accelerometer vs potentiometers

Hello everybody from france :clap:
As much, I discovered X-sim and I would like build a pneumatic simulator with K8055.
At this time the simulator is only on my 3d CAD software but...
I read many topic where many people seem to have problems with the potentiometers
So, why not replace them by a accelerometer (nunchuk hack). Simpler to put in place (under the seat for example)
It's not my idea, I found it in another place ...

The accelerometer is a LIS3L02AL from ST Microelectronics

The datasheet said :

Std usage input voltage 3,3V, X or Y axis 1G(180°) 0,99V and -1G (-180°) 2,31V and 0G 1,66V

link :http://www.st.com/stonline/products/literature/ds/11668.pdf

I use the 5V from the velleman board with tree diodes 1N4148 in series to convert it on 3,3v.

I'm not electronician, so I need help to convert them in the correct value for X-sim (0v to 5v). :

Do you think that it is a good idea ?

ps: sorry for my bad english

Hi papymous,


I have thought before the use of accelerometers for position feedback, but usually they are microscopic SMT parts that require special boards to interface to them. I already have several accelerometers (and gyroscopes) and build some SMT boards to use them in my robots long ago. My accelerometers output Pulse width signal that represents the various angles or accelerations... I have the ADXL202 dual axis accelerometers...

EDIT: By the way my ADXL202 accelerometers also have analog output 0 - 5 volt !!!







Your accelerometer could be difficult to be used as in order to get the full swing of 0 to 3.3 volts you need 180degree rotation! Most simulators don't rotate more than 45 degrees!

Anyway its easy to convert the 3.3volts level to 5volts level with the use of an opamp (LM358) or even with the use of a single transistor (BC547). But I don't know the exact values of the external components (resistors) yet for the drive section. Maybe I'll drop a test on my electronics circuit simulator and see if I can come with a simple solution for you.

Here is a free Java based circuit simulator that can help you experimenting:
http://www.falstad.com/circuit/

Regards, Thanos

Is it possible to use hallsensor for position feedback?
Specifically the ss495a from Honeywell.

hello

thank for these infos and your help

I know, this solution is less precise than the potentiometers but can be sufficient for the feedback towards x-sim ?
It is just experimental.

For the accelerometer , I think the simplest manner is to use the nunchuck pcb. Right some weldings for the X and Y output and the 3,3v input.




Maybe, I can use the TLV 274 present on the velleman board to do that ?
But it's a little hard for me to decripte the AOP datasheet and build a circuit.

Thank Thanos for the link

Regards, papymous

Funny to say that!

I'm working on such solution right now. I have in my hands several SS495A Ratiometric Hall effect sensors... If you place it between two magnets you get an almost linear output 0 - 5v !! And it can work as usual pot if rotating a magnet in front of it. Its the mechanical part that is concerns me as I want to use simple materials for a setup that is easily reproducible from others!





Regards, Thanos

...without reasonable success.

The mass inertia of those accelleration or degree measure sensor internals are definatly an issue, if you want to use it for position measuring in shaking or fast moving simulators.

Xciting for example experienced this problem some time ago, if you guys can remember^^
I wouldnt use such Wii or angle sensors. But decide for yourself.

I think, besides encoders, hallsensors are the best way to go, if you can keep strong magentic fields (valves/solenoids) out of their close range. They dont wear out, are very precise, and the moving part does not need physical contact to the sensor. As well you can put them in place of pots without additional hard or software.

Regards
Christian

Maybe we should rename the topic from accelerometer vs potentiometers to accelerometer vs potentiometers vs hall effect!

:rofl:

MOS mentioned some hall sensors in the rsc.net forum. I think those you are requesting are those, but I am not sure.

Anyway, the ss495a ones should work, as they do output 0.5-4.5 Volt and 2.5V in center position if operated with 5V supply voltage.

http://pdf1.alldatasheet.com/datasheet- ... S495A.html

Regards
Christian

Yes, I saw that and was curious as if it would be easier to setup a hallsensor for position feed back versus with pots. Thanks.

Sorry for hijacking this thread. I will crawl back into my hole now. :tape:

I found these infos on the rfr riton tread
One guy use the nunchuck and another the ADLX

http://www.racingfr.com/forum/index.php ... 814&st=660 (If you speak french)
or
http://bustabourss.blogspot.com/ (for pictures)

It's seems to work !?

thank for remote idea sirnoname (a little more expensive vs nunchuck)

no problem for the hijacking

Who?

I dont say that those Wii sensors or inclinometers arent anygood as an input device. But I have doubts that they work well as a precise position measuring devices in shaking/rumbling situations.

regards
Christian

Hi, anyone has some ideia as using hallsensors or accelerometers to build a 360° position feedback ?? Some tip on reading material will help too...