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46  Using Arduino / Installation & Troubleshooting / Re: Marlin Ramps 1.4 Clay Delta upload problem on: August 30, 2014, 10:04:31 am
EXTRUDERS is defined in Configuration.h, so I can't see why that error would occur. Puzzling.
47  Using Arduino / Microcontrollers / Re: Using an ATtiny85 as SPI Slave on: August 30, 2014, 08:09:33 am
I2C has other problems, and is generally run slower than SPI, but works well on tiny85. I am actually using a tiny45 with 8MHZ internal clock for the OpenBlink (aka "BlinkM") type controllable LEDs, with cyz_rgb firmware.

A limitation of i2c is the number of addresses, unless we use 10 bit addresses, so I was thinking an SPI like protocol (two wire, no slave out) could be used. The WS2811 use one wire protocol, but with tight timing requirements.

Anyway, at about $1.50 or so per unit, the OpenBlink design is not cost-effective for lots of LEDS, I can get WS2812 LEDS for about 30c each, and a 328 can handle a long string of those.
48  Using Arduino / LEDs and Multiplexing / Re: Tileable Noise Function with dynamic period on: August 30, 2014, 05:16:25 am
Yeah, "Noise" in graphics is  a very confusing use of the term! It's really randomized textures, but I guess noise is quicker to say. It produces some impressive results though.

49  Using Arduino / Installation & Troubleshooting / Re: Marlin Ramps 1.4 Clay Delta upload problem on: August 29, 2014, 06:49:41 pm
Have you configured a display in configuration.h?
50  Using Arduino / LEDs and Multiplexing / Re: Tileable Noise Function with dynamic period on: August 29, 2014, 06:44:56 pm
Interesting, I will have to have a play with that! I am planning a cylindrical display.

As for the endpoints, I suggests generating n-1 points then interpolating point [n] as the average of [1] and [n-1].
51  Using Arduino / Programming Questions / Re: MersenneTwister.h Troubleshooting#size on: August 29, 2014, 05:01:46 pm
Do you think that I can change MersenneTwisterFast.h to use long instead of int?

I don't think so, at least not with that code - it is written for 32 bit integers.
52  Using Arduino / Project Guidance / Re: Save encoder data to control stepper on: August 29, 2014, 04:54:22 pm
What sort of resolution are you looking for ? The data rate is what makes the project feasible or not.

Capturing every pulse change and recording the time interval may not be possible on an Uno. I would guess that sampling the position about 100 times a second would reproduce the hand movement accurately enough?

I think for winding, the X axis does not move very quickly. Therefore I would sample the position at a fixed interval, eg. 100/sec. This would give a manageable 120kb of data over 10 minutes. (10*60*100*2 bytes).

If you have an incremental encoder, it produces two pulse outputs out of phase, so you can tell the direction. The Uno CPU does not have a hardware decoder, but it is easy enough to do with an interrupt on change. Each interrupt increments or decrements an internal counter. (The direction is determined by the state of the two encoder lines).

With a timer running at 10ms interval, the internal counter is sampled and written to a buffer. At 10ms rate, you would generate 200 bytes per second, so you could transfer that over serial to a PC. (Assuming 2 bytes per sample, +/-32767 counts).

To generate G-code from the data file, you would need to convert the count values to a position in mm, and the feedrate = dist moved/0.01 * 60 (mm/min).

If 10ms is not enough, you could probably go down to 1ms on an Uno before running into performance problems.

I think as a project it's quite doable, if you are realistic about data rates.
53  Using Arduino / Installation & Troubleshooting / Re: Marlin Ramps 1.4 Clay Delta upload problem on: August 29, 2014, 01:32:04 pm
Marlin includes the SdFat library in its source, you shouldn't need to install a library. So it is probably something else.

But there are hundreds of versions of Marlin, without knowing which source you have it's hard to tell. Posting the original error message would help as well.
54  Products / Arduino Due / Re: Reading Serial Flash Manufacture/Device ID via SPI.transfer on: August 29, 2014, 12:42:40 pm
Your SPI transaction looks good, except that the chip is not responding. Assuming that the clock speed is in spec, we are looking for a hardware problem om the Flash side.

Did you set HOLD and/or RESET  high?
55  Using Arduino / Project Guidance / Re: G Code on Arduino? on: August 29, 2014, 04:18:20 am
Since teacup has built-in code to take data from the serial port it may be possible to modify it so it could get that data from an SD card. The large SD Card data buffer may be a problem. If it worked other teacup users might appreciate your efforts.

SD Cards can be used without the FAT file system (and its large data buffer) but then you are into a very non-standard system.

There is a branch of Teacup with SD/FAT support, might be worth a try -

Probably still need modifying to automatically play/repeat a  file.
56  Using Arduino / Project Guidance / Re: G Code on Arduino? on: August 28, 2014, 06:26:48 pm
I've spent some time developing on teacup and other printer firmwares.

Teacup does not seem to support SD card, as that would be an easy way to inject G-code commands.

The next easiest is to inject characters in the main () function (file mendel.c). Currently it looks like this:

// if queue is full, no point in reading chars- host will just have to wait
if ((serial_rxchars() != 0) && (queue_full() == 0)) {
uint8_t c = serial_popchar();

if you add something like the following psuedocode :
  if queue is not full
        c = get next char from my buffer at next_ptr
       gcode_parse_char (c)
       next_ptr ++
       if next_ptr end of my buffer
           set next_ptr to 0

it will repeatedly run the built-in G-code commands.

You can store a "script" of G-code commands as a simple progmem array something like

PROGMEM char my_gcode [] = "G1 X10 Y10\nG1 X20 Y20\n G1 X0 y0\n";

next_ptr can just be an int, going from 0 to strlen(my_gcode).

If you want to get fancy you could add G-code commands to start/stop your script, run different scripts, react to buttons, etc.

There is a G4 command if you want to put pauses in to the script.
57  General Category / General Discussion / Re: Arduino Newbie on: August 28, 2014, 04:06:14 pm
I think we are talking cross purposes. I didn't mean "why are people picking on Intel" - they seem to be fair game!

What I meant was, there have been several newbies with Galileos, asking how to use them. I am just wondering where and why they got them - giveaways, universities, RS/Farnell, sales reps at work?

Because I think if you went to any Arduino-friendly hobby store/maker type place, people probably wouldn't come out with a Galileo.

Microsoft will be giving away Gen 2 Galileos running Windows, not sure if there is any Arduino involved, but I guess there will be the inevitable questions.

58  Using Arduino / LEDs and Multiplexing / Re: Strange RGB LED on: August 28, 2014, 12:53:53 pm
That was indeed the problem. Kind of nuts. This is the result of having the wrong LED and having it hooked up wrong?  I am expecting to order a lot of 50-100 for a project. Is this type of thing common?

If you buy cheap stuff from China, yes smiley

A colleague bought an iPhone car charger off ebay. Being a curious sort, he opened it up to see what regulation was used. There was none! 12V was wired direct from input to output.

Buying in volume seems to provide an opportunity to hide wrong spec/faulty parts, in some cases I've heard of 50% failure rates.
59  General Category / General Discussion / Re: Arduino Newbie on: August 28, 2014, 12:37:31 pm
I am slightly puzzled where people are picking up on Intel Galileo. Obviously Intel have a big marketing machine and can push sales down lots of existing channels, unlike Arduino which has much different community.

Where Intel's marketing side are succeeding, I agree the engineering side is lacking. The Galileo Gen2 not much better than it's predecessor. The Galileo is not cheap either.

For your application, an AVR Arduino would be fine.
60  Products / Arduino Due / Re: Library for Arduino Due & Serial Flash communication over SPI? on: August 28, 2014, 12:24:26 pm
Some puzzling commits in that repo. The maintainer merges a pull request, then the same day rips out all those changes and adds new stuff which breaks compatibility.  smiley-confuse

I suggest if you take the version at Merge pull request #3 from PaulStoffregen/master it will work ok on Due.
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