Assembling the Duckiebot

Preliminary Steps

Modified 2018-09-04 by Gianmarco Bernasconi

Step A

Unbox all of your components, and lay them out on a flat surface. Ensure that you have well lit, uncluttered space to work on.

Although not necessary, you might find useful getting a small (M2.5) wrench to ease some of the passages.

Step B

Take the rear bumper bracers and the back bumper. The back bumper will be mounted in the last steps as a press fit to the rear bumper bracers. Try to fit the bracers into the holes of the back bumper.

Some bumper bracers have a plastic protective film which is a residue of the manufacturing process. If you struggle in the press fitting, peel off the plastic cover from one side of the bracer. If this does not help, peel off the plastic cover from both sides.

Step C

Peel the plastic cover from all the chassis parts (except the bumper bracers) on both sides.

Step D

Note that a few among all of your metal screws are special. They are “countersunk” screws. Keep these aside. They will be needed in Part 15: Back bumper assembly.

Step E

Every time you read M3x8 screw, a M3x10 will do the same trick. You can exchange them at will.

Do not exchange metal and nylon screws though. The latter are not electrically conductive and are passive protections to potential short circuits that can damage your Duckiebot beyond repair. This is especially true for Part 4: Assemble Onmi-directional wheel and bottom chassis; make sure you use the correct nylon screws at that step.

Remember that instructions are your friend! At least at this stage, try to follow them precisely.

If regardless of this foreword you still choose to try and figure it out yourself, it’s ok, but for the love of what is precious, do not plug the battery in until you have performed a visual inspection Subsection 4.16.1 - Step 1: Visual inspection.

Step 1

Modified 2018-11-07 by tanij

Pass two of the motor holders through the openings in the bottom plate of the chassis as shown in Figure 4.8. If you have troubles fitting the holders, it is probably because you have not removed the protective plastic film.

Step 2

Modified 2018-11-07 by tanij

Put one motor between the holders as shown in Figure 4.10.

Step 3

Modified 2018-11-07 by tanij

Use 2 M3x30 screws and 2 M3 nuts to secure the motor to the motor holders. Pass the screws through the holes from the outside inwards, then tighten the screws to secure the holders to the bottom plate of the chassis as shown in Figure 4.12.

Step 4

Modified 2018-11-07 by tanij

Repeat for the opposite side and check that the outcome is the same as in Figure 4.14.

Step 5

Modified 2018-11-07 by tanij

Tilt your bottom plate and pass the cables of the motors through the central hole. Keep the cables coming from each motor separated (Figure 4.16).

Step 1

Secure the M3x25 spacers to the omni-directional wheel using 2 M3 screws (M6 to M10 will work, choose the shortest you have in your pack) as shown in Figure 4.20.

Step 1

Pass the screws through the designated holes from the top, as shown in Figure 4.24

Step 2

In the bottom part, secure the omni-directional wheel using the screws.

Check the outcome

Modified 2018-11-07 by tanij

Figure 4.26 shows how the omni-directional wheel should be attached to the plate.

Step 1

Insert two M3x8 screws in the designated holes and place the rear bumper on them, they should align as in Figure 4.30. A little forcing might be necessary.

Step 2

Fasten the bottom rear bumper bracer using the M3x25 standoffs (shorter ones), then use the M3x30 standoffs (longer ones) for the front of the Duckiebot. The result should look like Figure 4.32.

Step 1

Insert one wheel on each motor, as in Figure 4.36. Mind that there is a particular orientation at which the wheel will fit. Don’t force them too much!

Check the outcome

Figure 4.38 shows how the assembly should look like after mounting the wheels.

Step 1

Peel the cover from the bottom of the heat sink and place it on the Raspberry Pi microchip, as shown in Figure 4.42

Step 2

Locate the camera cable plug (see Figure 4.44 for reference) in the Raspberry Pi and lift the black “wings” to open it.

Step 3

Make sure that the connectors of the camera cable match the ones in the Raspberry Pi (Figure 4.46), then plug in the cable and push down the black wings to fasten the connection, making sure it “clicks”.

Step 4

Find the SD card holder on the Raspberry Pi (on the bottom of it). Then insert the micro SD card as in Figure 4.48. Note that SD cards might vary in appearance, the figure is just for reference.

Check the outcome

Figure 4.50 shows how the Raspberry Pi should look like now.

Step 1

Place the spacers on the bottom part of the Duckiebot hut, as in Figure 4.54

Step 2

From the top of the Duckiebot Hut, secure using the M2.5 nylon nuts.

Step 3

Place the Raspberry Pi as in Figure 4.56, passing the camera cable through the slit in the Duckiebot Hut. Then plug in the Hut, by making sure that the Raspberry Pi GPIO pins fit into the Hut connector.

Repetita iuvant: visually inspect the Hut’s GPIO pins and make sure they do not touch each other (i.e., are straight).

Step 4

Take one of the two sets of F/F jumper cables, and attach it to the Duckietown Hut as shown in Figure 4.58. It is important to use the pins named: “5Vusb, ADR LED and GND”, do not use the pin labelled “5Vraspi”. Take note of which color have you connected to each pin.

Step 5

Finally, attach the two USB cable to the power plugs, as in Figure 4.60. Note that the color of the USB cables might vary, so don’t worry if yours are not exactly as those shown in the picture below. The two USB cables could also be uncomfortably short. If your powerbank/battery comes with longer cables you might want to use them instead.

Check the outcome

Figure 4.62 shows how the Raspberry Pi 3 should look like at this point.

Step 1

Place the camera mount over the top place as in Figure 4.66

Step 2

Insert the M3x10 screws from the opposite side of the camera mount (see Figure 4.68)

Step 3

Fasten using M3 nuts (Figure 4.70)). Make sure that the camera is facing forward direction as perfectly as possible.

Step 1

Place the M2.5 spacers on the bottom side of the Raspberry Pi, as in Figure 4.74.

Step 2

Place the Raspberry Pi under the top plate, positioned according to Figure 4.76. Fasten it using the M2.5x10 nylon screws.

Step 1

Pass the camera cable through the top plate as in the picture, pay attention to the connector orientation, it must be the same as in Figure 4.80.

Step 2

Pass the camera cable through the camera mount (Figure 4.82).

Step 3

Pull the black wings of the camera port on the camera and plug in the camera cable. Pay attention that the pins on the camera cable match the pins on the camera. Close the connector by pushing the black wings making sure it “clicks”. (Figure 4.84).

Step 4

Place the camera on the camera mount, and insert the M2x10 screws from the front to the back, as in Figure 4.86.

Step 5

Secure the camera from the back using the M2 nuts. (Figure 4.88).

Step 1

Place the top chassis assembly over the bottom chassis assembly as in Figure 4.92.

Step 2

For each motor, the cable that is soldered closer to the floor (bottom), goes on the internal connection. The cable soldered on the motor on the plate side goes on the external connection.

Insert the right-motor cable on the right side of the Hut connector (Figure 4.94 perspective), and the left-motor cable on the left side of the Hut connector.

For reference, look at the example in Figure 4.96, where the left motor (driving perspective) has the red wire soldered on the bottom, so it goes on the internal left connector. Similarly, the right motor (driving perspective) has the black wire soldered on the bottom, so it goes on the internal right connector.

You might find it easier to temporarily remove the USB cables while executing this passage. Make sure that you plug them back in before moving to the next one though.

Step 3

Now flip the chassis top plate assembly, it should look like in Figure 4.98.

Step 4

Place the second rear bumper bracer on top of the chassis spacers in the back of the chassis, again the holes should align (Figure 4.100). If you experience a slight misalignment, carefully pass an M3 screw through the top plate and the top bumper bracer first, then move the standoff until you can plug the screw in.

Step 5

Fasten the top plate using the M3x10 screws, as in(Figure 4.102.

Step 6

Modified 2018-09-14 by tanij

You can use a zip tie to help with cable management (Figure 4.104). Tip: you can use one zipties to keep the camera cable down and the USB cables below from touching the wheels.

Step 1

Mount the spacers using the metal screws, as in Figure 4.108.

Step 2

Take the back plate and place the countersunk screws on the side where the holes are tapered, as shown in Figure 4.110.

Step 3

Fasten the back plate to the back bumper standoffs, like shown in the picture. The back plate is not symmetric, place it such that it is centered with respect to the back bumper. Then apply the circle pattern sticker to the back plate (Figure 4.112).

Step 1

Place the front bumper in front of the chassis. Then locate the pins on the front bumper, you should have taken note of the connection you have done on the Duckietown Hut (Figure 4.116).

Step 2

You can pass the jumper cables through the top chassis for cable management purposes. No matter what exact solution you choose to, the objective is to avoid any cable from touching the wheels (Figure 4.118).

Step 3

Now we need to connect the two set of wires to the front bumper. The set of cables coming from the Raspberry Pi must be connected on the right (Figure 4.120 perspective, namely the green blue and yellow wires in the picture), while the connector on the left (red white and black wires in the picture) will go to the back bumper. Again take note of which color you used for which pin in the left connector.

Step 5

Place the cabled front bumper in front of the chassis, with your fingers slightly lift the top plate and insert the front bumper. It is a form fit, the connector on the lower part must go in the circular hole (see Figure 4.122), while the two top connectors will lock in just behind the camera mount (refer to Figure 4.124). You might need to apply some pressure once found the correct alignment for the components to “lock in”.

Part 6

Insert and fasten the screws trough the top plate in the front chassis spacers.

Step 1

Place the back bumper as shown in Figure 4.128, then connect the wires to the back bumper according to the connection done in the front bumper.

Step 2

The back bumper is press fit to the bumper bracers, place it as in Figure 4.130. You will have to apply little pressure, and it should fit tightly.

If you cannot get the bumper to fit, check if the bumper bracer has plastic protective films on both sides. In case, remove one - try again - and in case remove the other one too.

If you experience a loose fit instead, you can use two M3 screws and nuts to secure the back bumper.

Check the outcome

Figure 4.134 shows how the current assembly should look like at this point.

Step 1: Visual inspection

Modified 2018-11-07 by tanij

If the GPIOs of the Hut get shorted (there is an electrically conductive connection between them) when you plug in the battery, you might damage the Raspberry Pi beyond repair.

Step 2: Plug in the battery

Modified 2018-11-07 by tanij

Place the battery and fix it using a zip tie, then connect the USB cables, as in Figure 4.138.

Step 2

Place the Duckie on top of your brand new Duckiebot.

Check the outcome

Figure 4.140 and Figure 4.142 show how the final assembly should look like. Congratulations!