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Picture of Rocket Brand Studios Medium Tank
This is the assembly instructions for the Medium Tank from Rocket Brand Studios. This is a great little robot kit, and can be purchased as a complete kit or as a rolling chassis, ready for the micro controller of your choice --Arudino Uno, Duemilanove, Picaxe 28 board, or Gadget Gangster Propeller Board. The Medium Tank comes in lots of super-duper colors (and colours!) so be sure to stop by the website to see what is available.
 
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Step 1: Prepare

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Alright there, Skippy --Unwrap everything and get ready to get going.

You will need:
  • Little screwdrivers
  • X-acto knife
  • Soldering iron and small solder
Now, lets go ahead and talk about the elephant in the room... The laser-cut acrylic has a distinctive smell. The good news is that most of that funky goodness is in the paper backing of the plexi and not the actual plexiglass. Unwrap all the pieces by peeling off the paper plastic and get it out of the house. The smell will go with it, I promise.


Step 2: Assembly 1

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  • Start by soldering a capacitor and one red/black wire to your motor (see photo)
  • Attaching the 2 motor mounts to the motors themselves with (2) 2-56 x 1" screws and nuts.
  • Place the motor's cross member between the 2 motor mounts and place this assembly on the bottom plate
  • Secure this assembly with (2) 2-56 x 3/8" screws and nuts



Step 3: Assembly 2

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  • Attach the 2 rear wheel supports to the rear cross member (note: this is similar to the motors, but includes a screw coming in from the side --see pictures)
  • Place this assembly on the bottom plate
  • Attach this assembly to the bottom plate with (6) 2-56 x 3/8 screws through the bottom plate

Step 4: Assembly 3

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  • Find the top plate and note that the hole for the battery wires must be on the left (I'm pointing to it in the picture)
  • Install the (4) 20mm standoffs
  • Route the motor wires through the center hole and place the top plate over the bottom assembly
  • Wiggle it around a bit and get all the "tabs" to fit in their corresponding "sockets" and also get the motors to sit in their little cut-outs
  • Screw the top plate down with (8) 2-56 x 3/8 screws. It is handy to use some needle-nose pliers to get the (4) "center" nuts up-and-in-there.

Step 5:

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  • Find the electronics plate, your servo 
  • If you purchased a complete kit with an Arduino Nano and Undershield, install the (3) 10mm stand-offs. These should be installed with nuts on the underside of the plexiglass plate and the end with screws, going up.
  • If you are using a different brain (not the Nano) you will need to place your micro controller board on top of the plate and find the mounting holes that line up. If you are using stand-offs or spacers that will need to be attached via the underside of the plate, attach them now.
  • Install the servo with the shaft positioned so it is centered and screw it down with (2) 2-56 x 3/8 screws. Route the wire through the center hole
  • Prepare your switch plate. Install the 2 switches (if you want to switch the data power and motor power individually) and solder a short piece of wire between them. 
  • Prepare the battery pack. Find the (2) 2-pin leads and connect the 2 black wires to the black wire coming out of the battery pack --solder it and tape or shrink tube it. The red wire from the battery pack and the (2) red wires from the leads will be left disconnected for now, until we install the battery holder.
  • Install the battery pack to the underside of the top deck (not the electronics deck) using the (2) 2-56 x 1/4" flat-head screws (they are the black ones)
  • Run the battery pack wires up through the hole in the deck
  • Place the switch plate's tabs into the 3 socket holes toward the back of the plate
  • Finish up your soldering. The red wire from the battery gets soldered to the first switch and also to the jumper going to the second switch. (This will send power to both switches)
  • Solder the last 2 red wires (from the 2-pin leads) to the 2 switches. (This will send power to the micro controller and motors as each switch is clicked)
  • Place the electronics plate (running all the wires through the center hole) on the bottom assembly and attach it to the stand-offs

Step 6: Assembly 5

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  • Unwrap your tracks set being careful not to loose the little washers
  • Press the 2 front wheels on to the motor shafts. They should not go on all the way, leave a 1/8" or so. Also, the "teeth" of the wheel should point to the outside
  • Grab a rear wheel (with a round center hole) and slide the axle bolt through it. Now add, in this order, a washer, the small circle and then the bigger circle. Now slide the bolt/wheel assembly through the hole in the back of the rear wheel support. Attach it with the nut.
  • Repeat all this for the other side.
  • You may now (carefully) stretch your tracks on

Step 7: Assembly 6

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  • Assemble the sonar bracket by attaching the (2) 1/2's with (2) 2-56 x 3/8" screws.
  • Bore out 2 holes in the servo horn (that match the holes in the bracket) to accept the 2-56 screws. You can do this with a drill bit, of course, but it is just as easy to do with the spinning the tip of an X-acto knife in the hole.
  • Attach the bracket to the servo horn using (2) 2-56 x 1/4" screws
  • Attach the Sharp sensor (or SRF-05 or Ping) to the bracket using (2) 4-40 x 3/4" screws, (2) spacers and nuts
  • You should wait to attach the sensor bracket to the servo until you get a chance to run some code to center your servo and thus, be able to get it on straight.

Step 8: Assembly 7

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  • If you ordered the complete kit and are using the Arduino Nano, you will need to go ahead and solder together the Nano Undershield Kit. More information can be found here.
  • The instruction manual and assembly instructions can be found here.
  • Pay careful attention to the use of the jumper block and power connections.
  • Assemble the Undershield and attach it to the (3) 10mm standoffs, routine the motor wires, switch wires and servo wire out from under it.
  • Plug in the motors, switches, servo and sharp sensor. For the love of God, you MUST get the polarity and position of these wires correct! Read the instruction manual for more information!
  • Plug in the Arduino Nano into the Undershield

Step 9: Assembly 8

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  • Install the (4) 40mm stand-offs to the electronics plate. --All the holes are close to the edge, it should be easy to get the screws up through the plate
  • Attach the accessory plate to the (4) 40mm stand-offs 
  • The accessory plate is quite useful to allow you to add a breadboard, other sensors, a camera attachment, etc etc.
Note: Some microcontroller / motor shield combinations will not allow the installation of the accessory plate
Note: The picture below shows an alternative sensor

Step 10: Done!

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That's it, homie-G.

You are done. Woo Hoo!
Double check all your connections, double check the polarity of all the connections. Install your batteries. If you are going to connect to the end of the Nano board, you will be connecting to the input that goes to the voltage regulator of the Nano itself. Feel free to use alkaline batteries. If you are using rechargables (which put out a lower voltage than alkalines) you may want to use the input on the side of the nano board. This connection goes directly to the Nano and bypasses the volt reg. PLEASE check the instruction manual to learn more about these connections and how the jumper block should be installed.

Now zap some code in! I would start with the basics, testing each "system" individually. Write some simple "read ADC" code to test the sharp sensor, write some code to run the motors and check the direction and run some code to sweep your servo. If all these guys check out, well, then happy coding to you!
mrpi641 year ago

Is there any way that I could grab the files so that I can 3D print them myself? If possible, in .dtd format

s_E_v_EN3 years ago
Hey where can i found these items?? i am from phillipines.
Chris the Carpenter (author)  s_E_v_EN3 years ago
You can find this guy at http://rocketbrandstudios.com

Thanks!
deobomb3 years ago
i went to the site is there some way i can order by phone ? i cant find a number
Chris the Carpenter (author)  deobomb3 years ago
Sorry, my friend. No phone orders (I would have no way to process the payment). I do everything through PayPal. If you really, really can't do it that way, I would be willing to accept a check or money order sent to me, but you are looking at some wait time for the check to clear before I can send the order. If you would like to go this route, feel free to shoot me an email. rocketbrand (at) gmail.com
meenzal3 years ago
Not too shabby. For people interested in tank platform robots, the Rover 5 and DFRobot platforms are very rugged, and you can built a complete robot for the same $100 neighborhood. For $50 more I built this 4WD unit, Arduino driven, autonomous operation with FPV video. Most parts from http://robotshop.com --and they carry the DFRobot platforms which are the most complete kits I've found.
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Chris the Carpenter (author)  meenzal3 years ago
Hey thanks meenzal,
Yup, the DFRobot is a nice platform. Did they ever fix the issue with the treads stretching out and falling off during turns?
I haven't heard of the problem. Are you talking about the older tank platform or the Rover 5? I have a few of the older ones and after lots of use they're still going good. I only have one of the Rovers so far and haven't had any tread issues so far. But I think that there could be tread issues with it if the axles are set too close to each other --it would make for the treads being loose. As you can see in the photo, I have the axles as far apart as they can be and the treads are tight on the wheels. RobotShop has a little blue platform they sell for about $50 and uses hard plastic treads that come in sections you have to assemble. I hated those because there was no way to adjust them to the tension I wanted. They work ok but I like the rubberized treads better.

I hadn't seen the platform you used until your Instructable (thanks!) I think I may get one and try it out. They are pretty attractive with the colored laser cut panels.
Chris the Carpenter (author)  meenzal3 years ago
Thanks for the kind words. Yup, I am pretty happy with this guy. It is actually around version 7 or 8, with I don't know how many different designs I cut from cardboard. It is a nice, simple, solid robot.

In terms of the rover, I find myself over at Lets Make Robots a bit and I have seen maybe a 1/2 dozen forum posts go by about the tracks slipping off. Many of them mention the issue occurring when returning to a narrow stance after being at a wider one (which would make sense, they were stretched!). I dunno, I don't have a dog in the fight either way, I guess. It is a good looking bot though, and I saw some Spark Fun videos of these things bouncing down stairs so, there you go..

Oh, and I totally agree with the segmented tracks issue. --Its pretty simple really, you can't make something out of plastic, that small (with that small of a pivot) and make it sturdy. I have broken so many Solar Botics treads, I have lost count. I stick with rubber treads, period. I found the Pololu tracks (the ones on the tiny and med. tanks) a few months ago and so far, I am very, very happy with them.
kokpat3 years ago
Does the kit included source-program for references ?
Chris the Carpenter (author)  kokpat3 years ago
Hey kokpat,
Ah yes, sample code...
Well, Christmas sorta snuck up on me and stole my time. Yes sir, there will be some sample code up very soon (I promise). For now, there is an instruction manual with all the pinouts etc for the microcontroller, and I do have a bunch of "getting started" stuff, which is specifically for my RocketBots, but is pretty universal and can help you get going. Not to mention, I am a nice guy and actually return emails and answer questions.

Everything is here: http://rocketbrandstudios.com

Word up,
Chris
Thx for your reply.
Awesome Instructable Chris! We at Eaglesnest Robotics will cherish this build for our students.
marc.cryan3 years ago
Nice!