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Robotics

Simple and Cheap Robotic Projects? 43

Posted by Cliff
from the automatons-on-a-budget dept.
siavash_of_stockholm asks: "I have a lot of spare time this so summer, so I've decided to be productive and make my own simple robot. It will come with some basic functions and it should move around without colliding or somehow avoid getting stuck in small areas and so on. I'd prefer to do this without using the popular Lego Mindstorm-kits and instead try to use a laptop and a controller card for the motors and a cheap webcam for vision. Has anyone in the Slashdot community made a similar project (on a tight student budget) and have some documentation of it they can share?"
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Simple and Cheap Robotic Projects?

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  • The laptop isn't a bad option, especially since you've probably already got it and the battery, but you might want to look at mini-ITX or nano-ITX, which will hopefully be available soon. They're smaller and probably consume less power.
    • Memory wire (Score:5, Informative)

      by Glonoinha (587375) on Tuesday June 15, 2004 @09:48PM (#9438000) Journal
      Check out the Robot Store [robotstore.com] and pay attention to all the cool things like engines, logic modules, and memory wire.

      Have fun, make me one too.
    • Re:Laptop? (Score:2, Informative)

      I looked into that the other day and found the MINI-itx cards to be ideal for this project. First of all they're very small, second they don't consume much power. I found a nice power simulator [mini-box.com] and noticed that with the EPIA 5000 I might be able to get 20W even in Network Mode.
    • A GameBoy [circuitcellar.com] makes an awesome microcontroler for home robotics projects. 4 MB of flash memory, 16 MB of SDRAM, various inputs, a nice LCD for output.

      Charmed Labs [charmedlabs.com] makes a great interface card and software to interact with the gameboy. This card can (but isn't required to) interface with many of the lego sensors and motors.

  • Johnny Sokko and his Flying Robot
    http://www.dalekempire.com/GiantRobo1.html
  • by WarPresident (754535) on Tuesday June 15, 2004 @09:29PM (#9437843) Homepage Journal
    Does your laptop have a parallel port? Here [ic.ac.uk], here [woodyweb.ca], and here [pilotltd.net] are good places to look for schematics/project ideas. You can scavenge stepper motors out of dead hard drives and floppy drives. Here's a nice project [seattlerobotics.org] that demonstrates building DC drive controller w/proportional speed control. Neat! I haven't built any such animals since my C64 and TI-994/a were new and shiny.
    • Also, if you are looking for a cheap means of mobility, consider building it atop the chassis of a cheap remote controlled car. this gets you a powered rear axle with a differential, plus a steering mechanism, a suspension and rubber tires. Other models feature independently controllable caterpillar style treads which can enable tighter turning radii.

      • Absolutely, I've thought of this, and intended to do something similar for a project a few years ago. I wanted to create a rover that could negotiate terrain using onboard AI with only user defined waypoints determining its path. To do it cheaply, I planned on using a remote control car with a wireless camera affixed to it on a rotatable base. The PC would control the rover via a parallel port I/O board connected to the remote control. The PC was to do the vision processing work.

        Good plan, but I got bogged
      • That is a good way to upgrade a lego robot for offroad capabilities.
    • I have some experience building robots. It has been a few years though...

      Those sites listed in the parent are neat and some good starting points. But I have some more...

      ---BRAINS---
      I might recommend something like an old HP 100LX, 200LX or similar, or maybe an old Pocket PC or Palm. A robot large enough to hold a real laptop will likely damage furniture and walls when it hits (and it IS a "when" and not "if). You are much better off using something about the same size/wieght as a PDA. This also means
    • While a parallel port seems to be a good idea, I wouldn't do it. Hooking up a motor controller to a parallel port is a good way to blow the southbridge chip on your motherboard.

      If you insist on using a parallel port for control, use optical isolation on your board (the chips are cheap and easy to obtain), and, don't try to draw drive power from the port.

      Words of advice from a proffesional...

      • Because that is what they are for...
        • buffers or driver IC's don't provide enough isolation from what a motor can produce in the form of back emf.
          • For small motors, a blocking diode is supposed to be used. I would say for all but really hefty motors. At some point, yes, more isolation would be needed - but for a simple robotic project, it won't be.

            Actually, you will be worrying more about RF interference from the motors than back EMF (which is why you should put at least some caps across the motor terminals - if DC - if using steppers, they should be placed between the power supply rails).

  • by MBCook (132727) <foobarsoft@foobarsoft.com> on Tuesday June 15, 2004 @09:35PM (#9437889) Homepage
    I'm suprised that no one has mentioned doing some simple BEAM stuff. It's not programable but it's dirt cheap and can be made with junk you probably have around the house. There is a fantastic book you can probably find near you called "JunkBots, Bugbots, and Bots on Wheels [amazon.com]. It can be funny, shows lots of simple robots, and other great stuff. Check it out, I think you'll be impressed.

    Other than that, build it yourself. Take two servos (you can get 'em pretty cheap at hobby stores) or just two little motors (make an H-Bridge out of some transistors), add a microcontroller (PIC, AVR, or Basic Stamps are self contained), some simple switches or photocells and some random stuff (maybe some wood to make a simple frame or something) and you'll have a cheap robot that you can program and mess around with.

    • Hey! That's what I did! How dare you take my idea! :p

      I got that book from the library, and built the light following bot that uses an LM386 op-amp as its 'brain'. It works well and I am happy to have done the project.
  • Stiquito (Score:4, Informative)

    by prostoalex (308614) on Tuesday June 15, 2004 @09:37PM (#9437910) Homepage Journal
    Well, first the disclaimer - I know nothing about this project that I will link to, but was pretty interested in the same thing.

    I've written a bunch of book reviews [moskalyuk.com], including those on Slashdot, and some publishers are sending me now catalogs with upcoming titles as part of their reviewing program.

    So, anyway, Wiley has this book with the robot kit [wiley.com], that they plan the next edition of some time this September, although the publisher told me before that the deadline might move into the future. I have not read the previous edition, nor have I played with it.

    It seems to have received brilliant reviews on Amazon [amazon.com] for that 1999 edition, so I'd suggest just perusing it and maybe buying the book+kit used if it's in buildable condition (i.e. not the robot that is already all built, polished, given guns and ammo, and right now just needs the ON switch to be turned).
    • I built a Stiquito, it was pretty fun. There's also and "Advanced" version of the book which involves using a microcontroller (AVR 89c2313 IIRC). It's been a while since I messed with it, but it was interesting.
  • by bergeron76 (176351) * on Tuesday June 15, 2004 @10:17PM (#9438219)
    If I'm not mistaken I believe that Scott Edwards [seetron.com] is one of the most prominent of the latest generation of robotics pioneers. His SSC and other projects have (in my opinion) helped to shape the aftermarket/hobbyist robotics industry.

    I wanted to give him due propers for his project back in 1996, but I never really had an opportunity (I was too busy studying women and beer at FSU at the time).

  • by Laser Dan (707106) on Tuesday June 15, 2004 @10:19PM (#9438235)
    I wouldn't use a laptop, then you have to have a robot big enough to carry it around. You are also pretty much limited to the parallel port for I/O.

    Look into microcontrollers (the most common are the Microchip PIC [microchip.com] and Atmel AVR [atmel.com]

    A microcontroller will give you heaps more I/O pins, and PWM for driving motors, serial ports, analog/digital converters etc Both PICs and AVRs are available with all sorts of combinations of features.

    There are plenty of resources available for both, look in newsgroups and search with google. GCC for the AVR is available for linux and windows so you can easily write C/C++ code for them. Also look into AVRfreaks [avrfreaks.net]
    Look at the newsgroup comp.robotics.misc for other people doing similar things.

    Good luck!
    -Daniel
    • by Anonymous Coward
      A microcontroller is good for simple robots, but doesn't leave all that much room for expansion later. Plus, it's not so easy to do vision stuff, even if you do use a CMUcam, there isn't much processing power.

      A good option is an industrial single-board computer. The PC104 standard is less than four inches square. Even the EBX format is usable, at abotu 5"x8". I picked up a single-board computer for less than $50 on eBay; it was brand new. And since they are designed for controlling things, they often have
    • I second using microcontrollers.

      I just wrote a basic network stack for the microcontrollers for the lasers our company produces. All the sensors measure the temperature, with feedback loops to the heaters. Several controllers control 5 or so temperatures and heaters each. The controllers are on a serial bus, with another controller for a usb connection.

      It's fun writing code knowing you only have a few bytes of memory. heh.
  • by baywulf (214371) on Tuesday June 15, 2004 @11:17PM (#9438578)
    There is some book on robotics I read that uses a Palm Pilot as the brain of a robot. The catch is that you have to build a simple serial to parallel convertor so you can interface the Palm to the servos and sensors. An old plam can be gotten for $20-$30 and it has an IR sensor, display, fast cpu and lots of memory compared to a microcontroller.
  • I'm building a submarine using a PC/104 stack. Found almost all the parts on eBay, including a relay controller and 20 channel servo/stepper motor controller, as well as the PC/104 mainboard. This [ebay.com] is exactally what I bought, but there are others.

    My requirements are way different than yours, however. I'm going to require a rather large control program onboard the sub to reach the level of atonomy I'll need for deep dives.

    Good luck to you.
    • That's cool - I've thought a lot about doing that. How will you build the body? It's tough to design something that will resist pressure but can be opened up completely for access. I had some ideas of using PVC pipe for the pressure hull and building a much lighter hydrodynamic envelope around it. The ballast tanks would live in the annular space between.

      Possibly the whole inside can be a chassis that slides out one end - but that makes it hard to connect sensor and actuators.
      • One way is to build the hull to handle the pressure, and pumping the thing up with high-pressure air (bicycle pump). Then, if you are going down to 60 feet, just fill the hull with 40 PSI or so, and if there are any small leaks, air will bubble out instead of watter getting in.
  • Interested in CNC? (Score:3, Interesting)

    by ivan256 (17499) * on Wednesday June 16, 2004 @10:44AM (#9442529)
    This may not be what you were thinking when you thought "robot" but it uses all the same control principles. Check out John Kleinbauer's [crankorgan.com] site. He's got plans that are great for a beginner. I purchased his "Brute" plans and the really walk you through every step, from finding the materials to programming. I've changed so many things from the plan since I started building that it's barely the same machine, but the plans helped me to avoid problems I'm sure I would have hit without a framework from an experienced designer to follow. Using PVC, Delrin and aluminum as materials makes the construction fairly easy with a minimum of tools too. For one section where I needed an extra precise cut I had a local metal shop make the cut on their abrasive chop saw for me, but other than that the construction has all been done on the tablesaw and drill press. It's been a fun project.
  • Productive? (Score:3, Funny)

    by phamlen (304054) <phamlen AT mail DOT com> on Wednesday June 16, 2004 @12:04PM (#9443415) Homepage
    I have a lot of spare time this so summer, so I've decided to be productive and make my own simple robot.

    Only on Slashdot would this be called "productive"...

  • Check out the Toy Robots Initiative [cmu.edu] at Carnegie Mellon's Robotics Institute. In particular, the CMUcam [cmu.edu] and Palm Pilot Robot Kit [cmu.edu] are worth checking out.
  • microcontrollers... (Score:3, Informative)

    by jotux (660112) on Wednesday June 16, 2004 @01:13PM (#9444129)
    I'm surprised no one has suggested a Basic Stamp. Personally I have stopped using them because I started needing more power on my projects, but for simple robot platforms, they are a pretty good teaching tool. If you get a BS2 kit [parallax.com] with one of the books to go a long with it, you'll basically have everything you need to get started. You wont have laptop control, but if you are interested in controlling it with a laptop I would try rentron [www.rentron] and get some transmitters/receivers and play with making it wireless. The basic stamp is limited in it's ability, but its hard to find any other kind of robot kit that comes with an entire curriculum like anything from parallax does.
    • I have to say the PICAXE controller are also a great introduction ... I paid $AU15 for a basic chip and it only takes 2x resisters to interface to your serial port.. dkownload the programming env (free) and your away.,, they are quite simple chips but have in built PWM, IC2, (dallas) 1W interface and ps2 keyboard support all built in... they are just TOO EASY!!! get an 'X' veriosn though... you will find the extra memory very usful.....
  • http://www-2.cs.cmu.edu/~reshko/PILOT/

    Has instructions and software ready made or you could base something different off of it. Pretty cheap also.
  • Check out http://tutor.al-williams.com http://www.piclist.com and http://www.avrfreaks.net
  • Control via laptop? (Score:3, Informative)

    by Satan's Librarian (581495) * <mike@codevis.com> on Wednesday June 16, 2004 @07:05PM (#9447559) Homepage
    So you want it wired to a laptop? If so, one thing I didn't see scanning the comments is Weeder Technologies [weedtech.com]' controllers. They do RS-232, which is a lot more friendly for a variety of control options than many of the parallel-port motor controllers.

    I used their digital I/O and stepper motor controllers for my 3D scanner [codevis.com] project - they're pretty good for low-res, low-budget projects.

... though his invention worked superbly -- his theory was a crock of sewage from beginning to end. -- Vernor Vinge, "The Peace War"

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