Re: [dorkbotpdx-blabber] dorkbotpdx-blabber Digest, Vol 82, Issue 8

[Mykle Hansen]

Camera bag! My current camera/bag ratio triggers a divide by zero error.

-m-

On Apr 7, 2013, at 3:17 PM, dorkbotpdx-bl...@dorkbot.org wrote:

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> Today's Topics:
>
> 1. Re: Silhouette Cameo update (Erik Walthinsen)
> 2. Re: video dolley is working (Jerry Biehler)
> 3. A puzzle for you. In C. This is just for fun. (David Turnbull)
> 4. Free & cheap stuff on Monday (Apr 8, 2013) (Paul Stoffregen)
> 5. Re: A puzzle for you. In C. This is just for fun. (David Turnbull)
>
> From: Erik Walthinsen <om...@omegacs.net>
> Subject: Re: [dorkbotpdx-blabber] Silhouette Cameo update
> Date: April 4, 2013 5:53:39 PM PDT
> To: "A discussion list for dorkbot-pdx (portland, or)" <dorkbotpd...@dorkbot.org>
> Reply-To: "A discussion list for dorkbot-pdx \(portland, or\)" <dorkbotpd...@dorkbot.org>
>
>
> On 04/04/2013 01:54 PM, Erik Walthinsen wrote:
>> I'm going to do some experiments to see if I can actually square up the
>> cuts that are happening by overshooting the corners (the blade rotates
>> along the vertical axis and "drags" to change direction, afaict). It'd
>> actually look something like a badly compensated scope probe (since I
>> just did that on mine...).
>
> I have to share this update, since it blew me away it worked so well:
>
> I just cut a perfect 0.2mm square in 3mil Mylar, using careful blade-angle pre-cuts and overshoot. It lifted off the adhesive mat with the fragment still on the mat. This is done from my own very simple python script.
>
> It shouldn't be very hard then to get *insanely* accurate stencils made straight from Gerbers (just need to look into existing ways to get convex hulls out of them, or write them).
>
>
>
>
> From: Jerry Biehler <jerry....@gmail.com>
> Subject: Re: [dorkbotpdx-blabber] video dolley is working
> Date: April 5, 2013 12:23:20 AM PDT
> To: "A discussion list for dorkbot-pdx (portland, or)" <dorkbotpd...@dorkbot.org>
> Reply-To: "A discussion list for dorkbot-pdx \(portland, or\)" <dorkbotpd...@dorkbot.org>
>
>
> Neat camera.
>
> Steppers are always rough to some degree, that is why I use servo motors for almost everything. Micro stepping will help. That is what it is intended to do. Keep in mind that the higher the micro step count the lower available torque so you may have to adjust your acceleration setting based on your load. At Laika we ran 10uSteps per step, it seems to be a good trade off area. The cheap little drives skip 10 and jump to 12uSteps if I remember.
>
> I want to put together a camera slide as well sometime. I just picked up a 5D Mark II and want to try some night time lapse.
>
> -Jerry
>
> On Apr 4, 2013, at 4:55 PM, Tom Frisch <t...@tom11.com> wrote:
>
>> Jerry: I'm using a Canon C300, which is a fancy video camera that does great in low light, has a large(ish) sensor, takes Canon stills lenses, and costs way too much.
>>
>> Jim: yes, the stepper is getting a little warm, and there is a pot to adjust current. I haven't mucked with it, but will try.
>>
>> Here's a photo of prototype v1. I used some old spectra fishing line winding on a capstan on the stepper to control position. It works, but as it turns it often clicks on and off the bumps on the pulleys from the 3D printing layers. The stepper also feels a bit notchy, probably the full steps from the controller. I also will be switching over to a pololu with microstepping for the next iteration, so that should give me some smoother motion. Obviously the electronics need some tidying up, and an interface beyond on/off and speed pot. End stops allow for endless ping-pong motion, I'd like to add a joystick or something to get better control, but that will also require that I figure out the AccelStepper library that Paul turned me on to as well.
>>
>> <photo-(10).jpg>
>>
>> --
>> ---------------------------------------
>> Tom Frisch / t...@tom11.com / mobile: 503.473.2801 / www.tom11.com
>> _______________________________________________
>> dorkbotpdx-blabber mailing list
>> dorkbotpd...@dorkbot.org
>> http://music.columbia.edu/mailman/listinfo/dorkbotpdx-blabber
>
>
>
> From: David Turnbull <dtur...@gmail.com>
> Subject: [dorkbotpdx-blabber] A puzzle for you. In C. This is just for fun.
> Date: April 6, 2013 1:39:31 PM PDT
> To: "A discussion list for dorkbot-pdx (portland, or)" <dorkbotpd...@dorkbot.org>
> Reply-To: "A discussion list for dorkbot-pdx \(portland, or\)" <dorkbotpd...@dorkbot.org>
>
>
> Can you explain what this C macro is for? The correct answer will include the type of data it operates on, how it is represented to the macro, and what the macro does to it. I will post a clue tomorrow and the answer after dorkbot on Monday. You can also ask me about it at dorkbot. Feel free to discuss it here on blabber. I will reply if someone posts a complete enough answer but expect me to remain silent otherwise.
>
> #define DATA_L(x) (((x&0x0000000FLU)?1:0)\
> +((x&0x000000F0LU)?1:0)\
> +((x&0x00000F00LU)?1:0)\
> +((x&0x0000F000LU)?1:0)\
> +((x&0x000F0000LU)?1:0)\
> +((x&0x00F00000LU)?1:0))
> #define DATA_C(x) (((x&0x00000002LU)?1:0)\
> +((x&0x00000020LU)?2:0)\
> +((x&0x00000200LU)?4:0)\
> +((x&0x00002000LU)?8:0)\
> +((x&0x00020000LU)?16:0)\
> +((x&0x00200000LU)?32:0))
> #define DATA_6(x) (((x&0x00F00000LU)?4:0)\
> + ((((x&0x00F00000LU)?1:0) & ((x&0x00000002LU)?0:1))?2:0))
> #define DATA(d)((uint8) (d==0)?7:DATA_L(0x##d##LU)\
> + (DATA_C(0x##d##LU) << 8 - DATA_L(0x##d##LU))\
> - DATA_6(0x##d##LU))
>
>
>
>
> From: Paul Stoffregen <pa...@pjrc.com>
> Subject: [dorkbotpdx-blabber] Free & cheap stuff on Monday (Apr 8, 2013)
> Date: April 7, 2013 1:14:26 PM PDT
> To: "A discussion list for dorkbot-pdx (portland, or)" <dorkbotpd...@dorkbot.org>
> Reply-To: "A discussion list for dorkbot-pdx \(portland, or\)" <dorkbotpd...@dorkbot.org>
>
>
> Free stuff:
> ----------
>
> Desktop Microphone stand, similar to http://www.amazon.com/Desk-Drum-Adjustable-BOOM-STAND/dp/B0026QDLDY
>
> Camera bag, http://www.adorama.com/GBSLBK.html
>
> As usual, I'll be brining the free parts pool. I just tossed more parts in... a few bags of many tiny orange LEDs (the ones used on Teensy), a few AVR chips, a DS1337 RTC chip, and other parts.
>
>
> Cheap stuff:
> -----------
>
> Breadboards, full size (830 holes), $2.50 each (I have about 50 available)
>
> Panasonic DVD-LS82 portable DVD player, $30
>
> Panasonic Lumix DMC-FZ20 camera + 2 extra batteries + 58 mm adaptor tube, $50
>
> Canon 250D close-up lens, 58 mm, $50
>
>
>
> This Lumix camera and 250D lens is what I've used most electronics photos. The 250D is amazing for detailed photos of small stuff, not technically "macro" for insects, but really good for circuit boards and projects. Here's a photo it took:
>
> http://www.dorkbotpdx.org/files/images/bus_pirate_dorkbotpdx.jpg
>
> If nobody here wants the camera and dvd player, they're going on Ebay Tuesday morning.
>
>
>
>
>
> From: David Turnbull <dtur...@gmail.com>
> Subject: Re: [dorkbotpdx-blabber] A puzzle for you. In C. This is just for fun.
> Date: April 7, 2013 3:17:43 PM PDT
> To: "A discussion list for dorkbot-pdx (portland, or)" <dorkbotpd...@dorkbot.org>
> Reply-To: "A discussion list for dorkbot-pdx \(portland, or\)" <dorkbotpd...@dorkbot.org>
>
>
> Here's the clue I promised. This demonstrates how information is presented to the macro. The table below is only a sample of a larger table. It's the first 20 entries from the application I will post tomorrow.
>
> const uint8 TABLE[] = {
> DATA(131131),
> DATA(0),
> DATA(0),
> DATA(0),
> DATA(0),
> DATA(133331),
> DATA(31331),
> DATA(313313),
> DATA(0),
> DATA(13131),
> DATA(331133),
> DATA(311113),
> DATA(131313),
> DATA(31131),
> DATA(33333),
> DATA(13333),
> DATA(11333),
> DATA(11133),
> DATA(11113),
> DATA(11111)
> }
>
>
> On Sat, Apr 6, 2013 at 1:39 PM, David Turnbull <dtur...@gmail.com> wrote:
> Can you explain what this C macro is for? The correct answer will include the type of data it operates on, how it is represented to the macro, and what the macro does to it. I will post a clue tomorrow and the answer after dorkbot on Monday. You can also ask me about it at dorkbot. Feel free to discuss it here on blabber. I will reply if someone posts a complete enough answer but expect me to remain silent otherwise.
>
> #define DATA_L(x) (((x&0x0000000FLU)?1:0)\
> +((x&0x000000F0LU)?1:0)\
> +((x&0x00000F00LU)?1:0)\
> +((x&0x0000F000LU)?1:0)\
> +((x&0x000F0000LU)?1:0)\
> +((x&0x00F00000LU)?1:0))
> #define DATA_C(x) (((x&0x00000002LU)?1:0)\
> +((x&0x00000020LU)?2:0)\
> +((x&0x00000200LU)?4:0)\
> +((x&0x00002000LU)?8:0)\
> +((x&0x00020000LU)?16:0)\
> +((x&0x00200000LU)?32:0))
> #define DATA_6(x) (((x&0x00F00000LU)?4:0)\
> + ((((x&0x00F00000LU)?1:0) & ((x&0x00000002LU)?0:1))?2:0))
> #define DATA(d)((uint8) (d==0)?7:DATA_L(0x##d##LU)\
> + (DATA_C(0x##d##LU) << 8 - DATA_L(0x##d##LU))\
> - DATA_6(0x##d##LU))
>
>
>
>
> ........................................................................
> .........dorkbot: people doing strange things with electricity..........
> ......................... http://dorkbot.org ...........................
> ........................................................................

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[J.R. Stoner]

Can you explain what this C macro is for? The correct answer will include
the type of data it operates on, how it is represented to the macro, and
what the macro does to it. I will post a clue tomorrow and the answer after
dorkbot on Monday. You can also ask me about it at dorkbot. Feel free to
discuss it here on blabber. I will reply if someone posts a complete enough
answer but expect me to remain silent otherwise.

Here's the clue I promised. This demonstrates how information is presented
to the macro. The table below is only a sample of a larger table. It's the
first 20 entries from the application I will post tomorrow.

#include <stdio.h>

/* detect and count the symbols in the bit stream.  There is no double-spacing symbol. */

#define DATA_L(x) (((x & 0x0000000F) ? 1 : 0) \

+ ((x & 0x000000F0) ? 1 : 0) \

+ ((x & 0x00000F00) ? 1 : 0) \

+ ((x & 0x0000F000) ? 1 : 0) \

+ ((x & 0x000F0000) ? 1 : 0) \

+ ((x & 0x00F00000) ? 1 : 0))

/* Bit sequence for each word. */

#define DATA_C(x) (((x & 0x00000002LU) ? 1 : 0) \

+ ((x & 0x00000020) ?  2 : 0) \

+ ((x & 0x00000200) ?  4 : 0) \

+ ((x & 0x00002000) ?  8 : 0) \

+ ((x & 0x00020000) ? 16 : 0) \

+ ((x & 0x00200000) ? 32 : 0))

/* Calculate the NRZ parity for completed words.  Last bit == "0" set 6, otherwise 4. */

#define DATA_6(x) (((x & 0x00F00000) ? 4 : 0) + ((((x & 0x00F00000) ? 1 : 0) & ((x & 0x00000002) ? 0 : 1)) ? 2 : 0))

/* Invalid codes result in ^G (BEL).  Justify valid words and strip off the parity. */

#define DATA(d)((unsigned long)(d == 0) ? 7 : DATA_L(d) + (DATA_C(d) << 8 - DATA_L(d)) - DATA_6(d))

unsigned long table[20] =

{

    DATA(131131),	/* H */		/* 01001000 */

    DATA(0),		/* ^G */

    DATA(0),		/* ^G */

    DATA(0),		/* ^G */

    DATA(0),		/* ^G */

    DATA(133331),	/* 6 */		/* 01111000 */

    DATA(31331),	/* 5 */		/* 10110000 */

    DATA(313313),	/* 6 */		/* 10110100 */

    DATA(0),		/* ^G */

    DATA(13131),	/* 5 */		/* 01010000 */

    DATA(331133),	/* 6 */		/* 11001100 */

    DATA(311113),	/* 6 */		/* 10000100 */

    DATA(131313),	/* 6 */		/* 01010100 */

    DATA(31131),	/* 5 */		/* 01001000 */

    DATA(33333),	/* 5 */		/* 01111100 */

    DATA(13333),	/* 5 */		/* 00111100 */

    DATA(11333),	/* 5 */		/* 00011100 */

    DATA(11133),	/* 5 */		/* 00001100 */

    DATA(11113),	/* 5 */		/* 00000100 */

    DATA(11111)		/* 5 */		/* 00000000 */

};

/*

 * The resulting sequence is:

 * 00  131131 _-_---_-_---_ 63

 * 01       0 _____________ 07

 * 02       0 _____________ 07

 * 03       0 _____________ 07

 * 04       0 _____________ 07

 * 05  133331 _-_---------_ 14

 * 06   31331 ___---_-----_ f4

 * 07  313313 _---_-----_-- 35

 * 08       0 _____________ 07

 * 09   13131 ___-_---_---_ d4

 * 10  331133 _-----_-_---- 24

 * 11  311113 _---_-_-_-_-- 65

 * 12  131313 _-_---_---_-- 43

 * 13   31131 ___---_-_---_ 94

 * 14   33333 ___---------- 64

 * 15   13333 ___-_-------- 84

 * 16   11333 ___-_-_------ 84

 * 17   11133 ___-_-_-_---- e4

 * 18   11113 ___-_-_-_-_-- e4

 * 19   11111 ___-_-_-_-_-_ f4

 */

main(argc,argv)

int	argc;

char	*argv[];

{

	int	i;

	for(i = 0; i < 20; i++)

	{

		printf("%02d  %04x\n",i,table[i]);

	}

}