Extra Parts

These parts you may either already have, depend on where you're located for a good deal, depend on personal preference, or are optional. If you do not have any of these, you'll need to add around $500 to the total project cost.

Note: Make sure to go through the list below to make sure you have everything you need.

The PCBs

The electronics of the rover consist of two boards: the brain board and the motor board. To order these boards we suggest that you order from JLCPCB, this PCB fabrication company is quite inexpensive for this board size and has good turnaround time. You'll either have to order the required minimum of 10 pieces or you can ask on the Slack group whether someone wants to put in a group order or already has some extras. Upload the .zip files individually and make sure the following settings are set:

jlcpcb settings

The body plates

The body plates that attach to all sides of the body are designed to be made from laser cut acrylic, MDF, hardwood, or similar. The 2D cutout files are the .dxf files in the laser cut parts folder. They were designed to be around 3mm thick (1/8"). You can choose a material and cut them at your local makerspace's laser cutter or order them from an online service like Sculpteo or SendCutSend. Check the README in that folder for more details.

A gamepad or remote controller

This is technically not a requirement, especially if you're planning on making the rover autonomous, but is highly recommended. Any USB based option should work here.

Some options are getting an XBox controller with a usb dongle or for longer range; the pricier Spektrum WS2000 with Spektrum DXs transmitter. Many alternatives exist and will work ok.

Standoff kit for the boards

You'll want these to mount the PCBs to the rover body. Many options exist here, for example this kit.

Wiring

We recommend getting spools of 18AWG (red and black), 20AWG (white, red, black) and 22AWG wire (4 colors). The wire has to be stranded and not solid core as it will bend during operation. For each wire type, if possible, get ribbon cable where each wire is attached to another one which will help with keeping wiring clean and manageable.

To protect the cables from chafing against the sharp aluminum parts, we recommend cable sleeves. You can also use grommets, filing down the sharp edges or burs, applying tape to the edges, or using expandable wire sleeving.

Heat shrink is a must have for keeping cables nice and snug.

Take a look at the wiring overview to get an idea of what you will be building. You'll need crimps and connectors for DuPont, Bullet, XT30, JST, and Molex styles. Crimping doesn't have a 100% success rate, so we recommend getting extras or buying a kit if you're planning on using them for other projects as well. Here are some options for each set you need:

  • A Raspberry Pi ribbon cable, e.g. from Adafruit but available in many places. While you could use header pins for this connection, the cable is the cleanest solution
  • A USB-C power breakout cable if you're using a Raspberry Pi 5, e.g. from Amazon
  • XT30 connectors for the power connections on the motor PCB.
  • DIY options, either:
  • premade from GoBilda: 2x male leads, 2x female leads
  • 6 4-pin JST connections:
  • 6x premade JST to jumper wires from GoBilda
  • JST connector kit
  • 6 6-pin Molex PCI-E connections. Digikey carries a couple options. In either case, be sure to get enough for 6 connectors.
  • housings and pins
  • assemblies are sometimes available but the 16 AWG wire may be difficult to work with
  • 4 3-pin DuPont and 8 4-pin DuPont connectors
  • DuPont connector kit
  • Buy precrimped wires+connectors from various sources
  • 12 female 3.5mm Bullet connectors. Make sure you're getting the right size connectors and ones that come insulated.
  • GoBilda has various combinations available that you can cut/solder/crimp. They use 16AWG wire which is on the thicker side. Make sure you're getting the Female connector type.
  • Buy a DIY kit
    • The GoBilda connector pack is good quality but only has 5 female connectors so you would need 3 of them.
    • from Amazon (insulators are flimsy but ok)

Threadlocker

You will want threadlocker for several screws so that they don't unscrew themselves while driving. You can find this everywhere, for example at Gobilda. Make sure you get blue as opposed to red so it's not permanent.

Tools

  • A combination nut driver will save you time screwing and unscrewing (lock)nuts inside the body.
  • You'll need 2.5mm and 3mm hex keys for the button and socket M4 screws respectively. For example Gobilda 2.5 and Gobilda 3.
  • A crimping tool for Molex, JST, DuPont connectors. A regular crimping tool should be able to handle all of these without issue. While you can technically complete a crimp without a crimping tool, it often won't be as consistent or strong as with a proper crimper. Various connector sets come with a decent crimper.

Electrical

  • Voltage Regulators:
  • 1 X 5V Regulator: Pololu
  • 1 X 12V Regulator: Pololu
  • 3 X Roboclaw 2x7A Motor Controller Basic Micro
  • 1 X Power Measurement Unit INA260: Sold out on DigiKey, possible replacements are on Adafruit
  • 1 X PCA9685 steering servo driver Mouser
  • DC power meter: Amazon. This LCD display reads out current, voltage, power, and energy, and can be put on the back where the rectangular hole is in the laser cut cover.
  • batteries: many options available here. We recommend getting LiPo batteries. You'll need a battery that can provide over 14V(*), so a 4s battery works well. You can get batteries with various mAh ratings (how many milliAmperes the battery can output for 1 hour). We recommend any option over 4000mAh. Higher capacity comes at a higher cost. You can also get more than one battery and swap them out. The rover can carry them as well.
  • Zeee sells many options on Amazon
  • You'll also need a charger for the battery. Make sure it can support the battery you bought, chemistry-wise and connector-wise. For the Zeee options, this B6 Lipo Balance Charger from Amazon will work.
  • Consider getting a fireproof battery bag. LiPo batteries are extremely flammable/explosive and a fire caused by a battery is extremely difficult to put out.
  • You'll also need a way to connect your battery to the PCB via a XT30 connector (MH-FC) which depends on the battery you get. Often these come with the charger for the battery
  • A Raspberry Pi 3, 4, or 5 and SD card for the operating system. For the 4 or 5, any amount of RAM should work just fine. Note that only the 5 has two full serial interfaces and thus is the only model that can connect to the motor controllers (Roboclaws) and run bluetooth at the same time.

(*) The reason you need 14V is that the 12V regulator needs a dropout voltage on top of the output voltage in order to provide 12V. A 12V battery will not work adequately.

Different wheels

  • The wheels we previously included as the default from DollarHobbyz are $34.95 per pair of two for a total of $104.85 (excl. shipping), saving ~$135 compared to the default Wasteland wheels. They are a perfectly fine choice but require some drilling to fit to the motor hubs.
  • Gobilda also sells a larger version of the Wasteland Wheel at 192mm diameter. This adds $90 total compared to the default Wasteland wheels. No drilling is required. Those wheels are bigger and wider and look like this:
smaller Wasteland wheels bigger Wasteland wheels

There is a software parameter where you can easily modify the size of the wheels to account for speed differences.

Maintaining the Parts List

Parts can become out of stock or discontinued in the future. In this case, the part list can be modified by editing parts_list.csv, which covers all the mechanical parts, digikey_bom.csv, which covers most of the electrical part, and extra_parts.md to cover the rest. After doing so, you can compile to update the README.md file using csv_to_md.py (The compilation will also happen automatically with a merge). Do not edit README.md directly, as it will be overwritten by the compilation process.