Introduction: DiddyBorg: the Mini 6 Wheeled Raspberry Pi Robot!
DiddyBorg is our robust robot kit for the Raspberry Pi. He can be controlled via autonomous software, via a Bluetooth controller such as the PS3 or over Wifi through a keyboard. Check out this video of him rolling around!
This Instructables is concerned with the building of the hardware. There is some software preparation which should be done with the Raspeberry Pi before continuing as the HDMI slot becomes difficult to access once the Raspberry Pi is in the chassis. Head over to this page to prepare your Pi.
To build your DiddyBorg you will need:
- DiddyBorg kit
- Raspberry Pi with SD card
- 10 AA batteries (we recommend rechargables)
- Soldering Iron and solder.
- Flat bladed screwdriver.
- Wire cutters
- Adjustable spanner.
Step 1: Prepare Your Perspex
Peel white plastic protection layer from Perspex and gently clean all perspex parts with a soft cloth such as a leather chamois or a glasses cloth and clean water. Some marks may be left by the Laser cutter.
If these are particularly hard to shift, a small amount of very weak IPA solution or whiteboard cleaner can be used. Do not use too much or you may damage the perspex.
Step 2: Place Screws and Washers Into the Motor Mounts.
Place 4 of the M3x12mm Cheese screws and 4 of the M3 Spring washers into each of the 4 motor mounts to be placed at the corners of the chassis. Make sure the orientation of the motor mount is as per the picture.
Please note the kit contains M3x12mm and M3x8mm Cheese screws. Make sure you have the longer screws for this step.
Step 3: Place Your Motor Mounts on to the Perspex
Take the base board (the one without the PiBorg logo) and orient it so that the short thick rectangular cut out is at the top left, as in the picture. Place the motor mount on top, with the rounded edge facing up, and locate the four screws in the holes of the perspex.
Step 4: Attach Your Motor Mounts to the Base Board
Hold the screws in with your finger tips, and flip the board over.
Place a M3x40mm Black Nylon post on the screw which is closest to the corner of the Perspex board. Tighten this gently with your fingers. We will tighten this correctly later.
Step 5: Add Spring Washers and Bolts to the Remaining Screws
Place 3 of the M3 Spring washers and 3 of the M3 Lock nuts on the remaining screws, and tighten gently with your fingers.
Step 6: Attach a Middle Motor Mount
Do the same for the middle motor mount. Using 4 of the M3x12mm screws and 4 of the M3 spring washers on one side, but on the opposite side use 2 of the M3x40mm Black Nylon posts on the two holes towards the outside edge of the Perspex.
Do not use a spring washer with the posts. Place 2 of the M3 lock nuts on the remaining screws.
Step 7: Complete for the Remaining Motor Mounts.
Repeat the previous two steps for the remaining motor mounts.
Step 8: Align the Motor Mounts.
Position the mounts so that they are all in a line.
Once the alignment is correct, tighten the Nylon posts gently by hand. Be careful not to overtighten, or you could strip the thread from the Nylon post. We just need to tighten to the point where we have crushed the spring washer underneath so it is flat.
Step 9: Tighten the Nuts on the Motor Mounts
Tighten the lock nuts and screws using a flat bladed screw driver and an adjustable spanner or a 5.5mm socket.
Do not over-tighten or you may crack the perspex. Again, tighten just to the point where the spring washers are flat.
Turn your board to that the posts are pointing upwards.
Step 10: Mounting Posts for Your Raspberry Pi
Place 3 of the shorter M3x10mm black posts in the holes as shown in the image. They should be oriented so the post are on the opposite side to the longer posts on the motor mounts.
Gently tighten the M3x10mm black posts with 3 of the M3 Black Nylon nuts on the side facing upwards.
Your Raspberry Pi will have different mounting holes dependent on which variety you have.
- If you have a Raspberry Pi model A+ or B+, place 4 of the M2.5x10mm white posts in the four holes as shown in the top B+ diagram. Add 4 of the M2.5 Nuts.
- If you have a model A or B Rev 2, place 2 of the M2.5x10 white posts in the two holes shown in the bottom diagram labelled B. Add the 2 of the M2.5 Nuts.
Once you have attached your mounting posts for your Raspberry Pi, flip your base over so that the longer posts are pointing downwards, and your motor mounts are pointing upwards.
Step 11: Adding the 6 Motors
For each motor you will need 2 of the M3x8mm Cheese screws and 2 of the M3 Spring washers.
Place the motor in the mount and align the motor holes with the mount. Insert the screws and washers and tighten into the motor until the spring washers have compressed.
Note the motors are all facing the same way; with the stickers facing upwards. This keeps the polarity of the motor connections consistent which will be helpful later.
Reapeat with the remaining 5 motors.
Step 12: Fit the Motor Grub Screws
Take a Motor Hub and a Motor grub screw.
Use the Allen key in the motor kit to put the grub screw in the hub. It should go in freely, do not use force or it may be cross threaded. If it feels like it is tight to screw in, loosen completely and try again. The motor has a detent or "flat" surface ground into the shaft.
This should be aligned with the grub screw so the screw is perpendicular to the flat surface.
Align the hub so that a small amount of the flat is visible and tighten. Add the second grub screw to the under side of the hub and moderately tighten.
Step 13: Fitting the PicoBorg Reverse
Place the PicoBorg Reverse on the black posts and attach with 2 of the M3 Black Screws.
Place 2 of the M3 white washers from the BattBorg post kit over the remaining hole and add an M3x10mm black post from the same kit. Tighten gently.
Step 14: Wiring Up the First Motor
The next few steps will show how to connect the PicoBorg Reverse up to the motors, take your time here as there are 12 connections to make and it will cause confusion later if this isn't correct.
Take the red wire, and strip approximately 3mm of insulation from the wire. The easiest way to do this is with a wire stripper. If you use pliers or scissors, make sure you do not damage the conductor.
First connect up the motor furthest from the PicoBorg Reverse. The motor has a red dot next to the positive terminal. This is where we will connect the red wire. Place the exposed conductor through the positive terminal.
Make the wire follow the path to the M2+ connector on the PicoBorg Reverse. This is the connector furthest from the center. The wire should not be too slack or too tight. See the picture for a good indication of how much slack to give.
Once lined up correctly, cut the cable approximately 10-15mm beyond the edge of the board.
Solder the positive connection to the motor. Be careful not to drip or spray solder on to the Perspex (a small piece of cardboard or similar is useful to protect the Perspex here). If you are new to soldering, it's a good idea to have someone help you.
Step 15: Wiring the Rest of One Side With the Red Wires
Repeat the previous step for the other two motors on the same side.
Unscrew the connector so that the connector slot is opened up. Place all three conductors in the M2+ connector.
Ensure they are in as deep as they will go, and tighten. If the Red insulator is being 'bitten' by the clamp, you will need to strip slightly more insulator off the cable. If there is too much conductor exposed, trim the ends off the conductor slightly. The picture give a good indication of the ideal amount to expose when connecting the red wires.
Once tightened, gently pull on each individual cable to ensure it has been properly 'bitten' by the clamp of the screw connector. If not, release connector and try again.
Step 16: Wiring the Same 3 Motors on One Side With the Black Wires.
Take a black wire and route it to the remaining connector on the motor. This will go to the terminal M2- on the PicoBorg Reverse.
Solder the wire to the motor on the connector next to the red wire and strip the black wire at the PicoBorg Reverse connector as in the previous 2 steps.
Repeat for all motors on the same side as the motors with red wires.
Step 17: Wiring the Remaining 3 Motors With Red Wires
Take the red wires again and repeat the red wire connections for the remaining 3 motors on the opposite site - red wire to red dot on the motor, but this time connect them to the M1+ on the PicoBorg Reverse.
Solder the wires connected to the motors. Tighten these three red connections in to M1+.
Step 18: Wiring the Remaining 3 Motors With Black Wires
Take the black wire again, and connect the three remaining motor connections to M1- on the PicoBorg Reverse. Solder the wires to the connections on the motors and tighten the M1- connector on the PicoBorg Reverse.
You have now completed the wiring on DiddyBorg for the PicoBorg Reverse. The pictures show how the wiring should look from different angles, so take a moment to check it is correct.
Step 19: Wiring the BattBorg
Take the BattBorg, strip approximately 8mm from the ends of the red and black wires, insert into the BattBorg and tighten. Ensure the connectors are gripping the conductor, not the insulator. It is important here that the insulator is not too long, as it could potentially short to the motor, or to each other.
Once tightened, gently pull on each individual cable to ensure it has been properly bitten by the clamp of the screw connector. If not, release connector and try again. Bend the cables towards the silver panel and between the two layers of the PCB.
Step 20: Adding BattBorg to DiddyBorg
Plug the BattBorg into the PicoBorg Reverse. Ensure the 6 pin connector on the BattBorg is directly over the 6 pins on the PicoBorg Reverse. The screw hole in the BattBorg should roughly align with the black post.
Screw in the M3 Black Screw from the BattBorg post kit. Ensure again that the V+ and GND cables are not shorting on the motor, on each other or the silver pad on the BattBorg PCB.
Step 21: Routing Wires From the BattBorg to the PicoBorg
Route the Red and Black wire from the BattBorg to the V+ and GND connectors on the PicoBorg Reverse with a small amount of excess wire. Trim the cable to approx 10-15mm beyond the connectors. Strip approx 8mm from the cable ends.
Step 22: Adding the Battery Strap
Take the 9V battery strap and place it through the hole in the center of the base from the long post side to the motor side.
Step 23: Connecting the Battery Strap and BattBorg to the PicoBorg
Connect both the red BattBorg wire, and the red 9V battery strap wire to the V+ terminal on the PicoBorg Reverse.
Connect the black BattBorg wire and the black 9V battery strap wire to the GND connection on the PicoBorg Reverse. Tighten both screws and pull gently to ensure the connector clamp has bitten.
Ensure again that the insulator and conductor lengths are correct.
Step 24: Mount Your Raspberry Pi
Place the Raspberry Pi (with it's memory card already installed) over the clear posts. The GPIO pins of the Raspberry Pi should be towards the center of the assembly.
- Add 4 of the M2.5 Screws for the model A+/B+.
- Add 2 of the M2.5 Screws if you have a model A/B.
Step 25: Connecting the First Cable From the Raspberry Pi to the PicoBorg Reverse
Take one of the PicoBorg Reverse Comms cables and pass it through the comms hole in the perspex base. Orient the cable so that the white cable is on the side of the middle motor.
Turn the base so that the PicoBorg Reverse is facing up.
Plug the cable into the back 3 pins of the 6 pin connector on the PicoBorg Reverse. This is white on Pin 2.
Flip the base so that the Raspberry Pi is facing up.
Plug the connector in so the white pin is also in Pin 2.
Step 26: Connecting the Second Cable From the Raspberry Pi to the PicoBorg Reverse
Take the other PicoBorg Reverse Comms cables and connect the white to Pin1 of the Raspberry Pi
Pass the comms cable through the hole in the Perspex next to the other cable.
Connect the other end to Pin1 of the PicoBorg Reverse.
Double Check connections Pin1 to Pin1 and Pin2 to Pin2.
Step 27: Fitting Wheels to the Motors
Hold the motor that you are adding the wheel to with one hand and the wheel in the other. Align the hexagonal patterns on the wheel and hub, and with a very small amount of pressure, push the wheel onto the hub.
Take an M4x5 Cheese screw and screw it into the hub to hold the wheel in. Be careful not to cross thread. If it feels like it is hard to screw them on, unscrew and try again.
Repeat for the remaining 5 wheels.
Step 28: Fitting the Raspberry Pi Camera
If you have a Raspberry Pi camera to add to your DiddyBorg, take the perspex camera holder and add 2 of the M2x8mm Nylon screws to the center two holes. Also add 2 of the M2 washers to the inside of the camera holder.
Add the Raspberry Pi camera to the camera mount. It should be aligned with the box cut out and the bottom two holes. We will only use the center two holes here.
Carefully place the M2 Nuts on the back of the camera. Tighten gently. The board should not flex. if it does, ensure you have the washers on the correct side.
Place the camera on its mount into the perspex base with the cable side pointing upwards. Plug the camera cable into the Raspberry Pi as per Raspberry Pi foundations instructions.
Note It should not be difficult to slot the perspex camera mount in to the base. If it is, check alignment carefully. The camera module should be a snug fit to minimise vibrations, but if it will not sit in the mounting holes, removing the edges of the perspex will help. You can do this with fine ~600 grit wet and dry sandpaper. It should only require a small amount of sanding. Remove the camera module before sanding!
Also, if you do not have a Raspberry Pi camera you can choose if you want to install the perspex camera holder or not.
Step 29: Installing the Battery Holder
Insert 10x AA batteries into the battery holder. We recommend rechargeable batteries. All the batteries should be the same type and age. Be careful not to short out the contacts on anything metal once they are installed.
Place the reusable cable tie through the battery slot in the perspex, between the motor cables and the Perpex, then back up through the other battery slot. Also ensure the 9V battery strap is pulled taught, and is sitting over the back of the assembly.
Place the battery pack between the cable tie and between the motor mount screw ends in both vertical and horizontal directions. The four edges of the battery pack should sit against the lock nuts of these screws. Thread the cable tie end through the zip end opening.
Tighten the cable tie, and bend the end of the tie so it doesn't point straight up. Over time this will naturally bend, but initially it will be difficult to put the top on in the next step.
If you are struggling to get the battery pack to fit, you can rotate the battery pack to fit in from front to back rather than side to side orientation (see last picture in this step)This. This also allows for a slightly longer extension of the 9V connector.
Step 30: Putting the Top On
Place the perspex top on the long bolts and camera assembly (if used). Hold the camera assembly with one hand and align to the cut outs in the top. There may be a small amount of force put on the posts to align the holes and post threads.
Whilst maintaining a small amount of pressure on the perspex top, screw on the remaining 8 M3 Black Nylon nuts.
Step 31: Finishing the Build!
We are just about ready to go!
It's a good idea at this point to visually inspect the wiring, double check connections and polarity before powering on.
When you are happy all is correct, ensure the correct direction of the battery pack connector and plug in.
Start playing! Head over to our website for more software for DiddyBorg. Let us know how you are doing on our Forum or on Twitter!
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