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gyro sensors — Parallax Forums

gyro sensors

science_geekscience_geek Posts: 247
edited 2008-09-11 01:13 in Propeller 1
i need 2 gyros that can read when a car bounces up and down, and when it turns left and right, and needs to be about 100 dollars or less any ideas?

Comments

  • Timothy D. SwieterTimothy D. Swieter Posts: 1,613
    edited 2008-09-08 02:04
    Why does it have to be gyros?

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    Timothy D. Swieter, E.I.

    www.brilldea.com·- Prop Blade, LED Painter, RGB LEDs, uOLED-IOC, eProto fo SunSPOT, BitScope
    www.sxmicro.com - a blog·exploring the SX micro
    www.tdswieter.com
  • LeonLeon Posts: 7,620
    edited 2008-09-08 04:00
    Don't you need an accelerometer for the up/down bouncing?

    Leon

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    Amateur radio callsign: G1HSM
    Suzuki SV1000S motorcycle
  • TimmooreTimmoore Posts: 1,031
    edited 2008-09-08 06:39
    Sparkfun have a board with both for 110, https://www.sparkfun.com/commerce/product_info.php?products_id=741
  • DarrenYDarrenY Posts: 61
    edited 2008-09-08 11:31
    http://www.vti.fi/en/products/accelerometers/automotive_digital/
  • rjo_rjo_ Posts: 1,825
    edited 2008-09-08 13:09
    http://www.parallax.com/Store/Microcontrollers/BASICStampModules/tabid/134/List/1/ProductID/93/Default.aspx?txtSearch=memsic+2125&SortField=ProductName,ProductName

    memsic 2125... object exchange: http://obex.parallax.com/objects/140/

    This is a very sensitive 2 axis accelerometer, which should fit the bill... the only problem is that it is slightly temperature sensitive... it has a pin for temperature correction, but I haven't been able to figure out how to use it.

    The work around is to use either an LM 34(with ADC0831) or a DS1620.... and record the temperature values and the associated drift caused by temperature and then correct your 2125 zero point according to your LM or DS1620 values, either by using a look-up table or an equation. I haven't actually done this... but I can't see why it wouldn't work.

    I have used both the LM34 and the DS1620 and they work great and the objects in the exchange are well documented... and there is a volume of info about both.
  • science_geekscience_geek Posts: 247
    edited 2008-09-08 23:33
    i need it to control servos for a turret, thats why i want gyros, unless an accelerometer could read left and right movement and compensate for the cars turning
  • ElectricAyeElectricAye Posts: 4,561
    edited 2008-09-08 23:38
    Could you use a compass?
  • science_geekscience_geek Posts: 247
    edited 2008-09-09 00:57
    I plan on incorporating the parallax gps mod so thanks a ton, but would i need a gyro for up and down or an accelerometer, im making a turret to mount my gauss gun on just to let you know what its for
  • rjo_rjo_ Posts: 1,825
    edited 2008-09-09 01:23
    I haven't tried it... but I did make a speedometer out of the accelerometer... with no temperature correction and it was convincingly accurate for short runs. With proper temperature correction, I think it would be amazing, but haven't tried it yet. Once you get the speedometer working right... it is just a matter of integration to make it into an odometer... which could also be done with an encoder on your wheel shaft.

    The memsic2125 is just a blast to work with... Radial motion shouldn't be a problem and in terms of up and down (angled motion)... as in moving a barrel up and down to aim... the accelerometer would definitely be good. The compass is only good to about 7 degrees if I recall right... and The GPS suffers from noise at low speed.

    There are a couple of guys working on Gauss Guns in this forum... I would like to see more posted about them.
  • science_geekscience_geek Posts: 247
    edited 2008-09-10 03:08
    since you asked for a post on guassian "rifles" i will tell you about mine, but i have no pics or vids yet, it has about 30 feet of 20 guage wire wrapped around a 1/4 stainless steel tube, the coil is about 3 inches long, i use a flash camera circuit with·15·extra·capacitor·that my physics teacher gave me, i made a bullet on my lathe for it that can go through 2 styrofoam coffee cups, i mounted it to a turret and controlled it with my 4d systems touchscreen that was serial connected to my basic stamp, the stamp was only for the servo control, i fired it with a switch that once fried i revamped it
  • M. K. BorriM. K. Borri Posts: 279
    edited 2008-09-10 06:02
    We did this for a high precision oceanic survey system, there really isn't a cheap solution...

    HOWEVER:

    You could use a servo driver of some sort (like a picaxe08, or even a 555!) to drive 2 RC heli gyros with a neutral servo pulse. Those are very precise and very responsive. Then all you do is read their pulse output and see how much it deviates from neutral.

    (This is what we used during testing until we got the money for a $700 compass+accel module)

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    http://forums.parallax.com/showthread.php?p=650217

    meow, i have my own topic now? (sorta)
  • Cluso99Cluso99 Posts: 18,069
    edited 2008-09-10 07:44
    @science_geek: Careful of programming errors - you don't want that gun firing on you smile.gif
  • LeonLeon Posts: 7,620
    edited 2008-09-10 12:59
    Cluso99 said...
    @science_geek: Careful of programming errors - you don't want that gun firing on you smile.gif

    Something like that happened with a radar-controlled gun prototype here in the UK. A friend of mine worked for the company developing the software. At the first test firing (concrete-filled shells) the gun suddenly slewed to full depression and kept on firing with the shells landing a few hundred yards away. It was OK firing single shells but they didn't compensate properly for the recoil when firing continuously and the control system became unstable.

    Leon

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    Amateur radio callsign: G1HSM
    Suzuki SV1000S motorcycle

    Post Edited (Leon) : 9/10/2008 1:04:57 PM GMT
  • ElectricAyeElectricAye Posts: 4,561
    edited 2008-09-10 14:18
    Cluso99 said...
    @science_geek: Careful of programming errors - you don't want that gun firing on you smile.gif

    You'll shoot your eye out, kid!
  • rjo_rjo_ Posts: 1,825
    edited 2008-09-10 14:46
    Cluso

    I love the whole concept... when you have more, please don't forget us and post it here.

    Leon...

    You have some interesting friends. I'm guessing it was more like a Gaussian sling shot than an actual gun[noparse]:)[/noparse]

    Rich
  • CannibalRoboticsCannibalRobotics Posts: 535
    edited 2008-09-10 22:05
    What about the gyros used for model aircraft? Those are already set up for stabilizing servos. There is a post over on the Stamp forum about this.
    Cheers,
    Jim-

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    A wise man told me; "All electronics are made to work by magic smoke.

    Don't ever let it out as it's·very difficult·to get it back in."
  • Timothy D. SwieterTimothy D. Swieter Posts: 1,613
    edited 2008-09-11 01:13
    M. K. Borri, your idea is an excellent one. When I have read threads like this one or looked at other questions about gyros I first think about a board from SparkFun or spinning a PCB with one, but using RC helicopter gyros sounds a potential solution for many robotic applications.

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    Timothy D. Swieter, E.I.

    www.brilldea.com·- Prop Blade, LED Painter, RGB LEDs, uOLED-IOC, eProto fo SunSPOT, BitScope
    www.sxmicro.com - a blog·exploring the SX micro
    www.tdswieter.com
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