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Feetech Chassis on Amazon — Parallax Forums

Feetech Chassis on Amazon

ercoerco Posts: 20,244
The two chassis I got direct from China are now available on Amazon. $15 gets your choice of beautiful aluminum chassis kit with two DC motors PLUS the coveted motor controller board which drives two motors using servo-style pulses. Essentially converts DC motors into CR servos. Mikey Likey. Mine are red, these are blue. I'll have to get blue ones too, I guess.

blue rectangular https://www.amazon.com/gp/product/B06XZC2XDV uses gutted 9g servo-style gearmotors, works fine. Heavy-duty caster seems out of place but works.

blue round https://www.amazon.com/Feetech-FT-DC-006-SMC-Aluminum-Vehicle-FT-SMC-2CH/dp/B06XXS8L1C uses Solarboticsstyle gearmotors in several different gear ratios, 48:1, 120:1 or 256:1 but the description doesn't say which. I favor the 120's myself.

There are a few Feetech offerings on Amazon as well, they look similar. There's a red round with no controller for $15 and a yellow rectangular with low-grade FS90R CR servos, I'd stay clear of those.



Comments

  • How do those motors work erco? They look like the low torque, speed demons I have on other critters.

    @
  • ercoerco Posts: 20,244
    On the round robot? They all look alike, even with different internal gear ratios. I know exactly the too-fast types you mean, most are 48:1 and very squirrely. AsI mentioned in the OP, I much prefer 120:1 or 256:1 types.
  • ercoerco Posts: 20,244
    Prices increased from $15 each to $20/square and $18/round since I posted.

    Apparently I'm manipulating the world of robot high dollar finance.
  • Not surprised by the price increases. This brings them closer to Adafruit, and helps them absorb the high failure rates of those motors.

    They really are crappy motors, in case you didn't know!
  • WhitWhit Posts: 4,191
    I saw that too. Should have ordered at $15! But my hands are pretty full and project back-up is increasing...

    Guess I'll just keep watching...
  • ercoerco Posts: 20,244
    Whit wrote: »
    I saw that too. Should have ordered at $15! But my hands are pretty full and project back-up is increasing...

    Guess I'll just keep watching...

    The watching is over! Price on blue round dropped to $12.50 so I nabbed one with free ship thru Amazon Prime. Supposedly includes the 120:1 motors, we shall see.

    https://www.amazon.com/gp/product/B06XXS8L1C
  • ercoerco Posts: 20,244
    The rectangular chassis dropped to $15 but I'd stay clear. Motor quality is spotty and that curiously heavy industrial caster just gets in the way.

    https://www.amazon.com/Feetech-FT-MC-002-SMC-Aluminum-Vehicle-FT-SMC-2CH/dp/B06XZC2XDV
  • ercoerco Posts: 20,244
    Good news: fast ship, got my round blue chassis today. It's nice.
    Bad news: It comes with 48:1 motors, not the 120:1 claimed
    Med news: At least the included controller does a pretty decent job controlling the motors at low speed. Video soon.
  • I thought it was a good deal for the chassis alone. It makes a nice AWD robot.

    I wonder if these would work well on it with some nice servos. Thoughts?

    https://www.amazon.com/UniHobby-UH143-Aluminum-Compatible-Universal/dp/B01EDKQERU

  • erco wrote: »
    Good news: fast ship, got my round blue chassis today. It's nice.

    A few months back someone gave me one of these, though it was red. Can't remember the guy's name, though. Tall fella with a scraggly beard.

    The "gutted" servo worked pretty well. I just don't trust those yellow WowWee-ripoff motors, from any source.
  • ercoerco Posts: 20,244
    A few months back someone gave me one of these, though it was red. Can't remember the guy's name, though. Tall fella with a scraggly beard.

    The "gutted" servo worked pretty well. I just don't trust those yellow WowWee-ripoff motors, from any source.

    Really? You mentioned bad motors before, I thought you were talking about the blue gutted 9g servos. I've had some bad ones, but all the yellow Vigor/Solarbotics/WowWee motors have been good.

    xanadu wrote: »
    I thought it was a good deal for the chassis alone. It makes a nice AWD robot.

    I wonder if these would work well on it with some nice servos. Thoughts?

    https://www.amazon.com/UniHobby-UH143-Aluminum-Compatible-Universal/dp/B01EDKQERU

    Re: AWD You mean the rectangular chassis? Probably much better 4WD than 2WD, that heavy caster is ridiculous.

    Mecanums are cool but pricey. Duane and I like the green VEX mecanums (good price), which I can't find online right now (should I have hoarded those?). Second video.

    Feetech chassis review:


    My Vex Mecanum bot:

  • erco wrote: »
    Really? You mentioned bad motors before, I thought you were talking about the blue gutted 9g servos. I've had some bad ones, but all the yellow Vigor/Solarbotics/WowWee motors have been good.

    I only have experience with two of the gutted Feetech motors, from the base you so kindly gave me. Those were good, but I admit that two aren't enough of a sample.

    The yellow motors (i.e. fake WowWee) are hit-and-miss. As you note, you never really know if you're going to get the 1:48 motors, which are not only a bit lame for robots, but with the low torque pretty much guarantees the robot won't travel a straight line.

    I've gotten some for testing that simply stopped after running a few seconds. Munchings and crunchings from inside the gearbox.

    The white Solarbotics motors are not the same as the cheap yellow ones that are coming everywhere from China. Theirs are a higher quality, and I believe from the same factory that supplied/supplies WowWee. I don't know what factory(ies) make the yellow motors. They appear to be very widely distributed, where anyone can buy a bunch and sell their Very Own Robot.

  • ercoerco Posts: 20,244
    Those 48:1 are much better with smaller wheels, such as https://www.ebay.com/itm/2WD-Smart-Car-Tracking-Robot-Car-Chassis-DIY-Kit-Reduction-Motor-Set-For-Arduino/172854089141

    But the big fat tires they usually come with are just plain bad. https://www.ebay.com/itm/Smart-Car-Chassis-Tracing-Car-Robot-Chassis-with-Speed-Encoder-Kit-for-Arduino/182856281675?hash=item2a93156e4b:g:D-kAAOSwr6pZ8VvM

    (And dig those optical encoder disks of clear plexiglas... shown with the protective paper still on... :):):) )
  • Pretty amazing what you can get for four bucks these days! With free shipping, those motors must cost about 25 cents each. Solarbotics sells the white gear motors for over $5 *each*.
  • ercoerco Posts: 20,244
    Pretty amazing what you can get for four bucks these days! With free shipping, those motors must cost about 25 cents each. Solarbotics sells the white gear motors for over $5 *each*.

    My thoughts exactly!
    http://forums.parallax.com/discussion/comment/1429941/#Comment_1429941
  • These Chinese-made products with free shipping (specifically those on eBay) are made possible by two very "bad deals" which converged. Specifically, the USPS subsidy of inbound Chinese goods which started in the 80s and the Chinese-subsidized shipping from manufacturer to the handoff is loading the USA with small packages. And if it's under 5 oz, we get it shipped for free.

    Read more here https://www.forbes.com/sites/wadeshepard/2017/11/05/how-the-usps-epacket-gives-postal-subsidies-to-chinese-e-commerce-merchants-to-ship-to-the-usa-cheap/#2416534f40ca

    The taxpayer is subsidizing this habit. I benefit from it too, but as time passes I'm far more reluctant to get that "free shipping" bonus.

    Ken Gracey
  • I suspect a relatively small portion of the population buys these Chinese deals via eBay, Amazon, or especially Alibaba. Erco's purchases skew the ratios. I don't know anyone quite as avid as Erco.

    Shipping times can be one or two months' long, and because it's so expensive to return defective merchandise, buyers who get a bad part just eat it. I guess the savings make the risk more palatable. For my work I can't rely on the unreliable supply chain -- I write about some kit and three months later it's gone, or changed.

    Some time back I renounced hoarding, and I no longer stockpile (in fact a few years ago I gave both Erco and Xanadu bins full of my electronics parts). Just today I ordered some stuff from a few online outfits, and it was everything I need for next month's projects. I don't plan beyond that.
  • Ken GraceyKen Gracey Posts: 7,386
    edited 2018-01-24 19:25
    Well, the estimates of the "free shipping" costs to the USPS are really significant. They're very secretive about their financials, but this is costing us somewhere between $100M and $5B a year. You can buy a TOILET BOWL brush from eBay for $2.14 from Shenzhen, CN with free shipping. Even Wal-Mart (who wouldn't be an ePacket beneficiary) gets screwed in this deal because their cheapest TOILET BOWL brush is around $3.50.

    I don't think the free shipping fiasco is a benefit to the Chinese suppliers, either. Between their lack of IP protection, how would anybody even figure out who makes the "original" HRS-04 $1.00 Ultrasonic Sensor? You can't - it's probably made by 100 factories! The consumer just picks the cheapest cost, with free shipping, and this double-whammy simply drives the margins down for Chinese suppliers. I bet they're making about 5 cents on an HRS-04 Ultrasonic Sensor.

    Further, take a look at this listing:

    https://www.ebay.com/itm/HC-SR04-Sound-Ultrasonic-Wave-Detector-Range-Distance-Sensor-Module-For-Arduino/122185875749?epid=506545892&hash=item1c72d88125:g:7CcAAOSwPCVYBLj3

    And look at the messed-up looking product in their main image. The pins are bent in their main marketing photograph!

    HRS-04.jpg

    Free shipping is bad because:

    - it promotes hoarding
    - it requires a subsidy from the USPS which is a real bad deal
    - requires you to buy lots of extras and throw away the failed units, filling our landfills
    - promotes copycats and a "race to the bottom"

    While I'd love to dig into this much deeper, it's not to the benefit of Parallax for me to spend much time on it. I might spend a few minutes writing a letter to a senator or congressional member.

    Ken Gracey
    800 x 800 - 56K
  • Ken GraceyKen Gracey Posts: 7,386
    edited 2018-01-24 22:00
    As I proceed to be the ultimate thread hijacker I'm sharing my final roundup on the ePacket rate with a letter to my congressman. Sorry erco - I expect that my message will be entirely ineffective and we should likely enjoy the freedom of free shipping for the rest of our lives! - Ken Gracey

    Screen%20Shot%202018-01-24%20at%201.56.58%20PM.png
  • thanks, @ParallaxKen

    Mike
  • Ken, the letter looks good to me. It might even serve as a good template for other small manufacturers facing the same issue. Cheap robot parts or not (who doesn't love to save money!), this type of knee-capping undercutting does nothing for innovation.

    As a reminder, we're not limited to just writing to only our local representative. I'm pretty sure customs and trade issues are handled by the House Ways and Means subcommitte on trade. Looking it up, Dave Reichert is the current chairman. He's not running for reelection in 2018, so maybe he'd be more willing than otherwise to shake some things up. The same letter could go to all the names listed here:

    https://en.wikipedia.org/wiki/United_States_House_Ways_and_Means_Subcommittee_on_Trade
  • ercoerco Posts: 20,244
    edited 2018-01-25 01:29
    Very well said, Ken. Any movement starts with one person, then a trickle, then a roar.

    I better hoard those toilet brushes before your letter awakens the sleeping giant and free shipping is no more!
  • One of the reasons I believe many robot builders don't do the eBay China thing: US resellers like Adafruit import these same kits from Chinese factories. Prices are higher, as expected -- they provide customer service, often add value in the form of documentation or libraties, assume the risk of defective merchandise, and so on. I wonder if they'd carry these kits and parts if people didn't chose them over their eBay counterparts.

  • As a reminder, we're not limited to just writing to only our local representative. I'm pretty sure customs and trade issues are handled by the House Ways and Means subcommitte on trade. Looking it up, Dave Reichert is the current chairman. He's not running for reelection in 2018, so maybe he'd be more willing than otherwise to shake some things up. The same letter could go to all the names listed here:

    https://en.wikipedia.org/wiki/United_States_House_Ways_and_Means_Subcommittee_on_Trade

    I knew there were more opportunities to influence but I didn't know who to contact. Count on these people also getting a letter. Thanks for the additional ideas, Gordon!

    Sometimes the simple act of writing relieves one's mind from the situation, doesn't it? I feel a lot better after putting my thoughts in a letter and doing what we're supposed to do, even though it has no effect.

    Ken Gracey

  • Ken GraceyKen Gracey Posts: 7,386
    edited 2018-01-25 03:07
    erco wrote: »
    Very well said, Ken. Any movement starts with one person, then a trickle, then a roar.

    I better hoard those toilet brushes before your letter awakens the sleeping giant and free shipping is no more!

    I'll make you a deal, erco. This deal is better than another free shipping ePacket from China, better than HRS-04s that work - and it requires an open-minded person as yourself.

    I'd like you to take a photo of your electronics storage area. It might be a whole bay in your garage, or the entire closet of your robot museum. I'd like you to share that photo on the forums so we can all see the success ratios required to properly source these low-cost goods from China. We know that the good parts make it into your robots, but but about the epic fails? What's the ratio of good to bad? We need a photo!

    In exchange, I offer you any American-made product from Parallax valued up to $150. Let's call it "Chef's Choice" and you'll be the chef.

    Virtual handshake?

    Ken Gracey

    P.S. If you accept, I'll also order us each three (3) of the $2.17 toilet bowl brushes to see what they're all about. If nothing else, they'll symbolize washing away the dirty stuff that made free shipping possible.

  • ercoerco Posts: 20,244
    edited 2018-01-25 03:46
    Back OT: gear ratio comparison. My cat found it interesting, anyway.

  • I prefer the round Feetech chassis models over the rectangle ones.
  • ercoerco Posts: 20,244
    Ken Gracey wrote: »
    I prefer the round Feetech chassis models over the rectangle ones.

    +1

    WRT my parts stores, it will be many pics, as they are tucked away in various places. Closets, bins, boxes, racks, in the house and garage! Mixed in with toys, gears, plastic, glue, and various building materials.

    I envied Duane Degn a few years ago when he posted his dedicated stack of neatly organized and labeled bins. THAT'S the more photo-friendly storage solution!

  • Erco's hoarding is special, and a stuffed parts bin is allowed.

    He makes his living as a consulting toy designer, and he needs ready access to lots of clever bits and pieces as he creates a new design. My understanding of his process is that he uses these parts for working prototypes, but those parts may and probably won't be used in any final product.

    It's guys like me who (used to) collect stuff just to have it and never use it. Part of my problem was Industrial Liquidators. Erco knows what I mean, since he had one around the corner from his house as well...
  • ercoerco Posts: 20,244
    edited 2018-01-25 18:29
    Oops, I did it again. The erco effect lives on. As soon as I say buy something (and say even more this time), the item disappears.

    In this case, I emailed Amazon that the blue robot came with 48:1 motors (not the 120:1 types the seller claimed in his reply to my question) and POOF, the item is gone: https://www.amazon.com/gp/product/B06XXS8L1C

    In the Nissan Leaf forum, I recommended a conspicuous value in a home L2 (240VAC) charger (EVSE) at $214. The day after I posted, the price jumped to over $300.

    Guess I can add "Internet influencer" to my resume. Either that or "ruiner of all the fun".
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