[PD] Ultrasonic Range Finder

[Martin Peach]

On 2013-03-12 09:32, Julian Brooks wrote:
> Hi Martin,
>
> Is this with Maxbotic and if so which one?  I'm going to be running the
> sensor with an RPi as standalone so presume it's a similar setup (I
> believe comport runs fine on RPi)
>

I use the MB1010 (MaxSonarEZ1). The analog output is very low level and 
also quite noisy, so a RC filter would be a good idea. The serial output 
is RS232 on 0-5V, so you need to invert it before reading it with a 
microcontroller USART input. The format is ASCII but it should be 
readable in Pd: from the output of [comport] you need to make lists of 4 
characters starting with 'R' and convert the last three digits to a 
single float. That actually looks more reliable than the analog but I 
haven't tried it. I attached a patch to do that.

With the Pi you probably need to watch out for voltages above 3.3V on 
the IO pins.

Martin


> Would you mind letting me have a look at a patch for translating the
> input data (if you use/need one).  I know from utilising xbees that the
> input data was tricky to parse - to me anyway.
>
> Cheers,
>
> Julian
>
> On 12 March 2013 13:23, Martin Peach <martin.peach at sympatico.ca
> <mailto:martin.peach at sympatico.ca>> wrote:
>
>     On 2013-03-12 08:58, Julian Brooks wrote:
>
>         Hi,
>
>         I'm after some advice:
>
>         For an installation piece I'd like to do I'm investigating range
>         finder
>         sensors (for outdoors).
>
>         Has anyone experience of the Maxbotic URF's and any tips they'd
>         like to
>         share for getting the data into Pd?
>
>
>     I connect them to the analog inputs of an Arduino and send the data
>     to Pd which reads it using [comport].
>
>     Martin
>
>

-------------- next part --------------
#N canvas 57 434 568 394 10;
#X text 191 61 <-packet starts with the letter 'R';
#X msg 139 88 0;
#X obj 112 117 f 0;
#X obj 112 12 inlet;
#X obj 143 117 + 1;
#X obj 112 142 pack 0 0;
#X text 173 144 <- prefix each character with its index;
#X obj 112 168 route 0 1 2 3;
#X obj 130 206 - 48;
#X obj 170 206 - 48;
#X obj 210 206 - 48;
#X obj 130 241 * 100;
#X obj 170 241 * 10;
#X obj 170 313 +;
#X obj 155 333 +;
#X obj 155 357 outlet;
#X text 247 206 <- convert ASCII digit to integer;
#X text 215 264 <- combine the decimal digits;
#X obj 139 63 route 82;
#X obj 112 37 t b f;
#X text 112 -7 unpacks a stream of characters from a maxbotix sonar
sensor;
#X text 368 342 Martin Peach 2013_03_12;
#X connect 1 0 2 1;
#X connect 2 0 5 0;
#X connect 2 0 4 0;
#X connect 3 0 19 0;
#X connect 4 0 2 1;
#X connect 5 0 7 0;
#X connect 7 1 8 0;
#X connect 7 2 9 0;
#X connect 7 3 10 0;
#X connect 8 0 11 0;
#X connect 9 0 12 0;
#X connect 10 0 14 0;
#X connect 11 0 13 1;
#X connect 12 0 13 0;
#X connect 13 0 14 1;
#X connect 14 0 15 0;
#X connect 18 0 1 0;
#X connect 18 1 5 1;
#X connect 19 0 2 0;
#X connect 19 1 18 0;