Tutorial: Building a Mech using DBs Bracket System

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    darkback2 darkback2 is offline Mech Warfare Veteran
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    Building a Mech using DBs Bracket System

    Difficulty
    Moderate Some experience necessary
    Estimated Time
    Several days
    Skills Required
    Using a band saw drill press and vice
    Parts Required
    Scrap Aluminum
    an SSC-32
    14 HS 645 MGs
    Tools Required
    Basically a drill press and a band saw.
    So You Want to Be a Part of Mech Warfare

    The Basic Walker

    Here you have two options. Since your reading this, lets say you have one option. That would be a four legged robot. The one that I would recommend is the Quadrod by Crust Crawler. I wouldn’t get the complete kit, instead just get what you need, the hardware only set up. It will cost you $119.00

    http://www.crustcrawler.com/products...ex.php?prod=18

    Note: Since I embarked on writing this tutorial yesterday the quadrod has been discontinued. Included in the package of PDF files are all of the brackets you would need to build either Charlie or Squidword. Both will be highly capable mechs, but pretty difficult to build. The frames for each one cost about $10 in aluminum...So good luck.

    Servos

    Next up for the servos. Assuming you are going to run two guns and one camera all with pan and tilt capability, then you will need 6 servos in addition to the 8 you need for the quadrod. So you will need a total of 14 servos. If you go with HS 645 MGs you should have plenty of payload capacity. 14 will cost about $503.86

    Servo Extension Cables

    Given the size of this robot I would expect to need some servo extension wires. These increase the distance the servo can be from the controller. While its best to order these once you know how far the servos have to be from the controller, for those with less patience, just get the 12 inch extensions for each of the 8 servos. They cost $3.50 each...$28.00

    http://www.trossenrobotics.com/store...bby-servo.aspx

    A Wifi Camera System

    A wifi camera will allow you to “see” through your robot’s eyes. $41.99

    http://www.unityelectronics.com/product-product_id/4602


    A controller

    While this is a place where you could be flexible, your best bet would be to go with a serial SSC-32. This will allow you to control both your servos, your guns, and your cameras pan and tilt system. $39.95


    http://www.trossenrobotics.com/store...ontroller.aspx

    A Wireless Bridge
    This is how you will connect your control computer to the SSC-32 (insert chip of choice here). I would recommend a pair of xbee pros. These take the place of a serial port and at $36.95 per will run you $73.90

    http://www.trossenrobotics.com/store...ee-Zigbee.aspx

    7 inches of 25/25 extruded aluminum. I have some laying around...You should get a couple of the T ends also.

    http://www.8020.net/T-Slot-1.asp

    Finally tools.

    Here I would look into the following assuming you don’t already have a good way to cut and shape aluminum:

    1) a good set of precision screw drivers...Magnetized would be nice...$20
    A Drill press and set of bits. I got mine from Home depot for about $200
    A band Saw, or jig saw...possibly both. Get a fine metal blade. I got mine from home depot $100 and maybe $30 for the fine blade. (a metal blade is a must. A regular blade simply won’t cut strait.
    A big clamp $40 or so
    2 pairs of sheet metal pliers. The flat section on the ones that I use are about 2” wide. $20 or so...probably less.
    A dremel with a small cut off wheel and an angle grinder are helpful. You can also use a disk sander or even a hand rasp...though these will make the job take a lot longer.

    Miscilaneous hardware. Throughout the tutorial I will be asking you to use various screws, nuts and bolts. You probably want to keep a box on 3/4 inch number six screws and bolts to match. For Bolts I generally keep both locking and non locking bolts around. With the T-slot extruded aluminum I have found that using round head 1/4 inch bolts less than an inch long works great, and doesn’t interfere two much with the project and the placement of electronics.

    This brings the total up to about $1,216.00. Without the guns or batteries...but we’ll get to them later.

    Step One...

    Once you settle in on your base kit, see quadrod above...then go ahead and order the kit, the servos, the extension cables, and the SSC-32 (insert chip of choice here) You’ll probably want to take a trip to your local electronics shop to pick up a pair of RC batterys...I got mine at radio shack...not sure how much I spent on them, but the were what they were. Add to that a charger and you’re good to go...

    After the nice brown truck comes by go ahead and build the frame of your robot. Throw in your servos, and you should have something that looks a bit like a robot.

    Step Two Mounting Things.

    Find the center of the backbone of your quad. Draw an X in the backbone on either side of the center line one inch away, so you have two X’s that are two inches apart.

    If you can without damaging anything, Drill two quarter inch holes all the way through the robot from front to back. Get Two 1/4 inch screws that have rounded caps and are long enough to reach from the top layer through the bottom layer of your robot. Add washers and nuts, and screw down loosely.

    Cut 3 inches off of the extruded aluminum. Slide it under the rounded bolts so that it is in line with the frame of your robot, and try to get it centered on your robot. Once it is go ahead and torque down the bolts holding it in place.

    Now cut the remaining 4 inches in half. Now you have two two inch pieces. Using the T brackets, mount them on either end of the 4 inch long piece of Aluminum already mounted on the center of your robot.

    Get some aluminum Sheeting. Print out the SSC-32 mounting plate PDF file that should accompany this tutorial.

    Cut out the Drawing on the page.

    Using spray on adhesive glue the picture onto some aluminum sheeting. Using your band saw rough cut out the part.

    [youtube]ZI-jn7d_qLw[/youtube]
    After you have the part cut out, take it over to the drill press. Its best to use bits that are a size or two bigger than the nuts you are going to use. This will account for any sloppyness in where you are drilling the holes. Tap all of the holes using a 9/64ths bit. I like to work my way up in bit size so next you would drill out all of the quarter inch holes with a 5/16ths, and finally all of the half inch holes last.

    I like to round off the corners using an angle grinder. You don’t have to do this...I just don’t like having sharp edges.

    Now take out your SSC-32 and a marker. Center the SSC-32 over your aluminum board. Using your marker, mark where the four mounting holes should go on your aluminum board. Using the drill press and a 9/64ths bit, drill holes where you have marked with the sharpie.

    Once you have all of your holes drilled, spray the paper and glue side of the aluminum with a liberal amount of WD-40. Wait a few minutes (about 5) and carefully peel the paper away from the aluminum. You can dissolve any remaining glue using WD-40. Use dish soap to remove the WD-40. I usually run the brackets through the dishwasher just to get rid of all of the gunk that builds up.

    Now that you have your SSC-32 mounted, its time to make the bracket that will form the main backbone for your camera and guns.

    Print Out the PDF file labeled Top Bracket. You will need to either use legal sized paper to print this bracket, or print it on two pieces of paper and tape them together to make the right shape. Using scissors or a paper cutter rough cut out the bracket and glue it to a piece of aluminum sheeting. Using the same methods described in the SSC-32 mounting plate cut out the bracket.

    The top servo mount in the center of the sheet will require that you either use a half inch drill bit, and then use a hand saw to cut out the remaining shape, or use a dremel to cut out the inside square. Be careful to not cut too close to the edge when cutting out that bracket.

    Use the same technique to cut a hole out of the front of the bracket. This is where all of your wires will pass through, and will make connecting things easier.

    Once you have the bracket cut out, you can go ahead and mount it on your robot.

    Mounting Guns

    I like to use the Defender gun from Walmart. I know there are cheaper guns on the market, but the defender gun has a clear plastic body which makes it easy to see what you can cut, and what you need to leave behind. I'll probably mount two on squidword for the airsoft class round, and one with two sets of rockets for the hardcore class.

    Another thing that is nice is that I will be able to quickly swap the weapon systems between charlie and squidword which should help with saving money.

    [youtube]w2GI1wQdFOc[/youtube]


    Mounting Batteries.

    Quads can be very tippy robots. With a hexapod, or six legged robot you can use what is called a tri-gate. With a tri-gate a robot always has three legs on the ground. While with a poorly balanced hexapod some tipping is possible having three legs on the ground at any given point in time forms a stable base. With a quad, it is difficult because the leg distribution is different. Quads require either a weight shifting ripple gate in which one leg is moved at a time, and the other three legs move in different ways to balance the robot, or a dynamic gate in which the robot briefly balances on two legs while the opposing two move.

    Because batteries are heavy they make good ballast for balancing a quad. For that reason you will want to mount the batteries as low as possible. If your robot has more than one deck, then the lower deck is where you want to put your batteries.
    You can just velcro the RC battery in the center of your bottom deck. If you build Squidword, or are using a model without a bottom deck, use the method described above to cut out the battery mount. The file is called Bottom Bracket PDF.

    Making Charlie

    Print Out 2 copies of all of the PDF files in the Charlie Folder.

    Rough cut each picture.
    Use spray on adhesive to attach the pictures to flat aluminum stock.
    Using a bandsaw cut out each of the shapes.
    Move over to the drill press and drill out each of the holes.

    Body Panels

    Use a dremel or jig saw to cut the slots out. Wires will feed through these slots passing wires through to the rest of your robot.
    Once you have the body panels cut, lay them off to the side.

    Shoulders

    Use a dremel or jig saw to cut out the bottom (lift) servo opening.
    Use an angle grinder or sander to round the lever mount.
    Use the pictures as reference.
    Once the holes are drilled out fold the shoulder at the top and bottom to form the top (twisting) servo mount.
    Put a 1 inch long 1/4 inch screw through the bottom of the mount. put a bolt on the bolt.
    Remember that two of the shoulders should fold in one direction, and the other two should fold in the other.

    Elbows

    The elbow joints have several complex folds. Refer to the pictures to help ensure they are folded properly.
    Use the above techniques to print, cut out, and drill the holes in the elbow brackets.
    Fold the brackets from the inside out. This will allow you to grip the metal properly as you make a fold.
    Using a piece of 3/4 inch square tube, round out all of the folds.

    Front, Back, and Side Panels
    - Use the above techniques to make the front and side brackets. They are all the same bracket. For the side brackets you can cut off the side flanges. With the back bracket you do not have to fold in the side flanges.

    Making Squidword

    Parts:

    Body
    Body Bracket
    Bottom Bracket
    2 Double servo brackets with the edge mount cut off.
    Mounting Plate
    Top Bracket
    2 2” pieces of T-slot extruded aluminum

    Legs (each)
    2 basic hinge W
    1 offset basic hinge W
    2 single servo brackets

    Electronics
    1 SSC-32
    1 Nicad Battery
    12 Hitech HS 645 MG or better Servos

    Assembly
    Cut out and bend all of the brackets using the pictures as reference.
    Take out the body bracket. Using # screws bolt the bottom bracket on so that the tongues from the body bracket are underneath the bottom bracket and the screws stick out the bottom.
    Attach the two pieces of t-slot aluminum to the top of the body bracket using rounded 1/4 inch bolts.
    Mount the SSC-32 on the mounting plate and set it aside for now.
    Using 1/4 inch stand offs bolt the double servo brackets inside the body bracket using the pictures for reference.
    Slide 1 basic hinge w over each of the double servo brackets again using the pictures for reference.
    Mount servos inside all four brackets.
    Attach a single servo bracket to each of the 4 basic hinge w using the picture as reference.
    Slide a basic hinge wide over the single servo bracket.
    Attach an offset basic hinge w to the basic hinge wide so that the hinge flanges are on the bottom. Do this for each leg.
    Mount a servo in the remaining servo bracket, and slide it into the ofset servo hinge wide so that it sticks out on the bottom.
    Now mount the SSC-32 plate on the top of the robot.
    Finally mount the Top Bracket over the SSC-32.
    Attached Files


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Replies to Tutorial: Building a Mech using DBs Bracket System
  1. Re: Building a Mech using DBs Bracket System

    Incredible tutorial DB, the video really helps explain things too. I've got a few servos and aluminum brackets started, if I can find them since moving.
        

  2. Join Date
    Dec 2007
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    Re: Building a Mech using DBs Bracket System

    /Applaud

    Great tutorial, +Rep DB!
        

  3. Re: Building a Mech using DBs Bracket System

    That's brillant DB!

    -Crabfu
        

  4. Join Date
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    Re: Building a Mech using DBs Bracket System

    Quote Originally Posted by crabfu View Post
    That's brillant DB!

    -Crabfu
    Coming from you...I'm blushing.

    Thanks Everyone. I just managed to upload the SSC-32 controller software, and the PDF files for these project. Seriously I hope this helps a bunch of people do what they want and save money doing it.

    DB
        

  5. Re: Building a Mech using DBs Bracket System

    Awesome work! I really appreciate the video as it makes things clear and easy to follow. I even learned something. I had never done the relief cuts with a bandsaw before. Nice!
    "If A is a success in life, then A equals x plus y plus z. Work is x; y is play; and z is keeping your mouth shut."
    -
    Einstein

    Don't be a HelpVampire
        

  6. Join Date
    Jul 2008
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    South Sphincter Idaho
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    Re: Building a Mech using DBs Bracket System

    Very nicely done.

    This a good example of what can be done without having a shop full of fancy tools. I like it.

    Gary
    Team Maggot---Mechs. "Bheka" (retired), "Maggot Mk.3(A)"
    " Keep your stick on the ice ".... Red Green
        

  7. Re: Building a Mech using DBs Bracket System

    Center line marks on the holes in the Body and Front/back panels would be extremely helpful.
    "If A is a success in life, then A equals x plus y plus z. Work is x; y is play; and z is keeping your mouth shut."
    -
    Einstein

    Don't be a HelpVampire
        

  8. Join Date
    Dec 2007
    Location
    Whidbey Island, WA
    Posts
    1,718

    Re: Building a Mech using DBs Bracket System

    yeah...right now some of the drawings are more user friendly than others. I'll try to keep cleaning them up as I have time and keep reposting them as well as posting other brackets as well...
        

  9. Join Date
    Dec 2007
    Location
    Whidbey Island, WA
    Posts
    1,718

    Re: Building a Mech using DBs Bracket System

    Updated the brackets to include center lines for all of charlies brackets.

    Hope that helps.

    DB
        

  10. Join Date
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    Re: Building a Mech using DBs Bracket System

    updated mechmover...enjoy
        

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