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Parallax's 12V Modular Wheel and Motor Mounts - Feedback Requested! - Page 4 — Parallax Forums

Parallax's 12V Modular Wheel and Motor Mounts - Feedback Requested!

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  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2007-08-09 16:29
    Actually Whit edited his message while I was writing mine.· He didn’t originally have that there so I didn’t see it.· It is simple and could work nicely.· I would have to try it.
    ·
    As for the charging attachment I have seen a few variations but they all work the same.· The robot hones in on a beacon, and once lined up, two contactor plates on the charging station make contact with two antennas which connect to the power source to initiate charging.· Usually a height is chosen which won’t interfere with typical objects or the sensors.
    ·
    Yeah Whit, your idea is much simpler than using a strain gauge.· The main differences would be that with your switch you know if the flag has been hit or not.· With a strain gauge you can tell how hard it is being pressed against.· Under ideal circumstances this could be used to guess the height of the object your bumping into, but we won’t get into that.· =)

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    Chris Savage
    Parallax Tech Support


    Post Edited (Chris Savage (Parallax)) : 8/9/2007 4:39:52 PM GMT
  • ZootZoot Posts: 2,227
    edited 2007-08-09 19:34
    Here is a good discussion of self-charging: www.schursastrophotography.com/robotics/docking2.html. We are working on a self-charging (via beacon) system for a big 'bot here -- we are not using Mr. Schur's electronics, but are using his great idea of metal balls on top of springs for the charging contacts.

    For beacon location, we are using two IR sensors separated by a long matte black divider -- this gives a very narrow angle when the beacon strikes both sensors (i.e., the dock is straight ahead), and very broad angles when beacon is only one side or the other (so you can find it to begin with). At close range, the two Ping))) eyeballs on the 'bot help with distance to the charger for "locking on".

    These motors are so great -- so quiet. Can't wait till they are for sale (don't forget assurances earlier in this thread re: encoder availability).

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  • WhitWhit Posts: 4,191
    edited 2007-08-09 20:22
    Zoot,

    Great link - thanks - lots of good info there to study.

    Chris,

    I was also thinking that the ring around the tail (flag pole) could have individual segments broken by an insulator. That could help you determine which way to back up (though you could just go opposite of the way the motors were previously heading).

    Thanks for not getting into how the strain gauge could tell how high the object was that you hit - it would probably give me a headache...smilewinkgrin.gif

    But now that you've mentioned it, I will probably have to at least try to figure out how it works. The longer the distance the less·bending stress (moment)·in the pole I guess? And with a little experimentation, you could get a pretty good estimate. Am I even close?

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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

    Post Edited (Whit) : 8/10/2007 1:07:35 AM GMT
  • D FaustD Faust Posts: 608
    edited 2007-08-09 21:46
    Whit that would be correct. In order to figure it out though you would have to see how far the bot travels after the pole hits.

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  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2007-08-09 22:02
    Whit,

    Yes, you are correct in those assumptions…Typically you’re not going to have a lot of items in a given environment that are a lot of different heights. It will be like Desks/Tables and Chairs. Given that you can guess which you are under based on the amount of stress.

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    Chris Savage
    Parallax Tech Support
  • StampNut2StampNut2 Posts: 224
    edited 2007-08-11 03:23
    I agree with whit, If you make it I will be pleased with it, The only problem I have with this product is freight, At 3-4lb I hate to think what the freight to New Zealand would be. I love Parallax products, but freight is a killer for me. Any idea how much it would cost to send to NZ?

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    Never give up when things go wrong.

    Post Edited (StampNut2) : 8/11/2007 3:35:49 AM GMT
  • Capt. QuirkCapt. Quirk Posts: 872
    edited 2007-08-12 22:09
    This is a prototype. For production we would use a roll pin which does not protrude beyond the diameter provided by the back of the wheel. There would be no way to catch your finger on the roll pin.
    Ken,

    I wasn't really thinking about that so much (that just falls under the catagory of what you want people to see and what you don't want them to see)

    <<=== Bill the quirk

    The more important point was the sacrificial lamb. So long as everything remains light duty there isn't a problem, but as you reinforce the product·and you increase the load (the axle with the second bearing and use a positive drive system) it tends to make something else break instead.



    Although, LOL, this is most likely more useless info for a man that has engineers and marketers at his "beck in call"
    hence the name, "Quirkus Maximus"
  • WhitWhit Posts: 4,191
    edited 2007-08-15 13:15
    StampNut2 said...
    I hate to think what the freight to New Zealand would be. I love Parallax products, but freight is a killer for me.
    Freight fright! Sounds like you need to become the New Zealand Parallax distributer/seller!

    Before I started my robotics, I lived in the San Francisco Bay area (about an hour and half from Parallax and in the middle of all sorts of Robotics goodies). Now, I am back home·in Louisiana. I could kick myself. We do have good seafood though.

    Oh well! Somebody has to build all the robots in New Zealand and Louisiana.

    Chris said...
    I hope to have the sensors mounted before the weekend and some video from the same room with obstacle avoidance in place. Enjoy!

    Waiting patiently (or at least trying).

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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

    Post Edited (Whit) : 8/15/2007 1:22:37 PM GMT
  • D FaustD Faust Posts: 608
    edited 2007-08-15 15:51
    Try New England.· You can't get much farther in the Continental US.

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  • WhitWhit Posts: 4,191
    edited 2007-08-16 11:28
    Hey Chris,

    I was out at Home Depot yesterday and was looking at the raw materials to make a chassis like the one you've built. They had everything. smilewinkgrin.gif

    I did see something else that was really neat. I did not know that you could buy these off the shelf. They were endcaps for the open ends of metal tubing. I did a quick search on the web and found these - http://www.stockcap.com/styles/plugs/index.asp·(see picture below)

    This might help finish out the chassis nicely. You could even mount something in or to them.


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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

    Post Edited (Whit) : 8/16/2007 11:37:01 AM GMT
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2007-08-16 14:41
    Whit,

    ·· Very nice! I can’t believe I didn’t think of that! Then again, I didn’t purchase the metal. Working on two other projects I didn’t quite get everything done that I had planned, however, I did get some of the sensors mounted as shown in the pictures below. Problem right now is the first set of IR sensors is way too sensitive. So once I get those tuned I will install the other set. The PING))) sensors on the mounting brackets work great though! When the guys go for the next parts run to Lowes I’ll have them get those end caps and the flag. Hopefully we’ll have some video Monday. Take care.

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    Chris Savage
    Parallax Tech Support
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    1044 x 781 - 141K
  • D FaustD Faust Posts: 608
    edited 2007-08-16 17:05
    I like the small ir setups on the corners.· What is going to be the primary navigation sensor, IR or PING?

    If you are using IR, you might want to keep the IR detector at a 45 deg angle and have two IR leds on each board, one facing forward and one to the side.· You would get 4 different directional feed backs with two detectors.(Not that you need to save on parts)· It would save you I/Os.

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  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2007-08-16 17:28
    D Faust,

    The IR Sensors on the corners are facing exactly 45 degrees. There is no primary sensor…The PING))) could be considered it on hand, but then it would miss lower things that may hit the wheels. The IR is there mainly to protect the wheels. Take care.

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    Chris Savage
    Parallax Tech Support
  • D FaustD Faust Posts: 608
    edited 2007-08-16 17:33
    OK I get it. So the IR is just there to prevent wheel obstruction, and the ping is used for navigation. Thanks

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  • WhitWhit Posts: 4,191
    edited 2007-08-16 21:27
    Chris,

    It's really looking great. Nice to see the BOE running on the same battery too!

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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
  • StampNut2StampNut2 Posts: 224
    edited 2007-08-18 21:32
    Whit, Freight fright! Sounds like you need to become the New Zealand Parallax distributer/seller! Now that sounds like a good idea, We do have an agent in NZ but they stock next to nothing and is a waste of time, Also their mark up is ridicules. I wonder what it would take to become an agent.?????

    Just as a matter of interest Ken, I have built a very similar robot to you only on a smaller scale robosapienv2-4mem8.page.tl/ Follow Generic robotic base tutorial,

    I'm getting keener all the time on your project Ken and may even rip apart my Generic base for the HB 25 controllers and prof Dev board. Can't wait for more info.

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  • WhitWhit Posts: 4,191
    edited 2007-08-23 00:14
    Hey Chris,

    Any news?

    I have been thinking about what I might do. Using a frame like yours, I might shape the top something like the attached picture. This would make a space for the wheels, give the platform some shape·and give·the wheels·a little protection. It might also let them slide past something soft too. I do like the black you used. What is the material? It looks good with the aluminum wheels and frame. It needs a Parallax sticker though! ;-) And maybe that cool new uOLED display somewhere.

    undefinedattachment.php?attachmentid=48833

    Can the battery lie on its side? Is that o.k. with that sort of battery?


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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

    Post Edited (Whit) : 8/24/2007 5:20:06 AM GMT
    280 x 252 - 7K
  • StampNut2StampNut2 Posts: 224
    edited 2007-08-23 12:03
    Whit, That new uOLED is some piece of work, That would look great on the platform.

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  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2007-08-23 14:46
    Whit,

    Ken also would like to see a more ‘rounded’ unit. I suppose if one is made it will have similar attributes. Your mention of the uOLED reminded me of the conversation we were having in tech Support about a possible use, originally shown in I believe Servo magazine. They had a robot with a TV monitor which showed someone’s face and it could appear to change emotions. You could download (using a Micro-SD Card) face images and send commands to switch between these images, giving the impression of emotions for your robot. Picture this…Your robot is heading forward and is about to hit a wall and makes a face of fright! =) As for the batteries…I don’t know. They are sealed, but I have never tried to do that so I would not be the best person to answer. Perhaps someone more knowledgeable?

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    Chris Savage
    Parallax Tech Support
  • DufferDuffer Posts: 374
    edited 2007-08-23 19:33
    Or you could use one of the uOLEDs like I did on my "Radar" Bot. It looks like you've got plenty of "deck" space and enough power available.

    http://www.youtube.com/watch?v=yfxgegKY-80

    You could just add another BS2/BOE, let it run the PING))) sensors and the display·(I only used the top half of the display to show a 180 degree sweep in front of my bot, the bottom half could be used to display the view from rear PING))) sensor),·put a wireless video camera on the bot that "looks" at the screen and transmits the image back to a "base station". Wireless transceivers (or the R/C setup you already have)·on the bot and the base station give you complete control even when you can't see the bot. This setup works great in the dark.·I was able to navigate an obstacle course in my garage with the lights off, from the kitchen for about 40 minutes ('till the batteries ran down). Pan/Tilt on the camera also allows remote viewing and control when not looking at the display. The Stamp controlling the PING))) sensor(s) and the display could send simple distance (to closest object) and direction to the primary Stamp doing the "driving" if you eventually wanted to go autonomous .

    Steve




    Post Edited (Duffer) : 8/23/2007 7:37:57 PM GMT
  • WhitWhit Posts: 4,191
    edited 2007-08-23 22:29
    Chris Savage (Parallax) said...
    Whit,

    Your mention of the uOLED reminded me of the conversation we were having in tech Support about a possible use, originally shown in I believe Servo magazine. They had a robot with a TV monitor which showed someone’s face and it could appear to change emotions. You could download (using a Micro-SD Card) face images and send commands to switch between these images, giving the impression of emotions for your robot. Picture this…Your robot is heading forward and is about to hit a wall and makes a face of fright! =)
    Chris,

    That is what I was thinking! It sure would be neat, wouldn't it?·I was watching i Robot the other day. Sonny's face is sort of·display screen·looking. In the future I can imagine a face shaped display. Sure would give a robot some personality.

    Duffer said...
    Or you could use one of the uOLEDs like I did on my "Radar" Bot.


    Duffer,

    I remember when you posted this originally. It was a great project. I love how you used the display on board. You could also display something like your avitar for a very·spooky effect!

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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
  • DufferDuffer Posts: 374
    edited 2007-08-24 02:03
    Be careful Whit or I'll put the animated version back up. It blinks at you every 2 seconds. It creeped some people out and they asked me to take it down. ;-D
    Steve
  • StampNut2StampNut2 Posts: 224
    edited 2007-08-24 07:20
    This discussion is getting very interesting guys, Keep the ideas coming.

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  • WhitWhit Posts: 4,191
    edited 2007-08-26 18:32
    StampNut2,

    I can't help myself. I am so excited about this new platform size. The new motors and wheels will make this step up in size a great logical next step after the BOE Bot. The bigger platform will give so much room and capacity to try new things. I love the new hybrid and the hydraulic robot that Parallax is developing - but this kind of robot is more in line for me cost and ability wise. It is also quiet and appears to be strong.

    Like so much of what is on the forum - it is fun to get new ideas and try new things. Thanks for egging us on!

    And by the way Duffer, I remember the blinking verson!

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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
  • Wade SmithWade Smith Posts: 25
    edited 2007-08-26 22:38
    Let's see, Ken Gracey posted:

    Back to the question. How about by the end of August? I think we can make that date without a problem.

    That is this coming Friday, so should I be expecting the product roll-out this week?

    Wade
  • StampNut2StampNut2 Posts: 224
    edited 2007-08-29 11:00
    Whit, I agree with you, lots to read on this forum and very informative. I also agree that this new base is going to be very exciting, I just hope the cost is not going to be prohibitive for me being in New Zealand. Freight is a killer over here. Oh to be a Parallax agent in NZ?.

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  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2007-08-29 17:14
    Hey guys, sorry I have been out of the loop these last few days...I am fighting a nasty cold/sinus infection. All of this while the temperature is hitting three digits during the day...

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    Chris Savage
    Parallax Tech Support
  • StampNut2StampNut2 Posts: 224
    edited 2007-08-29 18:07
    Hey Chris, Take care and get well soon, We can't have you sick at this stage of the design. Three digits! damn that must be hot!

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  • D FaustD Faust Posts: 608
    edited 2007-08-29 18:37
    Get well soon.

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  • WhitWhit Posts: 4,191
    edited 2007-08-29 21:30
    Nothing worse being sick in really hot weather. Get well soon!

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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
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