.... -John Donne
>>>>
>>>>
>>>
>>>
>>> ----------------------------------------------------------------------------
>>>
>>> You can't steal a gift. Bird gave the world his music, and if you can
>>> hear it, you can have it. - Dizzy Gillespie
>>>
>>>
>>>
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--
derek holzer ::: http://www.umatic.nl ::: http://blog.myspace.com/macumbista
---Oblique Strategy # 20:
"Be extravagant"
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