E = MC squared ! G- metre / recorder.

[Air Ministry .]

 There must be some little electronic contrivance avaliable ,
 at about 3/4 Ounce Wt.  ?

[Alan Hahn]

Eagletree makes a 2 axis accelerometer --although I am not sure it works with their small data recorder. Otherwise you can get some evaluation kits from some manufacturers.

Personally I'd like a 3 axis one so I would always know which way down was. It would make it easier to tag locations in the pattern to measure airspeeds.

[Larry Cunningham]

Analog Devices had a line of low cost solid state accelerometers, dual or single axis, e.g. ADXL210, which fit
into about 1 square inch, you could make up a one cubic inch 3 axis accelerometer. However, I haven't looked
at them in a long time, and it appears that some of the products I had looked at are obsolete. Check out Digikey or similar electronic supply houses for one chip accelerometers. Depends if you are rolling your own or not, whether the chip parts are useful.

Some of the RC helicopter telemetry hardware manufacturers might have what you are looking for, say Eagle Tree may have a module for it, they have data logger systems.

Google, man, Google! ;->

L.

"Be not the first by whom the new are tried, Nor yet the last to lay the old aside." -Alexander Pope

[Air Ministry .]

 Presumably a small electromagnet , mounted in silicon jell.With an adjacend coil and a watch battery would be someway there.

 calibrated in a centrifuge ( variable speed drill ? ) for an electronically dispossed type hobbyist .

[Larry Cunningham]

The solid state ones are tiny and clever, even elegant in concept - G forces distort a semiconductor "micromachine" structure, changing capacitance to modulate pulse width of a digital output. Its circuitry includes an oscillator, signal conditioner, filter, and pulse width modulator..  (Some versions produce a calibrated analog output signal.) Inexpensive, precise and simple to interface; I doubt that rolling your own could be terribly practical here.. ;->

L.

Q. True or False, a pea can last as long as 5,000 years.
A. George Gobel: "Boy, it sure seems that way sometimes."

[John Witt]

"Personally I'd like a 3 axis one so I would always know which way down was."

Alan,

I always wanted to know which way was up.  My airplanes seem to know about down on their own.


John

[Alan Hahn]

"Personally I'd like a 3 axis one so I would always know which way down was."

Alan,

I always wanted to know which way was up.  My airplanes seem to know about down on their own.


John

 
You got me there!

[Air Ministry .]

 THREE dimensions . Most intresting !

 Now has anyone ever USED a 'accelerometor' on a Stunter ?

 Aeroplanes going DOWN ?

 Try vertical  'S'es  , About five going up is average.
 Intrested to see if theres a aship that'd do the same No going DOWN as UP ,
AT its ordinary flying speed .

WARNING ! Three down to five up appears 'average ?

[Alan Hahn]

THREE dimensions . Most intresting !

 Now has anyone ever USED a 'accelerometor' on a Stunter ?

 Aeroplanes going DOWN ?

 Try vertical  'S'es  , About five going up is average.
 Intrested to see if theres a aship that'd do the same No going DOWN as UP ,
AT its ordinary flying speed .

WARNING ! Three down to five up appears 'average ?

I think Igor Burger has.

[phil c]

"Personally I'd like a 3 axis one so I would always know which way down was."

Alan,

I always wanted to know which way was up.  My airplanes seem to know about down on their own.


John

Mine always seem to know where down(the ground is!).

[Alan Hahn]

Mine always seem to know where down(the ground is!).

Just to offer up a little defense of my first comment ( ), I run a data recorder in my electric plane, and can record power settings, and if I set it up, airspeed and altitude (although the altimeter isn't very precise~@3 foot level). One of the interesting things is to see how power/airspeed etc vary according to what the plane is up to. I think a 3 axis accelerometer would help me figure out when the plane is in a corner, climbing vertically,----when I look at the data.

Usually I know what is going on in the actual flight.

[Howard Rush]

Here's a wee accelerometer on an electronic combat engine shutoff.

[Graham Collins]

There are a lot of RC types messing about with UAV and RPV technology some of which comes directly from those tinkering with other type of robotics.  An outfit in the US called Sparkfun has LOTS of neat development, prototyping, sensor tools - many of the software development tools are free and all you need is the idea, the bits and pieces and the time to fit all together and make it work.

For example:

3 axis accelerometers: http://www.sparkfun.com/commerce/categories.php?c=163

2 axis accelerometers: http://www.sparkfun.com/commerce/categories.php?c=162

1 axis accelerometers: http://www.sparkfun.com/commerce/product_info.php?products_id=9332

4/6 Degree of Freedom sensor for UAV / RPV use:

http://www.sparkfun.com/commerce/product_info.php?products_id=9372

Voltage and current sense for those building electric powered planes:

http://www.sparkfun.com/commerce/product_info.php?products_id=9028

I recall seeing a video (youtube maybe) of a control line stunter (russian or east european) which used a gyro (I think - just another form of accelerometer) to control power when maneuvering, kind of like a 4-2-4 break but for an electric. 

The possibilities are endless for the those that want to tinker and it has never been easier.

cheers, Graham in Ottawa Canada
 

[Erik Janssen]

Sparkfun makes a lot of interesting components. One of them is a logomatic data logger where you can choose 8 different analog channels. The big advantage of this device is that it writes the data to a micro SD card.

I stuck a sensor on the back and took 3,3volt from the logger to power the sensor.

I also installed a shunt to the ESC.

The logger was set to a logging frequency of 20Hz and logs a file of U, I, X, Y, Z on every flight it makes. Reading data is done at home where the data from the micro SD card is transferred. As it creates a new folder with data EVERY time I power up I cannot forget to switch on the logger and I do not need a laptop on the flying field.

It has been a great help to develop my sensor timer.

The graph shows tha raw data in excel from sensor and current, the capacity line was calculated. It seems that I have to balance my prop a little better as the sensor even reacts to this vibration.

[Dean Pappas]

Hi Howard,
Which IC is that?
So does the centripetal sensor reliably shut things down in case of a cutaway?
I've wondered about what happens in case of a dropped handle.

take care,
Dean P.

[Howard Rush]

It's a Freescale  MMA2201.

Yes.

It works.  That's how I tested it (with a tether).

[Dean Pappas]

Cool!

   Dean