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Homebuilt Robotic Platform AKA Retrobot - Page 4 — Parallax Forums

Homebuilt Robotic Platform AKA Retrobot



  • ercoerco Posts: 20,255
    edited 2010-02-23 21:14
    @Whit: Those that CAN... build. Those that can't... program. [noparse]:)[/noparse]

    ·"If you build it, they will come."
  • WhitWhit Posts: 4,191
    edited 2010-03-02 02:54
    For those who want to give this a try...

    @Ken, Just noticed the name on you pic. Must be the smarty pants side of the family...


    "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) : 3/5/2010 4:39:32 PM GMT
  • MikerocontrollerMikerocontroller Posts: 310
    edited 2010-03-02 03:05
    Any fire-breathing robot (such as Kevin's Junk Bot) that is part of this family should be called Our Son (like arson?).· Here·are some more progress pics on my new experiment.· It's constructed from·a PS2 mouse carcass so I'll call it AutonoMouse.· There will be a rear-facing· 128x128 uOLED display.· The brain power is a Basic Stamp BS2sx kit.· The Tamiya gearbox will be controlled by the Pololu Micro Dual Serial Motor Controller.· Wheels are 56 mm.·· A PING is standard equipment but IR detection is being considered.· ·The project is currently mocked-up and no wiring or programming has been done yet.· Every project in this thread is worth following so keep us all posted!

    Post Edited (Mikerocontroller) : 3/2/2010 4:02:43 AM GMT
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  • Martin_HMartin_H Posts: 4,051
    edited 2010-03-04 02:50
    This was a really interesting thread. Those motors are really tempting because they're so cheap.
  • ercoerco Posts: 20,255
    edited 2010-03-05 01:07
    @Ken & PhiPi: I really want to see those gorgeous Rich Cousin bots rolling. Please post some videos when you can!

    As you saw in my latest video, Poor Cousin is a bit more streamlined now with rounded corners and a tapered nose. But a nice·racing stripe like you have might be just the ticket...

    ·"If you build it, they will come."
  • Roy ElthamRoy Eltham Posts: 2,996
    edited 2010-03-07 06:48
    Hey erco,

    I posted a video of my version of the "Not So Poor Cousin" robot doing it's first run going back and forth on my carpet a couple times.

    I've attached a couple of pictures of it to this message.

    · Roy

    Check out the Propeller Wiki·and contribute if you can.
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  • ercoerco Posts: 20,255
    edited 2010-03-07 07:03
    WOW, Roy! Sweet, silent & elegant! OK, not silent, but a nice high-tech hum. Is that sound the PWM coming out of the HB-25s, or their cooling fans?
    And I love the "Not So Poor Cousin" in the LCD display. A very nice homage to my humble bot...

    Beautiful, perfect 180 turns, you must be using encoders. Now I'm jealous! Yours is the first video of the Parallax wood bases I've seen moving, and it is really moving nicely! What's next? Are you going to beat me to world domination with your Propeller chip?

    Very nicely done. Keep up the excellent work!

    ·"If you build it, they will come."
  • Roy ElthamRoy Eltham Posts: 2,996
    edited 2010-03-07 08:58
    The hum is the cooling fans on the HB-25s, although there was a little added hum from my PC that was next to me while filming. If I turn up the speed a bunch then you can start to hear a little bit of motor sound, but these things are very quiet.

    As for the motion, you shouldn't be jealous. Yours still has better code for accurate odometry. The Wheel Kits come with encoders and interface directly to the HB-25s, so I must admit motion is pretty easy. I am using an object I got from the OBEX to drive it. It's just telling the motors to go until X counts go by on the encoders, and it doesn't seem to be handling things like one wheel going a little faster than the other. However, it's pretty close, as is, without that, because the wheels don't slip much and the motors/HB-25s seem to be matched well. I want good straight lines even with carpet and small bumps (like your Retrobot), so I'll need to do a little more on the code for driving it.

    I don't think I will beat you to world domination, but I want to get all those PING's working as well as some other sensors. So it can drive around and avoid stuff. I've also got an XBee module to stick on there so it can communicate with my PC while running around the house. Oh, and I also plan to make an upper "cargo" deck for it using my CNC machine that I am putting together.

    Check out the Propeller Wiki·and contribute if you can.
  • PrettybirdPrettybird Posts: 269
    edited 2010-03-07 11:42
    Always had a soft spot for home made stuff. I got a post on Ebay to show my new robotic platforms here. I am an avid Parallax fan and you guys are great. I call them the Highower series ( named after the big guy in the old nerd movies ). Not selling to well, but not surprised. I am starting to hit hamfests again ( where it all began ). I was always a better technician then salesman I admit. Contact me if interestted. I am also listed as Prettybird248 on Ebay. I agree with Erco in some relay stuff. In many indistrial controls relays are still the norm. They can go for years with little on no maintanence. I am also old school and always updating.
    · I built it, now waiting for them to come. lol

    Post Edited (Prettybird) : 3/7/2010 12:47:58 PM GMT
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  • PrettybirdPrettybird Posts: 269
    edited 2010-03-07 12:34
    ·Here are a few more pics following my previous post. These units are designed for easy expansion without getting too big and hairy for the room. Designed for small rooms or apartments. Now by bird has house pet compatition. He chases them. lol·

    Post Edited (Prettybird) : 3/7/2010 12:46:25 PM GMT
  • WhitWhit Posts: 4,191
    edited 2010-03-07 13:48

    Your bot looks great and the video is very impressive!


    "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
  • ercoerco Posts: 20,255
    edited 2010-03-07 17:27
    @Prettybird: You HAVE been a busy boy! Kits are great, and get more people building & learning. Scratch-building is the big next step that scares some people, but it's great to see that you dove right in and "built it". I sure hope "they come", or I'll have to change my Forum slogan! I'll have a peek at your EBay stuff.

    @Roy: Odometry is "FUN". That is, start with the word FRUSTRATING and remove one letter at a time until only FUN remains... [noparse]:)[/noparse] I really like how quiet your bot is. That's a nice quiet motor & tire combination. My Retrobot roars merrily along. At least there's no chance it will hit a sleeping dog/baby/parent. We hear it coming!

    ·"If you build it, they will come."
  • ercoerco Posts: 20,255
    edited 2010-03-09 18:35
    The drive motors are on sale for $7 through 5/1 at

    ·"If you build it, they will come."
  • ercoerco Posts: 20,255
    edited 2010-03-12 16:42
    My article on Retrobot (Poor Cousin) is currently·in the May/June issue of ROBOT magazine, and the software & descriptions·are now available online at·. Although not mentioned by name, the Pathfinder v1.0·code function·was generally described in the article, and·is demonstrated in the video at·.

    ·"If you build it, they will come."
  • WhitWhit Posts: 4,191
    edited 2010-03-12 20:37
    Fantastic new video·erco! I'll bet there are a few RetroBots under construction at this moment.

    Edit - Just downloaded the code and the code description. Thanks so much!


    "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) : 3/29/2010 4:09:49 PM GMT
  • TritonTriton Posts: 9
    edited 2010-04-03 19:06

    Cut my base and middle platform.

    Still need to add a stamp, Ping. Testing it with a RC. Those motors are smooth and quiet.
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  • WhitWhit Posts: 4,191
    edited 2010-04-04 19:54
    Looks great Triton! I like the shape of your base and platform.


    "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
  • TinkersALotTinkersALot Posts: 535
    edited 2010-09-18 09:05
    This thread is a really great "family album" .
  • ercoerco Posts: 20,255
    edited 2010-09-18 15:12
    @Tinkers: I agree! So many great robot photos & descriptions here for motivation. I encourage everyone to share videos of their robots in action, it's so interesting to see what everyone is up to!
  • HumanoidoHumanoido Posts: 5,770
    edited 2010-09-24 11:36
    erco wrote: »
    My article on Retrobot (Poor Cousin) is currentlyin the May/June issue of ROBOT magazine, and the software & descriptionsare now available online at Although not mentioned by name, the Pathfinder v1.0code functionwas generally described in the article, andis demonstrated in the video at
    Erco, congratulations! And congrats to all who created those wonderful robots!
  • TtailspinTtailspin Posts: 1,326
    edited 2010-09-25 08:32
    Lot's of Ideas and Inspirations from this Thread..
    Thanks to all.

    Some Pictures of the Second Mobile Platform I built for testing stuff.
    This Platform is scheduled for Termination and Recycling...
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  • RobotWorkshopRobotWorkshop Posts: 2,307
    edited 2011-01-01 19:29
    Well, instead of working on some larger robot projects over the holiday I decided to try and make a robot mostly from an odd assortment of left over random parts. I'm using these surplus drive motors to make a slightly smaller replica of the Steve Norris Baxter robot that appeared in Robot Magazine. The kids thought the robot was cool and wanted me to make one for around the house. This robot is a bit smaller so he'll be nick named Baxter Jr.

    It's coming out good so far. I've attached an early picture of the drive system. The four upright supports will hold an aluminum tray for all the electronics. The H-Bridge is mounted on a piece of plastic that slides in vertically in the vertical struts. The power is a 12v 7ah battery sitting right between the motors. Everything just fits. There is room between the wheels and outside edge of the trash can to mount quadrature encoders for each wheel. I'm going to try the printed ones like Erco has been using on his robot bases.

    I have the initial part of the head done too and the servo opens/closes the door perfectly. After I do some more work on the drive and get that wired I'll wrap up the head assembly and get some more pictures.

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  • ercoerco Posts: 20,255
    edited 2011-01-01 19:35
    Gotta luv them motorz! Looks like the start of a great robot.

    Robert, you must have several HERO 2000s laying around. Are your kids interested in them? What's the most amazing thing you've done with them?
  • RobotWorkshopRobotWorkshop Posts: 2,307
    edited 2011-01-01 19:47
    The kids definitely enjoy the robots and I always try to have at least one of the kids help out so I can teach them. My 9 year old had his friend over and they helped with installing the base in this particular robot. Although you can't see in the picture it is using ball castors underneath at the front and rear. It's actually interesting that you mentioned HERO 2000. If you look close at the picture the aluminum panel on the very bottom was a salvaged piece from a HERO 2000. Part of it was mangled beyond repair (replaced by a new original part) so instead of pitching the old one the bad sections were cut off and then what was left ended up being perfect to reinforce the base. Nothing went to waste. The plastic can alone isn't strong enough without the extra support.

    Those HERO 2000's are still fantastic robots. I'm just about done rebuilding one for a friend.

    What's the most amazing thing? Well, HERO 2000 (and friends) have made many trips over to school (only a couple blocks away) and does an excellent job entertaining the kids in class. I think the coolest thing was on my son's birthday. HERO 2000 used an inflatable light saber and he moved it around making noises which was perfect for the Star wars themed party.

    This year I'm sure that HERO 2000 will be back in class and this time he'll have several custom homebrew friends come along too.....
  • RobotWorkshopRobotWorkshop Posts: 2,307
    edited 2011-01-02 19:50
    Here are a couple more pictures. It is still going to need a lot more work. Next is wiring and some of the other basics so that it can move on it's own. After that encoders and a few more sensors. Not bad for a robot on a budget made from mostly leftovers.

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  • ercoerco Posts: 20,255
    edited 2011-01-02 19:56
    Robert: Looks great, I'm a longtime fan of trash can robots!

    But hey, at least I made an effort to disguise the trash can: I flipped it upside down!
  • Martin_HMartin_H Posts: 4,051
    edited 2011-01-19 18:48
    Erco, I have a question for the master of plywood robots. If I wanted to build a robot with a diameter of about 18 inches or a bit less, but I would likely put some risers and an upper deck on it. How thick a piece of plywood would you use? Would you use birch plywood or would anything reasonable do?

    After March cub scouts will start ramping down and I am hoping to have more time for my own projects.
  • ercoerco Posts: 20,255
    edited 2011-01-19 20:07
    If you're planning to build an upper deck, I'd use 1/2", or better, use 3/8" with some additional cross-bracing (1x2's or such) framework that strengthens the lower deck where your risers connect.

    Birch is fine, and most any type is acceptable. But finding unwarped plywood at Home Depot is challenging these days. :)
  • Duane DegnDuane Degn Posts: 10,588
    edited 2011-01-20 13:24
    Hobby shops often sell "aircraft grade" plywood. It's used a lot in making RC airplanes. It's good stuff (and expensive). The thickest I've seen aircraft grade is 1/4".

    erco, I have a plywood bot I'll post one of these days (soon).

  • Duane DegnDuane Degn Posts: 10,588
    edited 2011-01-21 15:27
    Here's a robot with a plywood base.


    It started out as a BoeBot. I changed the controller to a Propeller. The board on top is an upside-down Propeller Proto Board. I added half a breadboard to the backside and ran some female headers along three sides of the breadboard with power and the Propellers IO pins.

    It was plenty of fun but then I found these wheels online and knew I needed to add them to my robot. I couldn't arrange the wheels in a triangle with the BoeBot so out came the plywood. I like the looks of a hexagon better than a triangle so that's how it ended up as a three wheeled plywood hexagon bot. I don't think there are any BoeBot parts left so I guess it's not really a modified BoeBot anymore.

    I'm using Dynamixel's AX-12+ controllers for power. Not the most economical way to power it. The Vex wheels have a square hole to accept a Vex axle. I made some custom hubs to mount the wheels to the motors out of our good friend plywood. I used nylon bolts to avoid damaging the plastic spokes.

    There is a RC receiver on the robot. The Propeller reads in the pulses from the receiver and figures out how fast to drive each wheel to go the desired direction and speed. I use one joystick to indicate the direction and speed. The robot can drive in any direction and the speed is proportional to the distance the joystick is from its center location. The other joystick makes the robot turn in place or rotate while it's moving.

    People often have a confused look on their face when they first see the robot. Ones first impression is it should only be able to turn in place. It's pretty fun to show them it can travel in any direction.

    I can see by the dates on my different versions of code, I started working on this in June of '09. I have had other things attached at different times. For a while I had a wireless video camera that could tilt up and down. It didn't need to pan since the whole robot could easily turn in place. I started to add a couple of sonar range finders but I think I needed them for something else.

    Here's a picture of the bottom of the bot.


    Right now it's powered by 10 AAA rechargeable batteries (I needed 12V for the wireless camera). I've also used a two cell LiPo for power.

    Sorry erco, no relays. Oh, wait here's an early version with relays.


    I guess they didn't work out.

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