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Parallax's New Wheel Kit--What could it mean? — Parallax Forums

Parallax's New Wheel Kit--What could it mean?

VaatiVaati Posts: 712
edited 2009-09-18 03:42 in Robotics
Hello everyone, I just saw the new wheel kit that was released, and those wheels look VERY much like the ones of this...· Does this mean that a new bot is coming along...?· If so, then it will most definitely be expensive, as those wheels alone are $100...

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Comments

  • Tom CTom C Posts: 461
    edited 2009-09-12 17:17
    Vatti,

    Quality products, such as what Parallax offers, do not come cheap. In the world of robots you generally get what you pay for. Be patient and save your money. A good quality robot is better than a bunch of cheap ones that you are always having to repair.

    Regards,
    TCIII

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    If you are going to send·a Robot·to save the world, you·better make sure it likes it the way it is!
  • Ken GraceyKen Gracey Posts: 7,392
    edited 2009-09-12 18:38
    Hey guys,

    Similar to the Motor Mount and Wheel Kit, this is a real top-quality product made in our Rocklin office on our Haas CNC machines. No expense is spared when it comes to our robotic hardware - we want people to have hardware that works well and holds up. The aluminum is machined, tumbled, anodized and packed to prevent scratching.

    As far as the expense for this specific product, here's a little business lesson that would be appreciated by anybody who manufactures and sells products:

    Labor cost 3.48620
    Material cost 31.84318
    Fixed overhead 6.97130
    Variable overhead 0.00000
    Sub contract cost 0.00000
    Total cost 42.30068

    This is our cost of manufacturing (parts, material, screws, wheels, motors), including manufacturing labor (the cost of the CNC operator's labor, per unit). This excludes overhead required to support the product, such as salaries in marketing, editorial review, technical support, engineering (these numbers do not include the engineering NRE, which could be $10-20K). At initial glance, you'd think "wow! Parallax makes $58/unit on those kits!". But, in reality, it's among the lowest margin any sensible company would accept for what is considered a low-volume product. The return on investment is probably around 500 units.

    My point (and I realize nobody is complaining) is that $99 is a real deal for such a kit. In the end products like this barely support a USA machine shop. Our machining services aren't designed to make money on their own, but to supplement and inspire other purchases in motor controllers, sensors, microcontrollers, educational books, etc.

    I promise that you'll be happy with any machined product from Parallax. We absolutely refuse to make low quality stuff at the benefit of a profit, and we'll use expensive manufacturing processes to deliver some really nice designs. If we were about profit, this motor mounts would be made from sheet metal, punched and then shaped on a brake.

    BTW, this kit also fits with our 28971, Caster Wheel. They're both designed to mount under your robot base. Give this kit a try and return it if you are not more impressed than you expected to be. We'll take care of your desires to be happy with our products no matter what they are, I promise.

    Ken Gracey
    Parallax Inc.
  • VaatiVaati Posts: 712
    edited 2009-09-12 18:55
    Oh no, I was not complaining about the quality or price of ANY Parallax product, I was just noting on how the price of the robot-to-be may be affected by this excellent wheel kit.

    I think the point of this thread was greatly misinterpreted. I only meant to ask whether anyone knows whether there are any updates on the robot talked about in the thread I linked, and whether this kit could be the same wheels used in the "stingray"...

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    Quit buying all those fixed voltage regulators, and·get an Adjustable Power Supply·for your projects!· Includes an LED testing terminal!

    *-NEW-* SD Card Adapter·Now available!· Add extra memory to your next Propeller project with ease!
  • P!-RoP!-Ro Posts: 1,189
    edited 2009-09-12 19:40
    Looks like it. With 100 dollar wheels I predict the stingray will be $400.

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    PG
  • Ken GraceyKen Gracey Posts: 7,392
    edited 2009-09-12 21:19
    @Vaati, I didn't think you were complaining by any means (though complaints are welcome). I just saw the opportunity to explain why some of these products are quite expensive.

    But back to your question and the reason for your post, which I didn't answer. This product is using Stingray motors and wheels. The motor mounts are not used on the Stingray, however.

    Stingray will be out in a few weeks at this point, at less than $300.

    - Ken
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2009-09-12 22:06
    Ken,

    Since you're stating zero for subcontract cost, does that imply that you do your own tumbling and anodizing, too? Or am I misunderstanding something in your post?

    -Phil
  • Ken GraceyKen Gracey Posts: 7,392
    edited 2009-09-13 04:53
    Hey Phil,

    Yes on the tumbling. We added that capability in the summer.

    You're right about the anodizing costs - they should show up under "subcontract". I'll have to look into that a bit, but it's additional costs for which we have not properly accounted.

    - Ken
  • TimmooreTimmoore Posts: 1,031
    edited 2009-09-13 07:27
    Ken, A question about the motors. Looking at the 3d model the motor has a 2mm shaft out the back for an encoder. Also looking at the model it looks like a usdigital E4P, for 2mm shaft, with hole in cover and transfer adhesive would work. e.g a E4P-120-079-D-H-T-B. Have you tried a USdigital encoder or another encoder with this motor?
  • WhitWhit Posts: 4,191
    edited 2009-09-13 12:22
    Ken Gracey (Parallax) said...

    Stingray will be out in a few weeks at this point, at less than $300.
    Ken,

    I can hardly wait... ·I will start saving now! This is the only reason I haven't ordered the new motor and wheel set. I want on of the Stingrays. I am glad they will work with the caster wheel too - Is that what the final stingray will use or will it be as previously pictured (i.e., with the omi-directional wheel)?

    Thanks for asking about this Vaati and thanks Ken for letting us know what goes in to making these.

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    Whit+


    "We keep moving forward, opening new doors, and doing new things, because we're curious and curiosity keeps leading us down new paths." - Walt Disney
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2009-09-14 02:01
    Timmoore,

    We do not carry the encoders, but we have tested them to work with these motors. The ones with the sticky back can be tricky though to get good alignment since the motors have text on the plastic which can throw alignment off a bit. You just need to make sure it is even and you should be good to go. Later after the initial release we will visit the encoders and most likely create some sort of AppNote and object for dealing with them. Take care.

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    Chris Savage

    Parallax Engineering
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  • TimmooreTimmoore Posts: 1,031
    edited 2009-09-14 02:58
    Thanks, I have used the e4p encoders before both screw and the sticky back ones and know the fun aligning them up correctly. I was a bit worried about the bump around the shaft and how that fitted round the encoder but didn't want to take the bot I have apart that uses them.
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2009-09-14 16:15
    The ones I have (which I believe are the same model) fit around the shaft hub just fine. The raised text in the plastic was the main inhibitor. But they do work if you get them on there correctly. I also remember having to carefully bend the motor wire terminals outward a bit. As soon as I get the chance these will be replaced and I will take some pictures and post them. Take care.

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    Chris Savage

    Parallax Engineering
    50 72 6F 6A 65 63 74 20 53 69 74 65
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  • TimmooreTimmoore Posts: 1,031
    edited 2009-09-14 16:19
    Sounds the same as this http://www.lynxmotion.com/images/html/build095.htm
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2009-09-14 16:30
    The motors appear to be the same size and are made by the same manufacturer. So yes, the installation would be the same. Take care.

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    Chris Savage

    Parallax Engineering
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  • SandgroperSandgroper Posts: 62
    edited 2009-09-16 14:37
    Please forgive me if I'm getting a little off-post here, but I was wondering if anyone has been caught out - like me - by the digital encoders being mounted on the rear shaft of the motor.

    What tripped me up is that the rear shaft doesn't turn at the same speed as the output shaft. The encoders I have give 100 cpr. In my case, the 30 x gearing of the motors I'm using equates to 3000 counts per revolution. This goes up to 12,000 counts at full quadrature. No wonder my distance routines weren't working! eyes.gif

    You might rightly think "well DUH!", but the effect of the higher speed of the rear shaft isn't mentioned in any sales literature for the encoders or the motors.

    Other than that, the stick-on encoders work well and I'm quite happy with the increased resolution!
  • WhitWhit Posts: 4,191
    edited 2009-09-17 16:38
    Hey all,

    The 7.2V Motor, Bracket and Wheel Kit is now &79.99! What a deal! See Ken's post above.

    See - http://www.parallax.com/Store/Robots/AllRobots/tabid/755/ProductID/587/List/0/Default.aspx?SortField=ProductName,ProductName

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    Whit+


    "We keep moving forward, opening new doors, and doing new things, because we're curious and curiosity keeps leading us down new paths." - Walt Disney
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2009-09-18 03:42
    Since the motors are gear motors the fact that the motor shaft and the output shaft are at different speeds in inherent to the design of the motor. Usually the motor will have a gear ratio on it. The shaft could be used for an encoder, but certainly not the one discussed due to lack of room for the encoder wheel and the design wasn’t meant to fir the output shaft. With a Propeller the high speed counts should not be a problem. Take care.

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    Chris Savage

    Parallax Engineering
    50 72 6F 6A 65 63 74 20 53 69 74 65
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