[Machinekit] Re: installing MachineKit on RPI3

[Masoun Mardini]

I found this from raspberry pi web site 


http://downloads.raspberrypi.org/raspbian/images/raspbian-2017-07-05/
after downloading you must copy it to SD card  above 8GB  using  
win32diskimager  or dd 
command if you work on Mac or linux. there is a lot of youtube videos one 
video for example describe how 
to do it exactly, some reading first wouldn't hurt.

then follow the procedure as stated in machine kit 
got to machinekit website --> documentation --> Getting started -->Setting 
up machinekit on a platform --> installing packages -->5. Debian Jessie on 
arm7 (RPi2) (It will work on RPI3 don't worry). follow the steps 

if don't know anything about linux commands familiarise your self first in 
this subject ( installing raspberry pi is not like installing an 
application in windows )


On Monday, 2 October 2017 13:43:45 UTC+2, fishy wrote: 
>
> I am not sure what you are posting about?
>
> I get the feeling the site you link to has been hacked or is spam?
> my browser shows domoticx.com as a dangerous site and I cannot access it 
> without disabling security?
> I asked a friend who knows about raspberry pi and they said the site looks 
> like it has virus on redistributed versions of the raspbian standard images 
> but there is no changes except malware?
>
> None of your links seem to work and you offered no information about 'the 
> missing library', what is the missing library and how did you fix it?
>
> I get the feeling you are not being helpful, please try to explain so a 
> beginer can workout what needs to be done, I have never used raspberry pi 
> or cnc before so need a little more explanation.
>
>
> On Saturday, 30 September 2017 22:05:28 UTC+1, Masoun Mardini wrote:
>>
>> Hi fishy 
>> try this page 
>> http://domoticx.com/raspberry-pi-sd-image-raspbian-linux-os/
>> the missing library I found during downloading machinekit and installing 
>> it. when I try to install a missing one it's always have version error that 
>> it will not install. but when I used Jessie it worked as a charm just 
>> follow the procedures for RPI2 it will work. 
>> http://www.machinekit.io/docs/getting-started/installing-packages/
>>
>> On Friday, 29 September 2017 20:55:17 UTC+2, fishy wrote:
>>>
>>>
>>>
>>> On Wednesday, 27 September 2017 22:15:14 UTC+1, Masoun Mardini wrote:

 Don’t waste your time on strech use jessie or raspbian 8 
 A ton of missing libraries in strech 
 Just search for that older version for RP2/3 
 And then everything is straight forward
>>>
>>>
>>> Which older version, can you give link to download?
>>>
>>> I see your video in other post shows excellent mototrs running how can 
>>> you did this?
>>>
>>> Also why did other comment from 'mungkie' say stretch install was simple 
>>> with only 1 library need recompile, how much is ton of missing libraries?
>>>
>>>
>>>

-- 
website: http://www.machinekit.io blog: http://blog.machinekit.io github: 
https://github.com/machinekit
--- 
You received this message because you are subscribed to the Google Groups 
"Machinekit" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to machinekit+unsubscr...@googlegroups.com.
Visit this group at https://groups.google.com/group/machinekit.
For more options, visit https://groups.google.com/d/optout.

[Machinekit] Re: installing MachineKit on RPI3

[Masoun Mardini]

First sorry if the website appears like this it didn’t show anything on my mac 
I found it using google search. Try other sites for older versions of raspbian 
I found that all links from raspberry pi site give a link to strech only.
The other link is from machinekit web site installing packages. 
What i did to make it work i installed rasbian 8 jessie then I followed the 
instructions exactly as stated in machine kit site 
Nothing more and nothing less I don’t know what’s happening with your 
installation but there is nothing hidden.
Maybe your friend who knows about raspberry pi can help you with getting 
raspbian 8.

-- 
website: http://www.machinekit.io blog: http://blog.machinekit.io github: 
https://github.com/machinekit
--- 
You received this message because you are subscribed to the Google Groups 
"Machinekit" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to machinekit+unsubscr...@googlegroups.com.
Visit this group at https://groups.google.com/group/machinekit.
For more options, visit https://groups.google.com/d/optout.

Re: [Machinekit] Re: Z tool height setting probe and automation for MPCNC using machinekit and pymachinetalk

[Masoun Mardini]

Then i think you refer to z leveling which used in reprap 3d printers, it takes 
several touch points on surface and then make a file to represent the heat map 
to z levels and use yhem during machining, but I didn’t see anything similar in 
machinekit nor linuxcnc.
Also i have read something about parallelism in the new version that gives you 
a perfect cube whatever skew your machine had.

-- 
website: http://www.machinekit.io blog: http://blog.machinekit.io github: 
https://github.com/machinekit
--- 
You received this message because you are subscribed to the Google Groups 
"Machinekit" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to machinekit+unsubscr...@googlegroups.com.
Visit this group at https://groups.google.com/group/machinekit.
For more options, visit https://groups.google.com/d/optout.

Re: [Machinekit] Re: Z tool height setting probe and automation for MPCNC using machinekit and pymachinetalk

[Tom M]

Looks nice,Is that your machine?
Thats not exactly what I was thinking, but a custom Mcode has some appeal.

On Oct 2, 2017 3:41 AM, "Masoun Mardini"  wrote:

> You mean something like this???
> https://youtu.be/OmOqhB4CsJk
> if so you need to write your own G code program and remap to custom M
> instruction ( note the video is done Linuxcnc but I think it will work on
> machine kit)
>
>
> On Sunday, 1 October 2017 20:26:26 UTC+2, Tom M wrote:
>>
>> My apologies in advance about this long brain-dump.
>> I've been making good progress and having a lot of fun auto-homing
>>  using Charles' HAL
>> gantry component
>> for my
>> dual gantry MPCNC  but now and
>> now I'm ready to take it further. (A MPCNC is a Mostly Printed CNC is a low
>> cost kit that you can make or buy which goes together fairly quick. Here's
>> a link of one that we're putting together at workshop88:
>> https://www.youtube.com/watch?v=N12Rk-Ss3aw )
>> I've been thinking about my next steps for my machine.
>>
>> At this point, I want to focus on V-carve engraving using F-engrave
>>  for generating
>> g-code
>>
>> Some of the issues that I've been running into are:
>>
>>- Setting the Z-tool-offset
>>- Parallelism being the wood surface and x-y plan of the machine.
>>
>>
>> To that end I'm interested making some type of z-axis touch probe and
>> start exploring pymachinetalk
>> .
>> Starting out, I'm probably going to make something simple, along the
>> lines of this:
>>
>> http://www.mycncuk.com/threads/5057-another-tool-hight-setting-proble-%29
>>
>> I like the idea of having some spring to the system that that I wont bury
>> the tool into the tool height setter if I go too far.
>>
>> One thing that I don't like is that I have a wired connection to the
>> pre-setter.  It would be the cat's meow to have the switch wired to a
>> pi-zero with wifi (I have a bunch of RPI's sitting unused) and have it talk
>> to my beaglebone over wifi(or other wireless method)and tell the
>> beaglebone  about its reference height or if it's been touched but I'm
>> getting way ahead of myself here.
>>
>>
>> I really enjoy watching the Hal-gantry component derack to the switches.
>> It's pretty cool which is influencing my thinking here.
>>
>> I want to have the z-offset work flow setting be something like this:
>>
>>1. Manually rough set the z-height to the work
>>   1. (This would be less than the height z-offset probe and
>>   would be a safety to insure that I don't bury the tool when using the 
>> probe)
>>2. raise the z-height and insert the probe above the tool.
>>3. Press a custom button on the axis display, which would lower the
>>z-axis till the switch on the probe is tripped. It would then raise lower
>>to find the exact point.  If a rough distance has been defined and has 
>> been
>>exceeded a fault estop would be generated.
>>4. Have parameters be automatically entered for tool offset.
>>
>>
>> I'm thinking I can use tool/system initially for setting the Z tool
>> offset, but could be extended to calibration of the x-y plane.
>>
>>
>> My questions are:
>>
>>- Does this sound reasonable?
>>   - Is there a more established method for doing what I'm talking
>>   about.
>>- Similar things have been done, but has what I'm talking about been
>>done already?
>>   - If so does anyone have a links to recommended reading or the
>>   magic Google search terms to plug in?
>>
>>
>> --
> website: http://www.machinekit.io blog: http://blog.machinekit.io github:
> https://github.com/machinekit
> ---
> You received this message because you are subscribed to a topic in the
> Google Groups "Machinekit" group.
> To unsubscribe from this topic, visit https://groups.google.com/d/
> topic/machinekit/G-JCTrkPI5w/unsubscribe.
> To unsubscribe from this group and all its topics, send an email to
> machinekit+unsubscr...@googlegroups.com.
> Visit this group at https://groups.google.com/group/machinekit.
> For more options, visit https://groups.google.com/d/optout.
>

-- 
website: http://www.machinekit.io blog: http://blog.machinekit.io github: 
https://github.com/machinekit
--- 
You received this message because you are subscribed to the Google Groups 
"Machinekit" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to machinekit+unsubscr...@googlegroups.com.
Visit this group at https://groups.google.com/group/machinekit.
For more options, visit https://groups.google.com/d/optout.

Re: [Machinekit] Howto create DE10_Nano_SoC_DB25

[Mario Scholz]

Hi,

On 2017-10-02 10:48, schoone...@btinternet.com wrote:

On 02/10/17 07:56, Mario Scholz wrote:

I think there is a misunderstanding. I would like to use Terasic DE10:
http://www.terasic.com.tw/cgi-bin/page/archive.pl?Language=English=1046

Yes, read it quickly and missed the '1',  I don't know what stage the
image creation for the DE10 has got to.


Nevermind. The image I build from sources seems already quite well 
functioning.
Its just the bitstream. I will try the next evenings how far I come on 
my own.
I'm new to FPGA. Going to publish a link with all my documentation and 
scripts

on my website once I succeeded.

Best regards,
 Mario

--
___ __ ___ __ ___ _ __ __ _ __
Mario Scholz  ___/_ __ www :_  www.mario-scholz.de
_/_ __ xmpp: mario at im.trial-n-error.net

--
website: http://www.machinekit.io blog: http://blog.machinekit.io github: 
https://github.com/machinekit
--- 
You received this message because you are subscribed to the Google Groups "Machinekit" group.

To unsubscribe from this group and stop receiving emails from it, send an email 
to machinekit+unsubscr...@googlegroups.com.
Visit this group at https://groups.google.com/group/machinekit.
For more options, visit https://groups.google.com/d/optout.

Re: [Machinekit] intergrate computed torque control (PD controller)

[thangle]

i want to use pulse/dir signal to control position, analog voltage -+10V 
(or another stage ) to control Torque, take position and velocity feedback 
from encoder
  
i have plan to use driver EPS-B1-0D20AA and the servo motor is 
60DNMA1-0D20D. It has the close control loop themselves.With them, do i 
need to make a PD control to warrant position or take position and velocity 
feedback from encoder to make 1 more close control loop? 

Like you said, the output i want is still pulse/dir signal for control 
possition and velocity, analog voltage to control Torque (servo driver 
accept "pulse/dir"), encoder data input go to computer is pulse signal   

I still have many things to learn, hope you spend some time to help me. 
Vào 01:05:44 UTC+7 Thứ Hai, ngày 02 tháng 10 năm 2017, Chris Albertson đã 
viết:
>
>
>
> OK,  you have an AC servo motor.What are the electronics that sit 
> between the motor and the computer?   What motor driver are you using?   
>  Software actually never "sees" the motor only the driver electronics.   
>
> Then the next question:  Is encoder data run to the computer?  I assume it 
> is and you wish to close the loop in software.  However there are servo 
> drivers that close the control loop themselves and then the servo motor 
> looks like a stepper motor to your software.I assume you are not doing 
> this and encoder data goes to the computer.  Is it quadrature with index or 
> something different?
>
> So what does the electronic interface look like.  Software in LinuxCNC 
> sees only this interface
>
> There are many ways to interface a servo.  In the worst case you might be 
> sending PWM to a mosfet h-bridge switch that directly controls current to 
> the motor or what most people do is connect a commercial servo amplifier.   
> Some drivers accept "step and direction" from the computer.   
>
> No one can answer software questions without knowing how the electronics 
> works.
>
>
>
> On Sun, Oct 1, 2017 at 1:49 AM, thangle  > wrote:
>>
>> the arm robot i want to controll is like scara but it has one more dof 
>> (5dof) however it just control 4 axis xyzC (already solved kinematics and 
>> dynamics equation). in order to control it, i will use AC servo (or DC 
>> servo). I think it's possible to use Gcode for planning trajectory.About 
>> ROS, i 'm having plan to use it in future with another robot but for now, i 
>> still want to try control arm robot by linuxcnc
>>
>  
> -- 
>
> Chris Albertson
> Redondo Beach, California
>

-- 
website: http://www.machinekit.io blog: http://blog.machinekit.io github: 
https://github.com/machinekit
--- 
You received this message because you are subscribed to the Google Groups 
"Machinekit" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to machinekit+unsubscr...@googlegroups.com.
Visit this group at https://groups.google.com/group/machinekit.
For more options, visit https://groups.google.com/d/optout.

[Machinekit] Re: Z tool height setting probe and automation for MPCNC using machinekit and pymachinetalk

[Masoun Mardini]

You mean something like this???
https://youtu.be/OmOqhB4CsJk
if so you need to write your own G code program and remap to custom M 
instruction ( note the video is done Linuxcnc but I think it will work on 
machine kit)


On Sunday, 1 October 2017 20:26:26 UTC+2, Tom M wrote:
>
> My apologies in advance about this long brain-dump.
> I've been making good progress and having a lot of fun auto-homing 
>  using Charles' HAL 
> gantry component 
> for my 
> dual gantry MPCNC  but now and 
> now I'm ready to take it further. (A MPCNC is a Mostly Printed CNC is a low 
> cost kit that you can make or buy which goes together fairly quick. Here's 
> a link of one that we're putting together at workshop88: 
> https://www.youtube.com/watch?v=N12Rk-Ss3aw )
> I've been thinking about my next steps for my machine.
>
> At this point, I want to focus on V-carve engraving using F-engrave 
>  for generating 
> g-code  
>
> Some of the issues that I've been running into are:
>
>- Setting the Z-tool-offset
>- Parallelism being the wood surface and x-y plan of the machine.
>
>
> To that end I'm interested making some type of z-axis touch probe and 
> start exploring pymachinetalk 
> .
> Starting out, I'm probably going to make something simple, along the lines 
> of this:
>
> http://www.mycncuk.com/threads/5057-another-tool-hight-setting-proble-%29
>
> I like the idea of having some spring to the system that that I wont bury 
> the tool into the tool height setter if I go too far.
>
> One thing that I don't like is that I have a wired connection to the 
> pre-setter.  It would be the cat's meow to have the switch wired to a 
> pi-zero with wifi (I have a bunch of RPI's sitting unused) and have it talk 
> to my beaglebone over wifi(or other wireless method)and tell the 
> beaglebone  about its reference height or if it's been touched but I'm 
> getting way ahead of myself here.
>
>
> I really enjoy watching the Hal-gantry component derack to the switches.  
> It's pretty cool which is influencing my thinking here.
>
> I want to have the z-offset work flow setting be something like this:
>
>1. Manually rough set the z-height to the work
>   1. (This would be less than the height z-offset probe and would 
>   be a safety to insure that I don't bury the tool when using the probe)
>2. raise the z-height and insert the probe above the tool.
>3. Press a custom button on the axis display, which would lower the 
>z-axis till the switch on the probe is tripped. It would then raise lower 
>to find the exact point.  If a rough distance has been defined and has 
> been 
>exceeded a fault estop would be generated.
>4. Have parameters be automatically entered for tool offset.
>
>
> I'm thinking I can use tool/system initially for setting the Z tool 
> offset, but could be extended to calibration of the x-y plane.
>
>
> My questions are:
>
>- Does this sound reasonable?
>   - Is there a more established method for doing what I'm talking 
>   about.
>- Similar things have been done, but has what I'm talking about been 
>done already?
>   - If so does anyone have a links to recommended reading or the 
>   magic Google search terms to plug in?
>   
>
>

-- 
website: http://www.machinekit.io blog: http://blog.machinekit.io github: 
https://github.com/machinekit
--- 
You received this message because you are subscribed to the Google Groups 
"Machinekit" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to machinekit+unsubscr...@googlegroups.com.
Visit this group at https://groups.google.com/group/machinekit.
For more options, visit https://groups.google.com/d/optout.

Re: [Machinekit] Howto create DE10_Nano_SoC_DB25

[Mario Scholz]

Dear Bas,

thanks for helping me and taking the time.

I'm aware of the two threads. The one you were referring and the 2nd one 
from

Michael Brown on "DE10-DE0-Nano - Invitation to collaborate"

Michael Brown also made support for the DE10-CRAMPS
https://github.com/the-snowwhite/mksocfpga/tree/DE10_Nano_FB_Cramps/HW/QuartusProjects
but it seems to me there is nothing for DE10 and DB25 combo which I'm 
trying
to achieve. I do not have any issues on kernel, or preparing a rootfs 
with machinekit.

That already looks promising on my side.

Best regards,
 Mario

On 2017-10-02 09:42, Bas de Bruijn wrote:

On 2 Oct 2017, at 08:56, Mario Scholz
 wrote:


Hi,

Thanks for your response.

I think there is a misunderstanding. I would like to use Terasic
DE10:


http://www.terasic.com.tw/cgi-bin/page/archive.pl?Language=English=1046

I think this thread may interest you.
https://groups.google.com/forum/m/#!topic/machinekit/fleGyyOwDgE


together with the db25 interface board from Charles Steinkühler:
https://oshpark.com/shared_projects/ZSjsiCUd

In order to use HDMI and db25 interface board I need to reprogram
the FPGA and generate a bitstream+device tree to support both. The
DE0 bitstream files will not work as it didn't included an HDMI
section supported by the DE10. Do you agree?

Nevertheless I loop mounted the image you referred to and found only
DE0 (predecessor of DE10) bitstream biles and dtbs
e.g.
lib/firmware/socfpga/DE0_Nano_SoC_DB25.7I76_7I76_7I76_7I76.rbf
lib/firmware/socfpga/DE0_Nano_SoC_DB25.7I76_7I85S_GPIO_GPIO.rbf
lib/firmware/socfpga/DE0_Nano_SoC_DB25.7I77_7I76_GPIO_GPIO.rbf

Best regards,
Mario

On 2017-10-02 08:13, schoone...@btinternet.com wrote:


You don't need to make your own.



There is an image pre-built here







http://deb.machinekit.io/uploads/de0-nano/debian-8.5-console-armhf-2017-02-14/

 --
website: http://www.machinekit.io blog: http://blog.machinekit.io
github: https://github.com/machinekit
---
You received this message because you are subscribed to the Google
Groups "Machinekit" group.
To unsubscribe from this group and stop receiving emails from it, send
an email to machinekit+unsubscr...@googlegroups.com.
Visit this group at https://groups.google.com/group/machinekit.
For more options, visit https://groups.google.com/d/optout.


--
___ __ ___ __ ___ _ __ __ _ __
Mario Scholz  ___/_ __ www :_  www.mario-scholz.de
_/_ __ xmpp: mario at im.trial-n-error.net

--
website: http://www.machinekit.io blog: http://blog.machinekit.io github: 
https://github.com/machinekit
--- 
You received this message because you are subscribed to the Google Groups "Machinekit" group.

To unsubscribe from this group and stop receiving emails from it, send an email 
to machinekit+unsubscr...@googlegroups.com.
Visit this group at https://groups.google.com/group/machinekit.
For more options, visit https://groups.google.com/d/optout.

Re: [Machinekit] Howto create DE10_Nano_SoC_DB25

[Bas de Bruijn]

> On 2 Oct 2017, at 08:56, Mario Scholz 
>  wrote:
> 
> Hi,
> 
> Thanks for your response.
> 
> I think there is a misunderstanding. I would like to use Terasic DE10:
> http://www.terasic.com.tw/cgi-bin/page/archive.pl?Language=English=1046

I think this thread may interest you.
https://groups.google.com/forum/m/#!topic/machinekit/fleGyyOwDgE

> 
> together with the db25 interface board from Charles Steinkühler:
> https://oshpark.com/shared_projects/ZSjsiCUd
> 
> In order to use HDMI and db25 interface board I need to reprogram the FPGA 
> and generate a bitstream+device tree to support both. The DE0 bitstream files 
> will not work as it didn't included an HDMI section supported by the DE10. Do 
> you agree?
> 
> Nevertheless I loop mounted the image you referred to and found only DE0 
> (predecessor of DE10) bitstream biles and dtbs
> e.g.
> lib/firmware/socfpga/DE0_Nano_SoC_DB25.7I76_7I76_7I76_7I76.rbf
> lib/firmware/socfpga/DE0_Nano_SoC_DB25.7I76_7I85S_GPIO_GPIO.rbf
> lib/firmware/socfpga/DE0_Nano_SoC_DB25.7I77_7I76_GPIO_GPIO.rbf
> 
> Best regards,
> Mario
> 
>> On 2017-10-02 08:13, schoone...@btinternet.com wrote:
>> You don't need to make your own.
>> There is an image pre-built here
>> http://deb.machinekit.io/uploads/de0-nano/debian-8.5-console-armhf-2017-02-14/

-- 
website: http://www.machinekit.io blog: http://blog.machinekit.io github: 
https://github.com/machinekit
--- 
You received this message because you are subscribed to the Google Groups 
"Machinekit" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to machinekit+unsubscr...@googlegroups.com.
Visit this group at https://groups.google.com/group/machinekit.
For more options, visit https://groups.google.com/d/optout.

Re: [Machinekit] Howto create DE10_Nano_SoC_DB25

[Mario Scholz]

Hi,

Thanks for your response.

I think there is a misunderstanding. I would like to use Terasic DE10:
http://www.terasic.com.tw/cgi-bin/page/archive.pl?Language=English=1046

together with the db25 interface board from Charles Steinkühler:
https://oshpark.com/shared_projects/ZSjsiCUd

In order to use HDMI and db25 interface board I need to reprogram the 
FPGA and generate a bitstream+device tree to support both. The DE0 
bitstream files will not work as it didn't included an HDMI section 
supported by the DE10. Do you agree?


Nevertheless I loop mounted the image you referred to and found only DE0 
(predecessor of DE10) bitstream biles and dtbs

e.g.
lib/firmware/socfpga/DE0_Nano_SoC_DB25.7I76_7I76_7I76_7I76.rbf
lib/firmware/socfpga/DE0_Nano_SoC_DB25.7I76_7I85S_GPIO_GPIO.rbf
lib/firmware/socfpga/DE0_Nano_SoC_DB25.7I77_7I76_GPIO_GPIO.rbf

Best regards,
 Mario

On 2017-10-02 08:13, schoone...@btinternet.com wrote:

You don't need to make your own.

There is an image pre-built here

http://deb.machinekit.io/uploads/de0-nano/debian-8.5-console-armhf-2017-02-14/


On 02/10/2017 00:36, Mario Scholz wrote:

Hi,

I bought a DE10 and received a DE0-Nano-DB25 breakout board from Jens, 
a subscriber of this list.


What I did until now was to create the different artifacts such as:
* uboot
* kernel (4.1.33-ltsi)
* rootfs (Debian Jessie)

I used the Altera/Intel toolchain 17.0 to compile a bitstream file 
from the Terasic CD-Rom:

Demonstrations/SoC_FPGA/DE10_NANO_SoC_FB

I can load this demo file and program the FPGA.

What I would like to do next is to compile a bitstream file which 
includes support for DE0-Nano-DB25.


It seems to me this is not yet available.

How can I merge 
https://github.com/machinekit/mksocfpga/tree/master/HW/QuartusProjects/DE0_Nano_SoC_DB25
to the Terasic demonstration project DE10_NANO_SoC_FB easily? Can you 
give me any hints on how to do this?


Best regards,
 Mario



--
___ __ ___ __ ___ _ __ __ _ __
Mario Scholz  ___/_ __ www :_  www.mario-scholz.de
_/_ __ xmpp: mario at im.trial-n-error.net

--
website: http://www.machinekit.io blog: http://blog.machinekit.io github: 
https://github.com/machinekit
--- 
You received this message because you are subscribed to the Google Groups "Machinekit" group.

To unsubscribe from this group and stop receiving emails from it, send an email 
to machinekit+unsubscr...@googlegroups.com.
Visit this group at https://groups.google.com/group/machinekit.
For more options, visit https://groups.google.com/d/optout.