angular speed and gyrometer

[fefenin]

i m sorry but i just realised by reredind the web page taht the new gyro is probably very similar to the one i have exepted it has a 3 volt power suply

here is the link:

http://www.nec-tokinamerica.com/prod...ts/pd-057e.pdf

my mistake

fefenin

[mat janssen]

The spec. says 0,66 mV/deg/sec. maybe this is for your sensor the same value.
This is something you can test by yourselves.

[fefenin]

yes i can see that with my oscillospope and stuff but i have no clue how to handle this in my soft
i have an angular rate i just put it in a variable from 10bit adc i can debug it and see the variation when i move the sensor but after what math can i use to transform that in a rotation angle of for example 180° to move a servo??

fefenin

[mat janssen]

Yes, that is possible.

[fefenin]

i know that is possible but what i ask is how i could do
and if people good in programming (not like me) have some ideas

thank ' s for your help
fefenin

[skimask]

i know that is possible but what i ask is how i could do
and if people good in programming (not like me) have some ideas

thank ' s for your help
fefenin

You probably have to get a book on some pretty good math here.
It's called integration. If I know I've been accelerating for 10 seconds and a rate of 10 feet per second, then I know at the end of 10 seconds I'll be moving 100 feet per second and I'll have travelled 50 ft ('cause I started at 0 and now I'm at 100 and the acceleration was constant).
The big thing with integration is the speed at which you integrate. It doesn't do any good if you look at a signal once a minute 'cause you may have been going 100 mph for 50 seconds of that minute, but may have started and ended that minute at 0 mph. Make any sense? Same thing goes with an angular sensor. If I know I started the time at 0 degrees position and zero degree per second of rotation, and now I know I'm rotating at 10 degrees per second, and now it's one second later, then I should know that I've rotated 5 degrees and I'm rotating at 10 degrees per second. So, in another second, I'll be at 15 degrees position, and still be rotating at 10 degrees per second, assuming I haven't had a change in rotational speed.

Problem with this, is that no matter how good you think your math is, over time, your position will be off (especially using integer math like in PBP). You need some way to reset your position to zero (or some known angle). In the Nintendo Wii, the WiiMote uses those 2 IR LEDs from the sensor bar and the small sensor in the front of the WiiMote for just that...to reset the 'level angle' (for lack of a better term).

So, for this to work effectively, you need, at the very least, a few things:
A tight A/D with lots of bits, a fast sampling rate of your sensor, good floating point math, fast processing speed (a PIC is ok, but a dsPIC would be much better).
But if you're just playing around, trying to get something to work...heck ya, a PIC and all it's internals should be perfect. You just have to write some integrating code like I described above and you're set.
Hope you got a couple of ideas out of this...good or bad

[fefenin]

yes that 's an explaination i'll try to do something with what i have already
so that would be a pic16f88 a 8mhz and it's internal 10bit adc and i should probably set it up with -vref and +vref for better range
i ll try to work on it but it very blur for me i m fearly new on it

thank's again