[PD] pduino and FSRs

marius schebella marius.schebella at gmail.com
Sat Apr 12 16:32:39 CEST 2008


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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> 
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