Max The Megapod Assembly Instructions

This page is not yet complete. Do not attempt to use it yet to build Max the Megapod.

BILL OF MATERIALS (BOM) FOR VORPAL H12 HEXAPOD

Notes on Sourcing Parts

• These instructions assume you have purchased a kit from us. If you are sourcing your own parts, please be aware of the following additional information:
  • If you are sourcing your own parts, you need to build the switch/battery connector assembly. For diagrams see Max The Megapod Battery/Switch Construction.
  • Also see important information on that page if you are sourcing your own BEC.
  • If you are sourcing your own Bluetooth modules, please be aware that you will need to configure them to auto-pair and to have a UART speed of 38400 BAUD. Every module brand is a bit different so it's not possible for us to give you universal instructions on how to program them. We assume that if you source your own parts you are familiar with how to configure Bluetooth modules using AT-commands.
• Full kits of parts as well as individual parts are available on The Vorpal Robotics Store. If you are new to Arduino and robotics we strongly recommend you purchase a kit instead of trying to self-source parts. The kits cut 3 to 4 hours off the build time, bringing it to typically 1.5 to 2 hours. The kits have all soldering done, programs are already loaded on the Nanos, Bluetooth modules are properly configured, and you know you have all the right parts to work together.

ROBOT BOM

• Electronics:
  • Passive Piezo Buzzer module and 3 wire cable (see image)
    

    Passive Piezo Buzzer Module
  • Arduino Nano, 5V, 16 mHz, ATMEGA328 or similar (marked RM in our kit to indicate it is pre-loaded with megapod robot software)
  • Rotary potentiometer, 10K Ohms, 6mm shaft diameter, with 3 wires pre-soldered. Also, matching dial cap and nut.
  • 1 x HC05 BlueTooth Module with 4 x F-F jumper wires for making connections (Note: the HC05 has six pins but only four are used in this project. Also, this is in the Gamepad Parts bag if you purchase our kit.)
  • 1 x Servo Controller module (Adafruit 16-channel 12-bit I2C PWM/Servo driver or Adafruit clone) with F-F jumper wires for making connections, plus 1 two-pin shunt tying V+ to VCC
  • 12 x MG958 servo motors and associated servo horns (you will only use the single-arm horn).
  • 1 x Power distribution wiring harness with on/off switch, Fuse, Tamiya battery connector, 3A 5V BEC, and servo extension connectors. If you are self-sourcing see our Circuit Diagrams.
• 3D Printed Parts:
  • 3 Robot Base Parts and bottom plate to hold the parts together.
  • 4 Cap parts which screw together to form the cap of the robot.
  • 6 x Legs
  • 12 x Servo Stops. These parts hold the servos in their compartments both in the base and the legs.
  • 12 x Leg Hinge halves with Leg Hinge Rings. The rings stop layer separation issues.
  • 1 x Electronics Caddy to hold nano and servo controller
  • 2 x Eye/glasses Decoration
• Miscellaneous:
  • 12 x 608 Skate Bearings
  • 8 x 20mm diameter ceramic magnet, north pole marked. 6 are for robot top, 2 for eye/glasses decorations
  • 12 x socket head cap screw, 3mm diameter by 8mm long (for servo horns)
  • 12 x #6-32 x 1/2" button head screw to fasten together base and cap parts.
  • 1 x L shaped hex driver, 2mm, for both kinds of screw used in the kit.

GAMEPAD BOM

• Electronics:
  • 1 x Battery/Switch Wiring Unit with 9v battery clip. (Note: the gamepad requires no BEC so you can use this fact to distinguish from the robot wiring unit)
  • 1 x button matrix with associated connecting wires
  • 1 x Dpad Button module with associated connecting wires
  • 1 x HC05 Bluetooth module and four wires to connect it
  • 1 x microSD Card Reader module and six wires to connect it, and a microSD card that is compatible with the Arduino SD library. NOTE: This is only included in the DELUXE version of our kit, not Bare Bones. A microSD card is required for record/play features to work. The capacity should be 1gb or less. Strongly recommend FAT file system and 512 byte allocation unit size (use FORMAT on your computer to reformat if necessary).
  • 1 x Ardunio Nano, 5V, 16 mHz, ATMEGA328 or similar (marked "G" in our kit to indicate it is pre-loaded with Gamepad software). Note: For MAC users it is far easier to get Scratch to work if the gamepad Nano uses an FTDI serial chip instead of a CHG34X chip. Our kits use the more expensive FTDI version of the Nano in the Gamepad for this reason.
• 3D Printed Plastic Parts:
  • 1 x Gamepad base plastic part
  • 1 x Gamepad top plastic part
  • 1 x Gamepad button carrier
  • NOTE: Gamepad Base versions before April 2018 also required 1 x Switch Adapter
• Fasteners:
  • 4 x #6-32 x 1/2" screw to hold cover on gamepad (4) and also to hold switch adapter on base (2)
  • NOTE: Gamepad Base versions before April 2018 also required 2 more of these screws to hold on the switch adapter.

3D Printing the Plastic Parts

This project has been finely tuned to make it easy to 3D print. No supports are required for any of the parts (there is a support built into the models for the CAP parts). In some cases you may want to use brims or rafts to help parts adhere to the print surface. There is some significant bridging, never farther than about 30mm (1.2"). It is important to tune your printer and make sure it can handle the bridging before attempting the large parts, otherwise you may waste a lot of plastic!

This page assumes you have basic familiarity with 3D printing and 3D printing terminology. If not, you might want to reference online materials such as youtube videos or information from your 3D printer manufacturer before attempting this project.

If you are 3D printing the plastic parts (as opposed to buying them pre-printed), here are some tips.

• MINIMUM PRINTER REQUIREMENTS
  • The bed size should be at least 200mm cube (about 8 inches cube). The largest parts are the hexapod base (3 parts) so it is the limiting factor on bed size.
  • A heated bed is strongly recommended, especially if you are printing in ABS.
• RECOMMENDED PLASTICS
  • ABS, PETG, and PLA all work well. However, because there are some very large parts, ABS may cause you some warping issues if you don't have a heated bed and a printer tuned well for large parts. PLA is generally easier and has fewer issues with corners peeling off the print bed.
  • We use eSun PLA PRO for this project. PLA PRO is a little more flexible and stronger than typical PLA.
  • This project requires less flexibility than the smaller Vorpal The Hexapod project, so ABS is less required for this project.
• PRINT SETTINGS. We print using the following settings on a Lulzbot TAZ 6 with 0.5mm nozzle:
  • 0.4 layer thickness (or whatever layer thickness is optimal for your printer)
  • 2mm walls (i.e. four perimeters)
  • 1.6 mm top and bottom (i.e. four layers)
  • 25% infill
  • You can print with thinner layers if your printer does not support 0.4mm layers or if you want a more refined look, it will just take longer.
• BRIMS AND RAFTS
  • Brims or rafts are recommended for the following hexapod parts: Base, Legs, Electronics Caddy, Cap. This ensures proper bed retention to avoid warping. These parts have relatively little contact area with the print bed, or have certain sections with little contact. If you have a very well dialed-in printer and have no issues with warping or corners curling up during prints, you can try them without brims. We don't use brims on anything but we've printed thousands of parts and we keep our printers very well tuned all the time with weekly maintenance and adjustments. These parts are large so if you don't use brims and things don't work out you might kill half a roll of plastic ... so maybe just use brims, it only adds a few minutes of cleanup time.
  • Brims/rafts are not recommended on any of the other parts. The other parts generally have enough bed surface contact that they will print fine without brims. Your mileage may vary however and it is recommended that you keep a close eye on the first few layers of the print to make sure everything is sticking properly. If not, you can cancel the job with minimal loss of plastic then restart with brims or rafts.
  • We personally prefer brims over rafts (such as available in Cura and Simplify3D) as they are easy to remove and leave a clean look.
• POST PRINT
  • Other than removing brims/rafts and the occasional drip, there is not any special post-processing required after printing. Some of the big bridges might seem a little saggy but generally speaking there's enough tolerance that this won't cause an issue. The biggest bridges are mostly hidden inside the robot so they won't affect cosmetics.

• OBTAINING THE STL FILES
  • We have posted the STL files to many popular 3D printing model sites such as http://www.thingiverse.com. Search for "Max The Megapod" and they should pop right up.
  • Please note: These parts are considered in pre-release status at this time. Our official release date is currently projected to be October 1. The parts we are posting have been printed many times and tested and do work well for us, but we are making a few more tiny adjustments and refinements.
  • Please help us by rating the Max The Megapod project (or clicking on the LIKE button or equivalent) on whichever site you download it from!
  • Please post your builds to places like Thingiverse, pictures to FaceBook, Instagram, etc., and videos of your robot to YouTube! This will help us grow and continue having the resources creating cool new projects for our community.

Building the Robot

You will need the following tools:

• 2mm hex key. A 5/64 inch hex key will also work. This is in the Megapod Parts bag.
• 7/64 hex key. This is in the Megapod Parts Bag.
• Optional: A marker that can write on dark plastic and still be seen, such as Sharpie Metallic or Sharpie Oil markers (white and yellow work great on dark colored plastic, black or blue work well on light colored plastic). This can be used to make raised lettering on the robot and gamepad more visible.

Step by Step Instructions

• STEP 1: Build the BASE

• STEP 1: Insert accessory port screws in the chassis Insert 5/8" #6-32 hex head screws in the bottom two holes of the accessory port, head of the screw inside the hexapod, then tighten nuts outside. Repeat for the top two accessory holes with shorter 1/2" #6-32 hex head screws. The heads of the screws recess into hexogonal holes so you don't need to use pliers inside the robot body, just for the nuts. Two wingnuts go on the two lower screws, these will be used to secure accessories such as the Joust lance or Capture-the-Flag attachment.

• 

  Be sure to use the hex head screws for the accessory port.

• 

  The accessory port is considered the "front" of the robot.

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  Longer hex head screws go on the bottom. Do not overtighten the nuts.

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  After installing the nuts, put the wingnuts on the bottom screws. They'll be used later to secure accessories.

• STEP 2: Insert servos in the chassis.
  • Next, insert the servo into the chassis as shown in the diagrams below. As you insert the servo into the chassis, slowly press it straight into place until it clicks in under the small tab on one side of the servo holder. Make sure it stays straight as you push down.
  • Immediately mark the black connector at the end of the wire to indicate the servo number (which is engraved in the top of the servo holder, a number between 0 and 5).
    • A metallic sharpie pen works very well for this, or a light colored oil paint sharpie such as white.
    • If you don't have any of those things, a little piece of masking tape can be affixed to the wire and marked, or you could use clear cellophane tape to attach little bits of marked paper to the wire. Do not attach any tape or paper to the black connector, as it will be a tight fit when connecting later.
    • The wire coming out of the servo sticks out away from the robot, the servo shaft would face down toward the table top if the chassis were resting on the table.
  • After inserting the servo, thread the wire through the top servo wire guide hole, and into the center of the chassis.

• STEP 3: Insert the servos in the Legs. The technique is very similar to inserting the servo into the chassis.
  • Insert the servo straight into the leg socket so that the wire is coming out of the servo facing away from the plastic leg and the face of the servo with the shaft and servo horn goes into the open faced side of the leg, as shown in the diagram.
  • The servos in the legs are called the "knee" servos. Each leg has a higher number on it, this is the knee number, they run from 6 to 11. Again, write this number on the black connector at the end of the servo wire. PRO TIP: For 6 and 9, underline the number so you don't read them upside down!

• STEP 4: Thread each leg servo wire into the bottom wire guide slot on the chassis. Each leg servo should be matched with a hip servo plus 6. The legs are marked with the hip number near the top and the knee number below that. For example, the leg marked 6 should be threaded through the wire guide on hip servo 0, leg 7 goes with hip 1, leg 8 goes with hip 2, etc. Add 6 to the hip number to get the leg number.
• STEP 5: Build the electrical system., You need to power up the servos and make them seek to the 90 degree position, this will allow you to adjust the legs properly for walking.
  • STEP 5A: Take the potentiometer and remove the cap, then unscrew the nut and set these items aside for now. Push the potentiometer shaft from the inside of the chassis, into the hole that has the markings "STOP", "TST", etc. The wires coming out of the potentiometer should be pointing down and you may need to bend them a bit to make it all fit. Put the retaining nut on the potentiometer, hand tighten first and then give it just another half turn or so with pliers if desired. Turn the knob all the way counter clockwise, then insert the knob so it points to the letter "O" in the word "STOP".
  • STEP 5B: Take the on/off switch (which is attached to the battery holder assembly) and thread the switch wires through the gap in the switch adapter. Insert the switch and adapter into the switch hole from the inside of the chassis, lining up the holes of the switch adapter with the two matching holes in the chassis. Insert a #6-32 1/2" screw from the outside and turn it to secure one side of the switch, repeat for the other hole. You should put a finger over the hole from the inside of the chassis and apply pressure while screwing in the screw. (See diagrams below.)
  • STEP 5C: Make the connections listed in the ELECTRICAL CONNECTIONS section of these instructions below. Be extremely careful about the power connections. Double check all connections before powering on.

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  Thread the wires through the gap in the adapter

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  Press the switch into the adapter.

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  From the inside of the robot, line up the switch/adapter with the switch hole.

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  While holding the switch/adapter in place, insert screws from the outside of the robot.

The servo horn should come straight out from the body at a 90 degree angle as shown here. Do not turn the servo shaft by hand until after it has moved under power!

• STEP 6: Power up! Make sure the on/off switch is off, and the knob is turned to STOP. Insert batteries and power on the robot using the on/off switch. You should hear a beep, a pause, then a second beep. The servos should all twitch into position. If the robot does not move at all, immediately turn the switch off and check your connections again. If some of the servos don't move (especially any you marked during the servo pre-check) then gently push them with power off to see if you can free them up. If they still won't move, try pushing them with power applied, but turn off the power within 30 seconds if they're locked up. If you can't get the servo to move it will need to be replaced.
• STEP 7: Insert Servo Horns. The servo horns are all at random angles right now due to the servo pre-check. In this step we'll make them point in the right direction. The knee servos are not at 90 degrees when the knob is all the way counter clockwise, rather they are at a 30 degree standing angle. We need to get them to 90 degrees so its easy to align the servo horn. Turn the knob very slightly clockwise and you will see all the knee servos twitch. This is "adjust servo horn mode". All servos (knees and hips) are now at their halfway point, 90 degrees. Now you need to take each single arm servo horn and carefully insert it on the shaft so that it is sticking straight out as shown in the figure. You will not always be able to make the horn come totally straight out. This is because there are only 22 little groves (splines) in each shaft, meaning you can in general only come within about 8 degrees of being at a perfect 90 degree angle. This amount of error is acceptable, just get it as close as you can. It is better for the horn to be a little too much clockwise than to be a little too much counterclockwise, especially for the knees. Do this for all hip and knee servos. Do not insert any screws yet.

Align the leg hinges as shown here. The bumps (see arrows) should both be near each other when properly aligned. Hold one in each hand with the ends of the U shape between thumb and forefinger.

• STEP 8: Assemble the leg hinges. Each leg hinge is composed of two identical U-shaped parts. Take one in each hand and align the two so that the bump (shown in the diagram at the right) are both near each other. Turn one 90 degrees with respect to the other.
  • Gently squeeze each piece between thumb and forefinger, which causes the little jaws in the center to open up slightly. Work the two halves together. Squeeze just enough so they work their way on, no more or you might break the part!.
  • At this stage, you may notice that the parts are loosely clamped on each other. Don't worry! When you place the leg hinges over a servo, the servo will spread it apart and they will lock together tightly.
• STEP 9: Attach Leg Hinges. The leg hinges connect the hips to the knees. They only go on one way. First place the end that matches the servo horn on, then you need to very slightly bend the U shaped piece while pulling it over the hemispherical bearing on the other side. It's a little easier to do the knees (servos mounted to legs) first, followed by the hips (servos on base).
  • NOTE: It should not be excessively difficult to push the hinge over the hemispherical bearing. If you find you are struggling, that means the hinges are too tight. This may affect walking. This can be due to the kind of plastic you used or how your printer is adjusted. You may need to gently spread the two legs of the U shape by hand before putting the hinge on the robot. Be careful of course not to break the hinge.
• STEP 10: Test Knee Positions. Turn the knob fully counter clockwise (to STOP) and the robot will go into "stand still" mode. Place it on a level surface such as a table top. Do all of the legs touch the ground? If one or more legs don't touch the ground, you need to adjust the servo horn on the knee a little bit so it does touch. Gently pull off the servo bracket. Pull the servo horn off, and put it back on just a little bit moved so the leg would move closer to the ground. Put the servo bracket back on, and see how it looks. Do this until all legs are at least slightly touching the ground. Again, you can't necessarily be perfect due to the 8 degree increments the servo horns can be moved. But you should be able to be close enough that all legs at least slightly touch the ground.
• STEP 11: Insert Servo Screws. Now that the legs are adjusted, you can insert the M2.5x8 screws into the servo horns to lock them in place. Note that you will NOT be using the screws that were in the little bag the servos came in, you'll be using the separate pack of screws, which are longer than the ones in the servo bag. Do not overtighten these screws, as you could possibly crack the servo brackets. Just turn the screws until you start to feel resistance, then turn a quarter turn more and stop.
• STEP 12: Test Individual Servos. To test whether every servo is working, put the robot on its stand. Then start with the knob on STOP, then slowly turn it clockwise. First the servos will go into adjust mode, you used that a moment ago to set the servo horns. But, keep going, and the robot will go into "individual servo test mode". In this mode, every hip servo will move, one by one. When all the hips have moved, every leg will move, one by one. You should see every servo move, in order. If some don't move, check your connections. A common error is to plug a servo connector into the servo controller backwards (i.e. the brown wire is matched with the yellow pin instead of the black pin).

• STEP 13: Test Using Demo Mode. Ok, everything looks good, so time for a full test. Turn the knob to STOP, then take the robot off the stand and put it on the floor. Turn the knob to DEMO, and the robot will go through a series of movements to demonstrate some of the things it can do. The full demo only takes about 30 seconds, then repeats. Here, you are looking for the robot to, for example, be able to get back up off the floor after doing some of its dance moves. If the robot struggles to get off the floor, you may have a battery that is not fully charged, or there may be too much friction between the servo bracket and the little ball socket it sits in. A tiny bit of silicone lubricant will usually fix that problem, or just make sure those parts are cleaned up from 3D printing and don't have an excess strands of material that are causing friction. See the Trouble Shooting Guide for more information about different kinds of issues that can occur.
• STEP 14: Store the Electronics in the Caddy Now things look pretty messy with all those wires hanging loose, let's clean it up by stowing them in the electronics caddy. Please reference the video and diagrams here for quick instructions.
  • STEP 14A: Insert Caddy Bars Insert the two electronics caddy bars as shown in the diagrams below. Notice carefully how they are inserted. You may need to slightly squeeze the forked section at the end to work it into the hole. Once inside, it may be difficult to remove because it will snap into place, so be sure you're putting it in the right way.

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  Here one bar has already been inserted, the other is being put into place. Notice the orientation, don't put it in upside down. The little nubs at the end should be facing the caddy.

• • STEP 14B: Insert the Servo Controller and Arduino Nano The diagrams here do not show the wires to make them easier to visualize. Carefully insert the servo controller as shown, making sure you don't pull out any of the wires. You may need to wiggle the electronics caddy bar from side to side a bit so that components can slide past it during insertion. Notice that the end of the Servo controller with wires sticking out of it must go in last. Carefully insert the Arduino Nano as shown, making sure you don't pull out any of the wires. You may need to wiggle the electronics caddy bar from side to side a bit so that components can slide past it during insertion. Notice that the end of the Nano that has the USB port must go in last.

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  Insert the servo controller so it is sandwiched between the bar and the electronics caddy. Wires not shown for clarity.

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  Insert the Nano so that the USB port faces out away from the electronics caddy, this allows you to access it without disassembling the robot.

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  This is what the underside of the electronics caddy looks like after inserting the Servo Controller and Arduino Nano. Wires not shown for clarity.

• • STEP 14C: Insert the HC05 Bluetooth Module The diagrams here do not show the wires to make them easier to visualize. The HC05 Bluetooth module with a name beginning with "S" should be used for the robot. For example, the label will read something like "VORP S2944" (the number will differ). The one marked "M" will be used for the gamepad. Slide the HC05 into the side drawer as shown. When inserting, be careful not to pull out the wires, which will be a little tight. Work the wires into the little space provided so they stay clear of the robot's cap when it gets screwed on later.

• 

  Insert the HC05 into the side drawer as shown.

• 

  When fully inserted, the indicator light will still be visible through the small oval. The wires should be tucked into the little cavity near the pins of the HC05.

• STEP 15: Assemble the Cap
  • STEP 15A: Put magnets in the Cap Insert a magnet in each magnet holder in the cap. The magnets are marked with a dimple on the North pole side. It is important that this dimple be showing after installation. In other words, insert the magnet with the non-dimple side down. Pressing with just your fingers might work, but if the magnet does not complete seat, use pliers to gently squeeze it into place. Be careful because if you squeeze too hard you might crack the Cap.
  • STEP 15B: Decorate If desired, use a permanent marker to color the Vorpal "V" on top of the Cap. Oil markers work well. On light colors of plastic a black permanent marker will also work.
  • STEP 15C: Put Cap on the Hexapod Screw the cap on the robot by lining up the tabs with the matching slots in the rim of the base. Turn the cap clockwise to lock it in place. IMPORTANT: Do not press down on the robot to insert the cap when the robot is under power standing on its legs! You can damage the leg motors by doing this. It is best to turn the robot off, and either support the bottom of the Base with one hand and press the Cap on with the other, or set the Base down on the table top or floor with legs out to the sides so they don't take pressure.
• STEP 16: Warning Label There are two a self-stick choking hazard warning labels in the hexapod parts bag. Peel the backing off one of them and place it on the bottom of the robot, near the center. Retain the second label for the gamepad.

Building the Gamepad

The gamepad for Max The Megapod is identical to the Gamepad for Vorpal The Hexapod.

Please see instructions on the Vorpal Hexapod Assembly page.

Trimming the Servos

When you assembled the servo horns onto the servos, you probably were not able to get them all to come out exactly at a 90 degree angle. That's not your fault: the servo horns only have 22 possible positions in which they can be installed, so at best you can come within plus or minus 8 degrees of perfection.

Now that you have the gamepad working, you can make fine adjustments to the servo positions using "Trim Mode". In this special gamepad mode, you can adjust all the servos. These adjustments are saved in the robot's EEPROM, which is memory on the Nano that retains data even when powered off. So, you only need to trim once.

Complete instructions on how to use trim mode are in the wiki page: Vorpal The Hexapod Trim Mode Guide.

NOTE: although this step is optional, it is recommended because your robot will walk straighter and all the servos will share equally in lifting the robot's weight, which will make them last longer.

Assembling Eye Decorations

Glue a magnet into the magnet hole on both sets of eyes. The magnet should have the marked side face down, not showing.

You can use hot glue, "superglue" or any other kind of glue that works on plastic and metal.

Electrical Connections: Robot

NOTE: These are the official RELEASE 1 connections. If you have an older prototype (you can tell because the gamepad has no SD card reader in the older version) then please see Vorpal Combat Hexapod Prototype Electrical Connections.

NOTES ON JUMPER WIRES

Wire Lengths

There are two different lengths of female-female Dupont jumper wires used to make most connections. The longer ones (20cm) are only used for the Hexapod's accessory port connections. The shorter ones are used for all the connections on the Gamepad and all the connections on the Hexapod between the Arduino Nano, Servo controller and Bluetooth module.

Wire Color Conventions

Please follow these conventions when selecting wire colors:

• For +5V, Vin, and similar positive voltage connections, use either RED or ORANGE.
• For GND and other negative electrical connections, use BLACK or BROWN.
• For the connectors that sit at the mouth of the accessory port (used for optional sensors) colors are suggested below in the instructions. By following these suggestions you will make your life easier when connecting sensors!
• For all other connections, you can use any color you want, it's arbitrary.

If Jumper Wires Are Too Loose

Sometimes you will find a wire whose connector does not grip the pin well enough. It might fall off very easily or just by gravity alone. If that happens, you have a few options:

• There are extra wires in your kit. If you find a wire that's too loose, just use a different wire.
• Using the hex key, you can put the jumper housing on a flat surface then press on the metal showing through the plastic connector, which will tighten up the jumper wire's grip. Don't go too overboard on pressing though or you might make it too hard to insert.
• Alternatively, you could use electrical tape after inserting all the wires on a module (such as the Nano) to effectively attach together all the little plastic female connector housings. In that way, the connectors that do grip will help hold in the ones that are too loose. Some people also like using hot glue for this purpose. (Personally, I don't like using hot glue, as it makes it harder to change connections if you hooked something up incorrectly.)

NANO PIN CONNECTIONS

Diagram of Nano connections for the Hexapod. Jumpers marked AP are routed to the Accessory Port for use with add-ons like sensors. Click for larger image.

• Digital IO Pins:
  • D0, D1 are reserved because they are used for uploading programs to the robot, so nothing will be connected there.
  • D2 Bluetooth Module Rx
  • D3 Bluetooth Module Tx
  • D4 Buzzer Signal (white wire)
  • D5, D6 NO CONNECTION. These pins are reserved for future expansion.
  • D7 20cm GREEN Dupont connector routed to accessory port, used for Ultrasonic Rangefinder TRIG
  • D8 20cm BLUE Dupont connector routed to accessory port, used for Ultrasonic Rangefinder ECHO
  • D9 No connection. This pin is reserved for future expansion.
  • D10 through D13 are reserved for the optional CMUCAM5 (Pixie) sensor accessory.

• Analog Pins:
  • A0 Potentiometer signal (white wire)
  • A1 Potentiometer Power (red wire)
  • A2 Potentiometer Ground (black wire)
  • A3 20cm YELLOW Dupont connector routed to the accessory port, for the optional light sensor or other analog sensors.
  • A4 Servo Controller SDA
  • A5 Servo Controller SCL
  • A6 20cm PURPLE Dupont connector, routed to the accessory port, for any analog sensor you wish to optionally add later.
  • A7 No connection, reserved for future use.

• Power Pins:
  • VIN pin on Nano connects to Battery positive (the red Dupont connector coming off near the switch on the wiring module)
  • GND pin on Nano connects to Battery negative (the black Dupont connector coming off the battery black wire)
  • Second GND pin on Nano (there are two GND pins on the Nano) connects to the GND pin on the HC05 module
  • +5V on Nano connects to HC05 +5V Pin

IMPORTANT NOTE: The red Dupont connector coming off the switch/battery assembly must go to VIN and never +5V, because the battery voltage is much higher than +5 volts. You will more or less instantly destroy your Nano if you put unregulated battery power directly into the +5V pin. The VIN pin has its own voltage regulator. The +5V pin on the Nano will be used to provide regulated power to the Bluetooth module.

Bluetooth Module Power

• +5V on HC05 connects to Nano +5V pin
• GND on HC05 connects to either of the two Nano GND pins

Buzzer Power

• Connect the buzzer V+ and ground (marked "-") pins (red and black respectively) to Port 13 of the Servo Controller, matching black and red wires to black and red pins on the Servo Controller. You will be using the special three wire cable provided for this purpose. It has a three-pin connector one one side, and the other side has a two-pin connector and a one-pin connector. The one-pin connector goes to the Nano and provides the signal to drive the buzzer. The two-pin connector is plugged into Servo Controller Port 13.

Servo Controller

Diagram of Servo Controller pins you will use in this project. Each servo motor has a 3 wire connector. Match the brown servo wire with the black color coded pin in its servo port, match the yellow wire with the yellow pin. Click for larger image.

• Connect the 12 servos to port numbers corresponding to the servo marking (0 to 11). Make sure the signal wire (yellow) is oriented correctly and matches the yellow plastic header pin.
• Connect the switch/battery module regulated BEC output (a three pin Dupont connector where only two of the pins are populated, one with a red V+ wire, one with a black ground wire) to servo controller port 12 power and ground. Make sure the RED wire is going to VCC (red pin) and the BLACK wire goes to GND (black pin).
• On one short side of the Servo Controller you will find a VCC and V+ pin right next to each other. Use a shunt (small black connector that goes over two pins) to connect those together if one is not already installed. This shunt causes both the servos and the microprocessor to run at the same +5V level.
• SDA and SCL go to A4 and A5 on the Nano, respectively.
• Servo port 12 RED and BLACK pins are connected to the output of the BEC. Make sure the BEC RED wire matches with the RED pin, and the BEC BALCK wire matches with the BLACK pin.
• Servo port 13 RED and BLACK pins are connected to the passive buzzer power connector. Make sure the buzzer BLACK wire matches the BLACK pin, and the RED wire matches the RED pin.
• Servo port 14 RED pin goes to a 20cm ORANGE Dupont connector and is routed to the accessory port to provide +5V for sensors or other accessories.
• Servo port 14 BLACK pin goes to a 20cm BROWN Dupont connector and is routed to the accessory port to provide GND for sensors or other accessories.
• Servo port 15 RED terminal goes to a 20cm RED Dupont connector and is routed to the accessory port to provide +5V for sensors or other accessories.
• Servo port 15 BLACK terminal goes to 20cm BLACK Dupont connector and is routed to the accessory port to provide ground for sensors or other accessories.
• Servo port 15 signal terminal goes to 20cm WHITE Dupont connector and is routed to the accessory port to provide signal for a servo used in an optional accessory.

Accessory Port Wire Bundle

The 20cm wires connected to the Nano and Servo Controller provide access to digital ports, analog ports, and power for accessories such as sensors, lights, or other projects. These wires should be bundled up near their unconnected ends (a rubber band works well for keeping them all together) and routed to the large opening below the accessory port hex head screws on the chassis. When there is no accessory in use, these wires can remain tucked inside the accessory port. When needed, pull them out a few inches and connect to sensors or other electrical accessories.

Connecting the HC-SR04 Ultrasonic Rangefinder to the Accessory Port

When building the robot you routed longer jumper wires (20cm) to the accessory port. You need four of these wires to use the Ultrasonic Rangefinder:

• RED accessory port wire goes to HC-SR04 VCC
• BLACK accessory port wire goes to HC-SR04 GND
• GREEN accessor port wire goes to HC-SR04 TRIG
• BLUE accessory port wire goes to HC-SR04 ECHO

Connecting the Light Sensor (or any Arduino compatible 5 volt analog sensor)

• RED or ORANGE accessory port wire goes to Vcc (may also be marked +5V or Vin) on the sensor
• BLACK or BROWN accessory port wire goes to GND on the sensor
• YELLOW (A3) accessory port wire goes to the Signal pin on the sensor. This may be marked different things on different sensors.
  • You may also use PURPLE (A6) for a sensor (or a second sensor)
  • The Scratch Sensor block allows you to choose A3 or A6 sensor ports.

A note on how many things can be connected through the accessory port

We are providing two sets of power connectors at the accessory port for sensors or other accessories. RED/BLACK and ORANGE/BROWN each respectively provide +5V/GND. It's up to you what things you want to connect using these. You could have one or two sensors, you could have a sensor and some kind off motorized accessory. You could have a sensor and an LED light strip, etc.

Nothing is stopping you from creating a Y connector to make additional power connections, except that there is a limit of 3 amps of current that you can pull from the battery/BEC system. The robot itself needs up to 2.5 amps during fast motions. But many sensors can operate on just a few milliamps. Adding a motorized accessory is where you would need to be careful about how much current you're pulling from the system. If you pull too much current, typically the BEC will overheat and go into thermal protection mode, which will shut down all the motors until you reboot the robot. It is possible to use a mini servo under moderate load for a motorized accessory, but a full sized servo under heavy load might be too much. Use caution when designing your own accessories, especially if they are going to use more than a few hundred milliamps of current.

Robot Screw Sizes

• Servo horn screws: 12 x M2.5 by 8mm long
• Switch assembly: 2 x #6-32 by 1/2" long

Electrical Connectons: Gamepad

Note: These connections are for the Kickstarter Release 1 product. If you have an older prototype (the gamepad does not have an SD card reader in the prototype) then please see Vorpal Combat Hexapod Prototype Electrical Connections.

GAMEPAD NANO PIN CONNECTIONS

Diagram of Nano connections for the Gamepad. Click for larger image.

• D2 through D9 are connected to the button matrix pins.Looking from the top of the button matrix module, the rightmost button matrix pin (labeled 1) goes to D9, second to right (labeled 2) to D8, etc.
• D10 to SD card CS (may be labelled SS on some SD card readers)
• D11 to SD card MOSI
• D12 to SD card MISO
• D13 to SD card SCK (may be labelled SCL on some SD card readers)

• A0 Unused
• A1 Dpad OUT (white wire)
• A2 Dpad VCC (red wire)
• A3 Dpad GND (black wire)
• A4 HC05 Bluetooth Module Rx
• A5 HC05 Bluetooth Module Tx
• A6, A7 Unused

• VIN battery/switch positive (red wire)
• GND Either ground on the Nano goes to the battery/switch negative (black wire)
• ICSP pin 4 (see diagram): SD card reader GND
• ICSP pin 6 (see diagram): SD card reader VCC
• Nano +5V pin goes to HC05 +5V pin
• Nano GND pin (there are two, you can use either one) goes to HCO5 GND pin

GAMEPAD: Screw Sizes

• Switch assembly, 2 x #6-32 by 1/2" long
• Gamepad Cover, 4 x #6-32 by 1/2" long

Max The Megapod Quick Links

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