AVR-Chat

Hi everybody I have been hanging around here for a while, great forum.
Do any of you have any experience with accelerometers? I am thinking of 
a project using an accelerometer to measure angles. The idea is this: 
the accelerometer will be on the outer edge of a wheel. As the wheel is 
turned the position of the accelerometer will move then using a bit of 
grigonometry I can calculate the angle that it has moved through. My 
question is how much accuracy can I get. I will be looking to measure 
fractions of a degree on the wheel aprox 4 inches or 100mm in diameter. 
Doing the maths gives a movement of about .88mm/degree so I would like 
to be able to detect movement of about 0.2mm is this realistic?
Cheers Rich

--- In AVR-Chat@yahoogroups.com, "Richard" <richardt.bradshaw@...> wrote:
>
> Hi everybody I have been hanging around here for a while, great forum.
> Do any of you have any experience with accelerometers? I am thinking of 
> a project using an accelerometer to measure angles. The idea is this: 
> the accelerometer will be on the outer edge of a wheel. As the wheel is 
> turned the position of the accelerometer will move then using a bit of 
> grigonometry I can calculate the angle that it has moved through. My 
> question is how much accuracy can I get. I will be looking to measure 
> fractions of a degree on the wheel aprox 4 inches or 100mm in diameter. 
> Doing the maths gives a movement of about .88mm/degree so I would like 
> to be able to detect movement of about 0.2mm is this realistic?
> Cheers Rich
>

Accelerometers are typically dynamic "sensing devices".  They sense
"change" and are not a good choice for your electronic protractor
device.  A cheap way to go is to use a resistive potentiometer ( a
simple POT ) with a weighted pendulum.  A more sophisticated method of
measuring the tilt angle you desire is to use an optical encoder who's
shaft has a pendulum with a mass at the end. You could get "uber"
fancy with gyroscopes and such, if you wanted to make a real science
project out of it.

M5

--- In AVR-Chat@yahoogroups.com, "Richard" <richardt.bradshaw@...> wrote:
>
> Hi everybody I have been hanging around here for a while, great forum.
> Do any of you have any experience with accelerometers? I am thinking of 
> a project using an accelerometer to measure angles. The idea is this: 
> the accelerometer will be on the outer edge of a wheel. As the wheel is 
> turned the position of the accelerometer will move then using a bit of 
> grigonometry I can calculate the angle that it has moved through. My 
> question is how much accuracy can I get. I will be looking to measure 
> fractions of a degree on the wheel aprox 4 inches or 100mm in diameter. 
> Doing the maths gives a movement of about .88mm/degree so I would like 
> to be able to detect movement of about 0.2mm is this realistic?
> Cheers Rich
>


In other words- you do NOT want an accelerometer for your
inclinometer, you want a "position sensor".

Am I the only one who picked up on this?

M5

----- Original Message ----- 

From: "Richard" <richardt.bradshaw@tesco.net>
To: <AVR-Chat@yahoogroups.com>
Sent: Tuesday, December 02, 2008 7:34 PM
Subject: [AVR-Chat] Accelerometer question


> Hi everybody I have been hanging around here for a while, great forum.
> Do any of you have any experience with accelerometers? I am thinking of
> a project using an accelerometer to measure angles. The idea is this:
> the accelerometer will be on the outer edge of a wheel. As the wheel is
> turned the position of the accelerometer will move then using a bit of
> grigonometry I can calculate the angle that it has moved through. My
> question is how much accuracy can I get. I will be looking to measure
> fractions of a degree on the wheel aprox 4 inches or 100mm in diameter.
> Doing the maths gives a movement of about .88mm/degree so I would like
> to be able to detect movement of about 0.2mm is this realistic?
> Cheers Rich

ADI makes accelerometers that are specifically intended for use as tilt 
sensors.

Leon

Leon Heller
Amateur radio call-sign  G1HSM
Yaesu FT-817ND transceiver
Suzuki SV1000S motorcycle
leon355@btinternet.com
http://www.geocities.com/leon_heller

I worked at an accelerometer transducer company once.   We were  
looking for accuracy over time and discovered why there was a shift  
over time....   We were able to measure the slight inclination of New  
Jersey tilting over it's water table with the phase of the moon!....

Is that accurate enough?  :-)

FYI:  Schaevitz Sensor (Now Measurement Specialty) has most of their  
inclinometers available through standard vendors like Mouser.

BTW:   Some of the toy robot angle sensors are actually MSI sensors.

Regards,

Eric Linn Rabinowitz  N6LG






On Dec 2, 2008, at 1:34 PM, Richard wrote:

Hi everybody I have been hanging around here for a while, great forum.
Do any of you have any experience with accelerometers? I am thinking of
a project using an accelerometer to measure angles. The idea is this:
the accelerometer will be on the outer edge of a wheel. As the wheel is
turned the position of the accelerometer will move then using a bit of
grigonometry I can calculate the angle that it has moved through. My
question is how much accuracy can I get. I will be looking to measure
fractions of a degree on the wheel aprox 4 inches or 100mm in diameter.
Doing the maths gives a movement of about .88mm/degree so I would like
to be able to detect movement of about 0.2mm is this realistic?
Cheers Rich

On Tue, Dec 2, 2008 at 2:34 PM, Richard <richardt.bradshaw@tesco.net> wrote:

>   Hi everybody I have been hanging around here for a while, great forum.
> Do any of you have any experience with accelerometers?
>




Make sure the one you pick will not interfere with the AVR In System
Programming (ISP).  The ones that share I2C/SPI select on a single
pin are prone to this problem.   I have detailed the issue in
my blog at:

http://blog.designer-iii.com/avr_isp_spi/20081116-10511-Digital-MEMS-Accelerometers-will-not-work-with-AVR-ISP-using-SPI

To sumerize it, what happens is that the I2C mode can put a I2C "Ack" on the
ISP
lines if the ISP data happens to look like the Accelerometer's I2C address,
then you can not program and/or verify the program with ISP.




> --
http://www.wearablesmartsensors.com/
http://www.softwaresafety.net/
http://www.designer-iii.com/
http://www.unusualresearch.com/


[Non-text portions of this message have been removed]

> To sumerize it, what happens is that the I2C mode can put a I2C "Ack" on the
> ISP
> lines if the ISP data happens to look like the Accelerometer's I2C address,
> then you can not program and/or verify the program with ISP.
>\

Isolation resistors would fix that problem, you just have to make sure
that the programmer or the AVR wins any argument.

Hi,

a few years ago I built a little self leveling toy that used a solid 
state accelerometer from Maxim and a servo. My cruddy programming 
notwithstanding that sensor was quite capable of measuring angles for 
that particular application. A dual axis accelerometer setup 
perpendicular to Earth should have no trouble measuring absolute angles. 
There might even be an app-note on that subject.

	Sander

Rick wrote:

> 
> 
> --- In AVR-Chat@yahoogroups.com <mailto:AVR-Chat%40yahoogroups.com>, 
> "Richard" <richardt.bradshaw@...> wrote:
>  >
>  > Hi everybody I have been hanging around here for a while, great forum.
>  > Do any of you have any experience with accelerometers? I am thinking of
>  > a project using an accelerometer to measure angles. The idea is this:
>  > the accelerometer will be on the outer edge of a wheel. As the wheel is
>  > turned the position of the accelerometer will move then using a bit of
>  > grigonometry I can calculate the angle that it has moved through. My
>  > question is how much accuracy can I get. I will be looking to measure
>  > fractions of a degree on the wheel aprox 4 inches or 100mm in diameter.
>  > Doing the maths gives a movement of about .88mm/degree so I would like
>  > to be able to detect movement of about 0.2mm is this realistic?
>  > Cheers Rich
>  >
> 
> Accelerometers are typically dynamic "sensing devices". They sense
> "change" and are not a good choice for your electronic protractor
> device. A cheap way to go is to use a resistive potentiometer ( a
> simple POT ) with a weighted pendulum. A more sophisticated method of
> measuring the tilt angle you desire is to use an optical encoder who's
> shaft has a pendulum with a mass at the end. You could get "uber"
> fancy with gyroscopes and such, if you wanted to make a real science
> project out of it.
> 
> M5
> 
>

By the sounds of it an accelerometer is not the solution you want - a
wheel encoder would work much better, I think. The basic idea is, you
have a disc with a pattern of black stripes on it, or slots cut in it,
that selectively blocks light. By counting the number of pulses, you
can figure out how far you've turned. By proper placement of the light
sensor / emitter & using two of them, you can figure out direction of
rotation using quadrature decoding. The resolution on this is limited
only by the number of slots / stripes you can print / detect.

-Randy

On Tue, Dec 2, 2008 at 2:34 PM, Richard <richardt.bradshaw@tesco.net> wrote:
> Hi everybody I have been hanging around here for a while, great forum.
> Do any of you have any experience with accelerometers? I am thinking of
> a project using an accelerometer to measure angles. The idea is this:
> the accelerometer will be on the outer edge of a wheel. As the wheel is
> turned the position of the accelerometer will move then using a bit of
> grigonometry I can calculate the angle that it has moved through. My
> question is how much accuracy can I get. I will be looking to measure
> fractions of a degree on the wheel aprox 4 inches or 100mm in diameter.
> Doing the maths gives a movement of about .88mm/degree so I would like
> to be able to detect movement of about 0.2mm is this realistic?
> Cheers Rich
>
>

the capactive sensors that they use in digital calipers look pretty good.

--- In AVR-Chat@yahoogroups.com, "David VanHorn" <microbrix@...> wrote:
>
>  the capactive sensors that they use in digital calipers look pretty
good.
>

Yes good suggestion.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Consider this-
Take apart a computer serial ball mouse. In there you will see two
optical breaker wheels, one for the X axia and the other Y.  If your
mouse has a scroll wheel, you'll have a similar thing there.  It
wouldn't take much imagination to adapt those parts to a Do It
Yourself inclinometer.  The way these work is the mechanical wheel is
spun and "chops" a beam of invisible infra-red light striking a
photo-transistor.  It does so in a fashion which allow detection
circuitry to determine which direction the wheel is spinning too. 
Cannibalize a mouse for these components and build your inclinometer
from that.

If you are designing a product to market as an inclinometer look at
these sensors:

http://www.spectronsensors.com/tilt.html

They are capacitive.

M5

--- In AVR-Chat@yahoogroups.com, "Rick" <eprom999@...> wrote:
>
> --- In AVR-Chat@yahoogroups.com, "Richard" <richardt.bradshaw@> 
wrote:
> >
> > Hi everybody I have been hanging around here for a while, great 
forum.
> > Do any of you have any experience with accelerometers? I am 
thinking of 
> > a project using an accelerometer to measure angles. The idea is 
this: 
> > the accelerometer will be on the outer edge of a wheel. As the 
wheel is 
> > turned the position of the accelerometer will move then using a 
bit of 
> > grigonometry I can calculate the angle that it has moved through. 
My 
> > question is how much accuracy can I get. I will be looking to 
measure 
> > fractions of a degree on the wheel aprox 4 inches or 100mm in 
diameter. 
> > Doing the maths gives a movement of about .88mm/degree so I would 
like 
> > to be able to detect movement of about 0.2mm is this realistic?
> > Cheers Rich
> >
> 
> Accelerometers are typically dynamic "sensing devices".  They sense
> "change" and are not a good choice for your electronic protractor
> device.  A cheap way to go is to use a resistive potentiometer ( a
> simple POT ) with a weighted pendulum.  A more sophisticated method 
of
> measuring the tilt angle you desire is to use an optical encoder 
who's
> shaft has a pendulum with a mass at the end. You could get "uber"
> fancy with gyroscopes and such, if you wanted to make a real science
> project out of it.
> 
> M5
>
I am working with a 3 axis device. resolution may be a problem since 
there is alot of noise but it is based on gravity. rotary encoders 
would be better.

brian

And most I2C and SPI devices have reset or enable pins that can be 
biased off when the AVR is in reset mode during programming.  Plan 
ahead, it'll work fine.

DLC

David VanHorn wrote:
>> To sumerize it, what happens is that the I2C mode can put a I2C "Ack" on the
>> ISP
>> lines if the ISP data happens to look like the Accelerometer's I2C address,
>> then you can not program and/or verify the program with ISP.
>> \
> 
> Isolation resistors would fix that problem, you just have to make sure
> that the programmer or the AVR wins any argument.
> 
> ------------------------------------
> 
> Yahoo! Groups Links
> 
> 
> 

-- 
-------------------------------------------------
Dennis Clark          TTT Enterprises
www.techtoystoday.com
-------------------------------------------------

Talk about having the answer in the palm of your hand. I think the 
mouse could give enough accuracy. I wanted to play around with an 
accelerometer so I guess I was trying to make the problem fit the 
solution. The project is to make a digital display for a rotary table 
for my milling machine. For those not familier a rotary table sits on 
the milling machine or lathe and allows you to cut at points around a 
centre, cutting gears for example.

There have been lots of interesting answers on this thread many 
thanks and if there any other novel ideas I would love to hear them. 
Rich

--- In AVR-Chat@yahoogroups.com, "Rick" <eprom999@...> wrote:
>
> --- In AVR-Chat@yahoogroups.com, "David VanHorn" <microbrix@> wrote:
> >
> >  the capactive sensors that they use in digital calipers look 
pretty
> good.
> >
> 
> Yes good suggestion.
> 
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Consider this-
> Take apart a computer serial ball mouse. In there you will see two
> optical breaker wheels, one for the X axia and the other Y.  If your
> mouse has a scroll wheel, you'll have a similar thing there.  It
> wouldn't take much imagination to adapt those parts to a Do It
> Yourself inclinometer.  The way these work is the mechanical wheel 
is

> spun and "chops" a beam of invisible infra-red light striking a
> photo-transistor.  It does so in a fashion which allow detection
> circuitry to determine which direction the wheel is spinning too. 
> Cannibalize a mouse for these components and build your inclinometer
> from that.
> 
> If you are designing a product to market as an inclinometer look at
> these sensors:
> 
> http://www.spectronsensors.com/tilt.html
> 
> They are capacitive.
> 
> M5
>

Okay, well now that we know what you are "REALLY" doing and not
building a tilt meter / inclinometer I can say with confidence the
accelerometer is absolutlely to wrong way to go, and so is a
potentiometer and a gyroscope.

It's optical encoder time.  I had a few here built from Hewlett
Packard.  Unfortunately for you I sold them on eBay a while
ago...probably to a guy trying to build something like what you are
thinking of building.

Google optical encoders, and do a search on eBay.  You will then be
pointed in the proper direction.

The mouse parts could be made to work.  You might need to gear-up the
chopper wheel in the mouse so it gives you enough resolution.  What I
mean is have the optical chopper from the mouse send many pulses be
degree of rotation on your milling machine table.  The could involve
sprockets and toothed belts, known as timing belts.

Good luck with your project.

M5


--- In AVR-Chat@yahoogroups.com, "Richard" <richardt.bradshaw@...> wrote:

>
> Talk about having the answer in the palm of your hand. I think the 
> mouse could give enough accuracy. I wanted to play around with an 
> accelerometer so I guess I was trying to make the problem fit the 
> solution. The project is to make a digital display for a rotary table 
> for my milling machine. For those not familier a rotary table sits on 
> the milling machine or lathe and allows you to cut at points around a 
> centre, cutting gears for example.
> 
> There have been lots of interesting answers on this thread many 
> thanks and if there any other novel ideas I would love to hear them. 
> Rich
> 
> --- In AVR-Chat@yahoogroups.com, "Rick" <eprom999@> wrote:
> >
> > --- In AVR-Chat@yahoogroups.com, "David VanHorn" <microbrix@> wrote:
> > >
> > >  the capactive sensors that they use in digital calipers look 
> pretty
> > good.
> > >
> > 
> > Yes good suggestion.
> > 
> > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > Consider this-
> > Take apart a computer serial ball mouse. In there you will see two
> > optical breaker wheels, one for the X axia and the other Y.  If your
> > mouse has a scroll wheel, you'll have a similar thing there.  It
> > wouldn't take much imagination to adapt those parts to a Do It
> > Yourself inclinometer.  The way these work is the mechanical wheel 
> is
> > spun and "chops" a beam of invisible infra-red light striking a
> > photo-transistor.  It does so in a fashion which allow detection
> > circuitry to determine which direction the wheel is spinning too. 
> > Cannibalize a mouse for these components and build your inclinometer
> > from that.
> > 
> > If you are designing a product to market as an inclinometer look at
> > these sensors:
> > 
> > http://www.spectronsensors.com/tilt.html
> > 
> > They are capacitive.
> > 
> > M5
> >
>

If you use the mouse method and place the interrupter disk on the rotation axis of the table, you will avoid problems with backlash, but if you place it on the axis of the rotation handle, assuming, of course, that there is one, the accuracy will be much better.  Remember also that in both cases the optical disc and sensor must be perfectly aligned or the results will be skewed at different angles of rotation.  If you have a rotary table with a handle, it might be easier to just put one or several magnets on the handle and use a magnetic switch to determine handle rotations.  It's not as accurate, but a lot less finicky.


--- On Wed, 12/3/08, Richard <richardt.bradshaw@tesco.net> wrote:

From: Richard <richardt.bradshaw@tesco.net>
Subject: [AVR-Chat] Re: Accelerometer question
To: AVR-Chat@yahoogroups.com
Date: Wednesday, December 3, 2008, 11:48 AM






Talk about having the answer in the palm of your hand. I think the 
mouse could give enough accuracy. I wanted to play around with an 
accelerometer so I guess I was trying to make the problem fit the 
solution. The project is to make a digital display for a rotary table 
for my milling machine. For those not familier a rotary table sits on 
the milling machine or lathe and allows you to cut at points around a 
centre, cutting gears for example.

There have been lots of interesting answers on this thread many 
thanks and if there any other novel ideas I would love to hear them. 
Rich

--- In AVR-Chat@yahoogroup s.com, "Rick" <eprom999@.. .> wrote:
>
> --- In AVR-Chat@yahoogroup s.com, "David VanHorn" <microbrix@> wrote:
> >
> > the capactive sensors that they use in digital calipers look 
pretty
> good.
> >
> 
> Yes good suggestion.
> 
> ~~~~~~~~~~~~ ~~~~~~~~~ ~~~~~~~~~ ~~~~~~~~~ ~~~~~~~~~ ~~~~~
> Consider this-
> Take apart a computer serial ball mouse. In there you will see two
> optical breaker wheels, one for the X axia and the other Y. If your
> mouse has a scroll wheel, you'll have a similar thing there. It
> wouldn't take much imagination to adapt those parts to a Do It
> Yourself inclinometer. The way these work is the mechanical wheel 
is
> spun and "chops" a beam of invisible infra-red light striking a
> photo-transistor. It does so in a fashion which allow detection
> circuitry to determine which direction the wheel is spinning too. 
> Cannibalize a mouse for these components and build your inclinometer
> from that.
> 
> If you are designing a product to market as an inclinometer look at
> these sensors:
> 
> http://www.spectron sensors.com/ tilt.html
> 
> They are capacitive.
> 
> M5
>

 













[Non-text portions of this message have been removed]

Richard,

What kind of accuracy do you need?  Most machining operations will probably need more accuracy than a mouse engine will provide.  You'll also want something that is IP65 or better (sealed against dirt, oil etc) and that is very robust.  A readout that is inconsistent is worse than no readout at all!

I'd probably use an absolute position optical encoder.  We get ours from either PhotoCraft or CUI.  If you're only building one unit you can find one on Ebay for a lot less money.  You could use a incremental encoder as long as you can zero it out.  

Are you building just a readout or are you adding CNC to it?  If you're using a stepping motor you might get by with an open loop system and calculate the rotation since you know the number of steps taken.

  

Regards,


Tim Gilbert
JEM Innovation Inc.
303-926-9053 (office)
303-437-4342 (cell)
720-890-8582 (fax)
www.jeminnovation.com
www.pdksolutions.com

  ----- Original Message ----- 
  From: Richard 
  To: AVR-Chat@yahoogroups.com 
  Sent: Wednesday, December 03, 2008 9:48 AM
  Subject: [AVR-Chat] Re: Accelerometer question


  Talk about having the answer in the palm of your hand. I think the 
  mouse could give enough accuracy. I wanted to play around with an 
  accelerometer so I guess I was trying to make the problem fit the 
  solution. The project is to make a digital display for a rotary table 
  for my milling machine. For those not familier a rotary table sits on 
  the milling machine or lathe and allows you to cut at points around a 
  centre, cutting gears for example.

  There have been lots of interesting answers on this thread many 
  thanks and if there any other novel ideas I would love to hear them. 
  Rich

  --- In AVR-Chat@yahoogroups.com, "Rick" <eprom999@...> wrote:
  >
  > --- In AVR-Chat@yahoogroups.com, "David VanHorn" <microbrix@> wrote:
  > >
  > > the capactive sensors that they use in digital calipers look 
  pretty
  > good.
  > >
  > 
  > Yes good suggestion.
  > 
  > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  > Consider this-
  > Take apart a computer serial ball mouse. In there you will see two
  > optical breaker wheels, one for the X axia and the other Y. If your
  > mouse has a scroll wheel, you'll have a similar thing there. It
  > wouldn't take much imagination to adapt those parts to a Do It
  > Yourself inclinometer. The way these work is the mechanical wheel 
  is
  > spun and "chops" a beam of invisible infra-red light striking a
  > photo-transistor. It does so in a fashion which allow detection
  > circuitry to determine which direction the wheel is spinning too. 
  > Cannibalize a mouse for these components and build your inclinometer
  > from that.
  > 
  > If you are designing a product to market as an inclinometer look at
  > these sensors:
  > 
  > http://www.spectronsensors.com/tilt.html
  > 
  > They are capacitive.
  > 
  > M5
  >



   

[Non-text portions of this message have been removed]

On Wed, Dec 3, 2008 at 1:06 PM, Rick <eprom999@yahoo.com> wrote:
>
> Okay, well now that we know what you are "REALLY" doing and not
> building a tilt meter / inclinometer I can say with confidence the
> accelerometer is absolutlely to wrong way to go, and so is a
> potentiometer and a gyroscope.

That's something I've noticed on here in the past.
When people are more open and detailed about what they are doing, they
tend to get accurate and useful help.

FWIW, you can sometimes find motors with optical encoders attached,
and it might work out well to use the motor as "a really big solid
mount"
A few minutes on the bench to sort out which lead is which, and you're there.

I would say that's true for most Y! groups that are geared towards 
technical assistance :)

David VanHorn wrote:

>
> O
> That's something I've noticed on here in the past.
> When people are more open and detailed about what they are doing, they
> tend to get accurate and useful help.
>
>

Why not use a laser/optical mouse. Non contact, robust, and can resolve >>
1000 lpi... If you decide to use a mouse that is...

-----------------------------------
Bob Tilden, tilden@northwestern.edu
High Energy Physics Group
Northwestern University

-----Original Message-----
From: AVR-Chat@yahoogroups.com [mailto:AVR-Chat@yahoogroups.com] On Behalf
Of Sander Pool
Sent: Wednesday, December 03, 2008 12:29 PM
To: AVR-Chat@yahoogroups.com
Subject: Re: [AVR-Chat] Re: Accelerometer question


I would say that's true for most Y! groups that are geared towards 
technical assistance :)

David VanHorn wrote:
>
> O
> That's something I've noticed on here in the past.
> When people are more open and detailed about what they are doing, they
> tend to get accurate and useful help.
>
>


------------------------------------

Yahoo! Groups Links

RE Optical Mouse as Position Sensor:

Have you ever interfaced an optical mouse IC to an AVR?
I was just about to start such a project for use in linear encoding
of speed and position.(1 axis only)  I would go directly to the sensor 
chip, and
not be bothered with the USB . 

BTW, I don't believe that the light in an optical mouse is a laser - maybe
you are referring to a different breed of mouse.




Robert Tilden wrote:

>
> Why not use a laser/optical mouse. Non contact, robust, and can resolve >>
> 1000 lpi... If you decide to use a mouse that is...
>
> -----------------------------------
> Bob Tilden, tilden@northwestern.edu <mailto:tilden%40northwestern.edu>
> High Energy Physics Group
> Northwestern University
>
> -----Original Message-----
> From: AVR-Chat@yahoogroups.com <mailto:AVR-Chat%40yahoogroups.com> 
> [mailto:AVR-Chat@yahoogroups.com <mailto:AVR-Chat%40yahoogroups.com>] 
> On Behalf
> Of Sander Pool
> Sent: Wednesday, December 03, 2008 12:29 PM
> To: AVR-Chat@yahoogroups.com <mailto:AVR-Chat%40yahoogroups.com>
> Subject: Re: [AVR-Chat] Re: Accelerometer question
>
> I would say that's true for most Y! groups that are geared towards
> technical assistance :)
>
> David VanHorn wrote:
> >
> > O
> > That's something I've noticed on here in the past.
> > When people are more open and detailed about what they are doing, they
> > tend to get accurate and useful help.
> >
> >
>
> ------------------------------------
>
> Yahoo! Groups Links
>
>

Holy cow, I sent this 12/2 and it shows up 12/9? Anyone else getting 
delayed response from Y! or did I end up being moderated here? Did Y! 
flag it as spam?

    Sander

Sander Pool wrote:

>
>
> Hi,
>
> a few years ago I built a little self leveling toy that used a solid
> state accelerometer from Maxim and a servo. My cruddy programming
> notwithstanding that sensor was quite capable of measuring angles for
> that particular application. A dual axis accelerometer setup
> perpendicular to Earth should have no trouble measuring absolute angles.
> There might even be an app-note on that subject.
>
> Sander
>
>

Yahoo Flagged it as spam :(

Just doing the routine maintenance and picked it up

Regards,

Kat.

Sander Pool wrote:

>
>
> Holy cow, I sent this 12/2 and it shows up 12/9? Anyone else getting
> delayed response from Y! or did I end up being moderated here? Did Y!
> flag it as spam?
>
> Sander
>
> Sander Pool wrote:
> >
> >
> > Hi,
> >
> > a few years ago I built a little self leveling toy that used a solid
> > state accelerometer from Maxim and a servo. My cruddy programming
> > notwithstanding that sensor was quite capable of measuring angles for
> > that particular application. A dual axis accelerometer setup
> > perpendicular to Earth should have no trouble measuring absolute angles.
> > There might even be an app-note on that subject.
> >
> > Sander
> >
> >
>
>

You built a self leveling toy using what Maxim accelerometer?  Maxim
part number please?



--- In AVR-Chat@yahoogroups.com, Sander Pool <sander@...> wrote:
>
> 
> Holy cow, I sent this 12/2 and it shows up 12/9? Anyone else getting 
> delayed response from Y! or did I end up being moderated here? Did Y! 
> flag it as spam?
> 
>     Sander
> 
> Sander Pool wrote:
> >
> >
> > Hi,
> >
> > a few years ago I built a little self leveling toy that used a solid
> > state accelerometer from Maxim and a servo. My cruddy programming
> > notwithstanding that sensor was quite capable of measuring angles for
> > that particular application. A dual axis accelerometer setup
> > perpendicular to Earth should have no trouble measuring absolute
angles.

> > There might even be an app-note on that subject.
> >
> > Sander
> >
> >
>

Ah, I got confused. I put one of the other ADXL parts I had in a Maxim 
parts container. It's really an Analog ADXL of some kind. It's hard to 
read the partnumber from the tiny device but it's probably the 202. As I 
recall it has 2 perpendicular sensors in the 2G range but maybe it was 
more. The ADXL322 looks like the most similar device they have now. The 
app note describes how to use it as a tilt sensor.

I shot a little video of the servo trying to stay level as I moved it. 
If I can find it again I'll let you know. It wasn't anything fancy, just 
a proof of concept. It suffered from interference due to the servo and 
avr sharing power.

	Sander

Rick wrote:

> 
> 
> 
> You built a self leveling toy using what Maxim accelerometer? Maxim
> part number please?
>

----- Original Message ----- 

From: "Sander Pool" <sander@tungstentech.com>
To: <AVR-Chat@yahoogroups.com>
Sent: Wednesday, December 10, 2008 1:13 AM
Subject: Re: [AVR-Chat] Re: Accelerometer question


>
> Holy cow, I sent this 12/2 and it shows up 12/9? Anyone else getting
> delayed response from Y! or did I end up being moderated here? Did Y!
> flag it as spam?

Same here. I sent one on the same day as you and it has only just appeared. 
A group I run sometimes gets valid posts identified as spam and I don't 
notice them for a couple of weeks. This probably happened in this case.

Leon

I have used the Memsic 2D accelerometers in a toy magic wand for
many years. The Memsic part is very similar to the AD202, but
cheaper and slower.  The accelerometer, coupled to an AVR,
performs tilt and motion sensing.  The analog interface code is
straight-forward, and I'd be happy to share mine (assembly).

Ken Holt

Sander Pool wrote:

>
>
> Ah, I got confused. I put one of the other ADXL parts I had in a Maxim
> parts container. It's really an Analog ADXL of some kind. It's hard to
> read the partnumber from the tiny device but it's probably the 202. As I
> recall it has 2 perpendicular sensors in the 2G range but maybe it was
> more. The ADXL322 looks like the most similar device they have now. The
> app note describes how to use it as a tilt sensor.
>
> I shot a little video of the servo trying to stay level as I moved it.
> If I can find it again I'll let you know. It wasn't anything fancy, just
> a proof of concept. It suffered from interference due to the servo and
> avr sharing power.
>
> Sander
>
> Rick wrote:
> >
> >
> >
> > You built a self leveling toy using what Maxim accelerometer? Maxim
> > part number please?
> >
>
>