Stingray Robot Kit (#28980) and Wheel Encoders

24

Comments

  • edited May 2012 Posts: 0Vote Up0Vote Down

    This is the prototype set in the pic. A *lucky*(?) customer will be getting this prototype in a couple of days to "test drive" with no documentation, no directions, and no code samples, and...and...let's see, what else can't I give them, to make it a real challenge?
    -MattG

    Sounds like a job for Phil or erco - but then again there is no wood...
    Whit+

    "In almost every robotic project I attempt, I am way over my head going into it..." - Carol Lynn Hazlett
  • edited May 2012 Posts: 0Vote Up0Vote Down
    Matt,

    Nice photograph. That picture explains it all.

    That one (or one very similar ) should go on the product page.
  • edited May 2012 Posts: 0Vote Up0Vote Down
    but then again there is no wood...
    There will be...:thumb:


    -Tommy
  • edited May 2012 Posts: 0Vote Up0Vote Down
    Here's the latest pic for the new encoder.

    As shown, the same encoder is used on each Stingray wheel, it's just reversed. The mounting brackets and hardware will be available as a separate kit.

    -MattG

    On the StrayRay mounting kit as pictured you have a little block of plastic for each sensor. What was the consideration for that over just a couple stand-offs?

    ms

    Matt Stemple
    www.StempleLABS.com
  • edited May 2012 Posts: 0Vote Up0Vote Down
    but then again there is no wood
    So you can rest-assured that ol' cellulose boy is OUT of the running...

    Actually, I'm not sure that the "secret customer" is even on these Forums. The recipient is going to be encouraged to give us some updates here, as he "plays with it".

    -MattG
    There will be...:thumb:

    et tu Tomme? Then short-circuit MattG!
    - Matt Gilliland -
    - mattg@parallax.com
    - (916) 624-8333 x3018
    Ask me about the Lifetime Warranty on the Propeller BOE :smile:
  • edited May 2012 Posts: 0Vote Up0Vote Down
    On the StrayRay mounting kit as pictured you have a little block of plastic for each sensor. What was the consideration for that over just a couple stand-offs?
    Great question Stempile.

    My desire for any "retrofit" to a Legacy Product (like the Stingray), is to come up with ways in which there is no need for any modifications to the original Product.

    Normally, standoffs would certainly be easier, but the hole locations on the Encoder Board weren't quite right for alignment to any of the existing holes on the Stingray chassis.

    The Encoder's first order of priority is to be a "drop-in" replacement for the original Position Controller that is currently on the Madeusa and Eddie platforms. I wanted to leverage the design effort to have the same Encoder footprint work in the Stingray too.

    So, the block was a necessary evil because it accommodates the offset of the Encoder mounting holes with the "stock holes" already present on the Stingray -

    Viola! No drilling of new mounting holes required :thumb:

    -MattG

    PS: Yes, I know I spelled a musical instrument :tongue:
    - Matt Gilliland -
    - mattg@parallax.com
    - (916) 624-8333 x3018
    Ask me about the Lifetime Warranty on the Propeller BOE :smile:
  • edited May 2012 Posts: 0Vote Up0Vote Down
    Oh, yeah... DUH. Chris said that at the start of this thread. Forgot. Thanks.

    Matt Stemple
    www.StempleLABS.com
  • edited May 2012 Posts: 0Vote Up0Vote Down
    Hello Matt,

    The encoder disks look pretty thick. How much clearance is there between the encoder and the sensor? If there isn't much then if there is any end play in the motor shaft that can become an issue. I've run into some in the past where a sensor looked ok but when the motor ran back and forth the end of the shaft would move in and out a but and cause the encoder wheel to touch the sensor. I always check that when installing them to ensure there is proper clearance.

    Robert
  • Chris SavageChris Savage Parallax Engineering
    edited May 2012 Posts: 13,737Vote Up0Vote Down
    Stempile wrote: »
    Oh, yeah... DUH. Chris said that at the start of this thread. Forgot. Thanks.

    That's okay...as Matt G. can verify, much of what I say gets forgotten. :innocent:
    Chris Savage
    Engineering Tech, Parallax Inc.
    (916) 624-8333 x3005
    Website / Twitter / Google+
  • edited May 2012 Posts: 0Vote Up0Vote Down
    The encoder disks look pretty thick. How much clearance is there between the encoder and the sensor?
    Hi Robert -
    You're right, they are pretty thick. They're made from .065 delrin. The slot is .118 wide which leaves an optimal clearance of .053 / 2 = .026 per side for clearance.

    I tried thinner material but it tended to "wobble" because of the lack of grip-surface area on the itty-bitty shaft.

    The motor samples I'm working with have <.002 slop in the armature longitudinally, so we should be fine. Of course, we're not going to finalize this until Chris makes the final decision on the motors.

    In the four motors that I've tested (the stock 7.2v units on the standard Stingray), it's a non-issue, they all have the same "slop" - about .002 or so.

    Interesting note on the two-winged sensor disk: It's held onto the shaft by a series of (16) radial slots (.025 long) that are cut around the perimeter of the .070 diameter mounting hole. This resulted in teeny-tiny, algae-like feelers that clamp nice and snugly to the motor shaft - gotta love that laser :thumb:

    -MattG
    - Matt Gilliland -
    - mattg@parallax.com
    - (916) 624-8333 x3018
    Ask me about the Lifetime Warranty on the Propeller BOE :smile:
  • edited May 2012 Posts: 0Vote Up0Vote Down
    Great question Stempile.

    So, the block was a necessary evil because it accommodates the offset of the Encoder mounting holes with the "stock holes" already present on the Stingray -

    Viola! No drilling of new mounting holes required :thumb:

    -MattG
    Maybe not so evil, That block is integral to any kind of hacking Factory Specification Adjustment. :)
    Some free thinking individuals may prefer to drill and tap the installation holes for themselves...


    -Tommy
  • edited May 2012 Posts: 0Vote Up0Vote Down
    Does the height of the blocks match the motor mounting bracket that comes with the Stingray wheel/motor kit if you buy those separately?

    http://www.parallax.com/Store/Robots/RoboticAccessories/tabid/145/CategoryID/22/List/0/SortField/0/Level/a/ProductID/587/Default.aspx

    Just wondering if these will work for other robot platforms that may already be using these wheel/motor kits.

    Robert
  • edited May 2012 Posts: 0Vote Up0Vote Down
    Hey Robert -

    Short answer is "no".
    Long answer is "a different mounting bracket style will" - Just haven't made it yet.

    The idea is to have simple, inexpensive mounting kits for each of the encoders' applications...

    -MattG
    - Matt Gilliland -
    - mattg@parallax.com
    - (916) 624-8333 x3018
    Ask me about the Lifetime Warranty on the Propeller BOE :smile:
  • edited May 2012 Posts: 0Vote Up0Vote Down
    I don't think this was said (although I have already echo'ed a couple things on this thread...), but it would seem to make sense to mount this on the StringRay's top plate so that the open sensor is facing the ground. Thought is to prevent any junk from flipping down and landing into and sitting on the sensor slot. I haven't check, but assume the wheel motor mounts are such that the shaft is centered? If so then the sensor should support being mounted on either the top or bottom plate.

    Matt - Given the specs you shared, there are some tight tolerances. Has there been any consideration regarding a dust cover? After rthe Expo LFO, I notice some junk that was picked up; little rocks etc.

    Matt Stemple
    www.StempleLABS.com
  • edited May 2012 Posts: 0Vote Up0Vote Down
    Stempile wrote: »
    I haven't check, but assume the wheel motor mounts are such that the shaft is centered?

    The motor on the StringRay is mounted so the output shaft is centered. The motor shaft is off center because of the gear box. Based on the pictures, looks like Matt is designing the sensor to be mounted on the bottom plate.

    On the top plate, the holes that line up with the motor and sensor are already used by the stand offs for the MSR-1 and Bread board plates. Looks like if I want to mount it with the open part of the sensor down I will be drilling my own holes... :thumb:

    Matt Stemple
    www.StempleLABS.com
  • edited May 2012 Posts: 0Vote Up0Vote Down
    I'm waiting before I do the StingRay thing now.........lol. I will not disasseble my Eddie to put new sensors on it either. I have never put anything together before that was as tough as those assemblys.....including the tires! Instead of opening a new topic a quick question on the Eddie encoders. The instructions were a little fuzzy on connecting them. I read that you were to pull a servo cable from one to the other and then hook the others servo cable, from the bottom pins, onto pin 11. But it shows in the schematic that pin 11, and pin 12, are the encoder pins. So do they connect seperatly or the way that the instructions have it. And yes I did remove the jumper to change addess between left and right.
  • edited May 2012 Posts: 0Vote Up0Vote Down
    Removing the roll pin in order to mount the codewheel may take a bit of work, especially if you don't have the right tools. Though roll pins aren't exactly rare, it might be a good idea, MattG, if Parallax could provide an extra set for some reasonable cost -- say a buck or two? Popping them out to retrofit an already built MADEusa or Eddie could deform/bend them. Would be ideal to hammer in a new pair, rather than try to re-use the old ones.

    -- Gordon
  • edited May 2012 Posts: 0Vote Up0Vote Down
    Would be ideal to hammer in a new pair, rather than try to re-use the old ones.

    -- Gordon

    Oh Gordon, where's your sense of adventure, economy and convenience? You're probably also a stickler for using new cotter pins on your front wheel bearing spindles EACH and EVERY time... :)
    Now why did it do that?
  • edited May 2012 Posts: 0Vote Up0Vote Down
    Nothing wrong with that. If it is worth doing it's worth doing right. At least that is what I was told when I was growing up.
  • edited May 2012 Posts: 0Vote Up0Vote Down
    it might be a good idea, MattG, if Parallax could provide an extra set
    Nah. We prefer to leave our long-time customers high-n-dry...tough luck :tongue:

    On second thought, Excellent idea. Although, the tough part I think is the removal of the pin in the first place - it's quite easy with the right sized pin-punch - but I have done it with the right sized, finish nail also. The real concern is to not damage the axle during the process...I have a method that works pretty well, maybe I should post pics?

    Shall consider how to implement within our sales order system (we wouldn't want to include in all new kits), but we'd like to give them free to existing customers that wish to change out their original Madeusa's and Eddie's...

    This is a Jim Carey thing to figure out (our sales manager)...he's never around though, a mythological creature of sorts...

    -MattG
    - Matt Gilliland -
    - mattg@parallax.com
    - (916) 624-8333 x3018
    Ask me about the Lifetime Warranty on the Propeller BOE :smile:
  • edited May 2012 Posts: 0Vote Up0Vote Down
    Hey smithdavidp -
    Not sure on this. Will take a look Monday, and get back to you...
    -MattG

    - Matt Gilliland -
    - mattg@parallax.com
    - (916) 624-8333 x3018
    Ask me about the Lifetime Warranty on the Propeller BOE :smile:
  • edited May 2012 Posts: 0Vote Up0Vote Down
    Thanks I appericiate that. Just received the shipping information for the notebook. It's comming from China??????? Anyway it is supposed to be here wednesday. After I trash everything and do a clean install I should be ready to Rock on.
  • edited May 2012 Posts: 0Vote Up0Vote Down
    I am the*lucky* recipient of the encoder kit for the Stingray and wanted to give a quick update. First off, I apologize for the delay as I had the encoders for about a week, but work has gotten in my way. The encoders installed very quickly, thanks to a little help from Matt as one of the mounts had several holes and the other only one set. My initial install put the emitter about a1/4 of an inch off center. It was just a matter of swapping one side to theother and things lined up perfectly. One other item worth noting is that one of my motors had the power lugs at about a 45 degree angle blocking the board from seating close to the motor. Again, with a quick call to Matt, he helped me"clock" the gearbox and again, alignlment is near perfect. I have included a picture to see the final installation. Total installation time was about 30 minutes. I should also point out that I swapped the old stingray board for the Eddie board, so getting a couple switches to wire a harness similar to that of Eddie added into my getting a little behind on actually testing the units.

    As of today, I am unable to use the encoders with the stock Eddie firmware, but have written a few small programs to just get a feel for how well they work. It basically consists a small amount of code making use of the Quadrature_Encoder.spin object. I am able to very easily acquire counts,approximately 240 per full rotation of the stingray stock wheel, direction and deltas. With now having a better understanding of their capabilities, my next step is to retro them into the Eddie firmware so that I can take advantage of Microsoft's RDS. Hope to have additional updates soon.

    Regards,

    John

    DSCN5960.jpg
    1024 x 768 - 83K
  • edited August 2012 Posts: 0Vote Up0Vote Down
    Hi,

    Is there a planning for this item, when will it be available for customers?

    Regards,
    Kris
  • edited August 2012 Posts: 0Vote Up0Vote Down
    Hmmmm Matt sure has taken a lot of mondays to answer my question but since the encoders work I'm happy. Besides that I know the secret behind installing the wires on the encoders now. lol
  • edited August 2012 Posts: 0Vote Up0Vote Down
    hey smithdavidp -
    Get back to you about what? huh? Who's on First? :-)

    so sorry. I was just informed how to "un- un-subscribe" to threads by our intrepid Mr. Savage...
    I'm up to speed now. :-)

    -MattG
    - Matt Gilliland -
    - mattg@parallax.com
    - (916) 624-8333 x3018
    Ask me about the Lifetime Warranty on the Propeller BOE :smile:
  • edited August 2012 Posts: 0Vote Up0Vote Down
    I don't care what anyone says......You're the greatest!!!! lol
  • edited August 2012 Posts: 0Vote Up0Vote Down
    Heyho everyone -

    So here's an update:

    First batch of Encoders are done (small, but mighty!)...

    The Encoders are going to packaged for each of the applications that it fits...

    The first one is for the MadeUSA / Eddie platforms. This is called the "Encoder set for MMWK". Two completes sets will be included in every MMWK. (Just like we have done it with the original "Position Controller")

    The second one is for the Stingray platform. This is called "Encoder set for Stingray", and same thing...two complete sets of boards, cables, encoder wheels, screws, etc.

    There's also a third option, and that is for all the existing (pre-new encoders) MMWK platforms that want to be upgraded to the new encoder, we'll have a different option...since it's very difficult (unless you have the right tool) to remove the drive pin on the axles (without damaging the axle itself), we've developed a cool, simple retro-fit method to remove the old encoder disk and replace it with a new one - all without removing the axle from the bearing block.

    Keep in mind what that the new Encoder's output is raw data - two sq.wave outputs - no intelligence on-board at all.

    Should be on-web this week/early next - they're goto kitting tomorrow :-)

    -MattG
    I don't care what anyone says......You're the greatest!!!! lol
    Ha!
    - Matt Gilliland -
    - mattg@parallax.com
    - (916) 624-8333 x3018
    Ask me about the Lifetime Warranty on the Propeller BOE :smile:
  • edited August 2012 Posts: 0Vote Up0Vote Down
    Looks like if I want to mount it with the open part of the sensor down I will be drilling my own holes...
    Right you are Stempile -

    Part of that reasoning is because a few of us here really like the Stingray platform, and would like to see more accessories (but that'll depend upon demand). One of the thoughts a while back was to make a taller set of side plates allowing for a taller "belly" inside the machine. This would allow for a top plate add-on that could span or go out over the wheels, among other things...

    By mounting the encoder on the bottom plate, the elevation motor to the encoder stand mount is fixed, regardless of what we do in the future.

    -Matt
    - Matt Gilliland -
    - mattg@parallax.com
    - (916) 624-8333 x3018
    Ask me about the Lifetime Warranty on the Propeller BOE :smile:
  • edited August 2012 Posts: 0Vote Up0Vote Down
    Is there a planning for this item, when will it be available for customers?
    End of this week, early next. Now if I can just find my "act" and get it together...
    -MattG
    - Matt Gilliland -
    - mattg@parallax.com
    - (916) 624-8333 x3018
    Ask me about the Lifetime Warranty on the Propeller BOE :smile:
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