Build JPL Open Source Rover

Steps

26

Subassemblies

11

Hands-on time (sum)

5 h

Critical path

5 h

Your progress · this device

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25 steps have no time estimate; times above are lower bounds.

1. Procurement
   01

   Order goBILDA, DigiKey and extra parts

   Order from the parts list early: goBILDA mechanical parts (parts_list.csv), the DigiKey cart (upload digikey_bom.csv directly at DigiKey), and the extra parts (RoboClaws, regulators, PCA9685, INA260, battery, charger, connectors, wire). Educational builders can apply for the 15% goBILDA discount through the form linked in the main README before ordering.

   CHECKEvery row of parts_list.csv and digikey_bom.csv is in a cart at the listed quantity, and extra_parts.md items are ticked off.

   Parts in

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   Start

   Source

   github.com

2. 02

   Order the two control-board PCBs

   Upload motor_board_v2.0.3.zip and brain_board_v2.0.3.zip from electrical/pcb/control_board/gerbers/gerber_files/ to JLCPCB one at a time, with the settings shown in jlcpcb_ordering.png. Minimum order is 10 of each; ask on the OSR Slack about group orders or spares.

   CHECKTwo bare boards match the v2.0.3 silkscreen (motor board with RC1-RC3 footprints, brain board with J22/J23 ribbon headers).

   Parts in

   • OSR Motor Board PCB v2.0.3 (gerber zip)electronics.pcb-motor-board
   • OSR Brain Board PCB v2.0.3 (gerber zip)electronics.pcb-brain-board

   Tools

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   Start

   Source

   github.com

3. Fabrication
   03

   Laser cut the body plates

   Cut the DXF files from mechanical/body/laser_cut_parts/dxf/ in ~3 mm material. The side plate and gap slat are single files: cut two of each. Optionally engrave the top front plate from the Opaque or Clear PDF.

   CHECKNine plates: bottom, 2 sides, 2 gap slats, top front, top rear, front and back; holes accept M4 screws.

   Parts in

   • Bottom plate (bottom_plate.dxf; PCB standoff holes)laser.bottom-plate
   • Side plate (side_plate.dxf; one file, cut two)laser.side-plate
   • Gap slat (gap_slat.dxf; one file, cut two)laser.gap-slat
   • Top front plate (top_front.dxf; optional mission-patch engraving PDFs)laser.top-front
   • Top rear plate (top_rear.dxf)laser.top-rear
   • Front plate (front_plate_standoff.dxf)laser.front-plate
   • Back plate (back_plate_standoff.dxf; switch hole and power-meter cut-out)laser.back-plate

   Tools

   Laser cutter or an online service (SendCutSend premade cart, Sculpteo)

   Torque

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   Start

   Source

   github.com

4. Wiring
   04

   Build the 12 motor cables

   Cut wire (length + 1 cm): servo 20 AWG 2x54 cm and 2x36 cm; encoder 22 AWG 4x36, 2x53, 2x46, 2x54 cm; power 18 AWG red/black pairs 2x3, 2x54, 2x41 cm. Build (1) 4x JST 4-pin to DuPont female 4-pin, 35 cm; (2) 4x DuPont male 4-pin to Molex PCI-E, 2x52 cm front ('F') and 2x45 cm back ('B'); (3) 2x JST 4-pin to Molex PCI-E, 53 cm, middle ('M'); (4) 6x female bullet pair to the free Molex slots (2 cm middle, 53 cm front, 40 cm back); (5) 4x DuPont male 3-pin to female 3-pin servo extensions (2x53 cm, 2x35 cm). Mark pinouts on each housing (JST: enB, enA, GND, 5V; PCI-E top 5V/enA/enB, bottom M+/M-/GND).

   CHECK12 finished cables; every conductor beeps end to end on continuity and no pin is swapped against the pinout photos; each crimp survives a firm tug.

   Parts in

   • Stranded wire: 18 AWG red/black (motor power), 20 AWG white/red/black (servo), 22 AWG in 4 colours (encoder), 16 AWG for RoboClaw headers; ribbon style preferredcable.wire-spools
   • 4-pin JST-XH encoder breakout cable to 4 x DuPont (premade, 300 mm)cable.jst-encoder-breakout
   • 6-pin Molex PCI-E housings + female pins (6 drive-motor connectors)cable.molex-pcie-6pin
   • DuPont connector kit (4x 3-pin and 8x 4-pin housings, male and female crimps)cable.dupont-kit
   • Insulated female 3.5 mm bullet connectors (drive motor power)cable.bullet-3-5mm
   • Cable sleeving / expandable braid and heat shrinkcable.sleeve-heatshrink

   Tools

   Crimping tool (JST, DuPont, Molex), Wire strippers, Heat gun, Multimeter, Marker

   Torque

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   Time

   5 h

   After

   Start

   Source

   github.com

5. Power
   05

   Prepare the LiPo battery, charger, switch and meter leads

   Safety · human-verified required

   Balance-charge the 4S LiPo with a charger that matches its chemistry and connector, inside a fire-proof bag, never unattended. Give the battery an XT30 (MH-FC) lead, and wire the ON-OFF-ON toggle (B9) and the DC power meter with XT30 plugs for the Switch, MM Load and MM DC headers. Insulate every joint; LiPo packs deliver very high short-circuit current. Do not discharge the pack too far (the rover powers down below about 13-14 V).

   CHECKBattery reads over 14 V and cells are balanced; switch lead shows open/closed on continuity; no exposed conductor at any joint.

   This step can hurt a person or ruin parts. Its instructions need sign-off by a human who has done it before relying on them. Stop and ask if anything differs from what you see.

   Parts in

   • 4S LiPo battery, over 14 V, 4000 mAh or more recommended, with XT30 (MH-FC) leadpower.battery-4s-lipo
   • LiPo balance charger matching the battery chemistry and connector (e.g. B6)power.lipo-charger
   • Fireproof LiPo battery bag (recommended)other.lipo-fire-bag
   • B9: SWITCH TOGGLE ON-OFF-ON (main power switch)electronics.dk-b9
   • DC power meter with LCD (voltage, current, power, energy; mounts in the rear plate cut-out; MM Load/MM DC XT30 headers)sensor.dc-power-meter
   • XT30 connectors (board power headers J1/J3/J4/J5, battery, switch and meter leads)cable.xt30

   Tools

   Soldering iron, Multimeter, Heat shrink

   Torque

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   Time

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   Start

   Source

   github.com

6. Wheels
   06

   Build six base wheel assemblies

   On each of the six 5203 motors fit a clamping mount and a Hyper Hub, then bolt a Wasteland wheel to the hub (3 socket M4x16 per wheel) and the motor to its 2-hole U-channel (4 M4x10). Leave positions adjustable. Build left and right as mirror images: all U-channel openings point to the rear of the rover (the Onshape model shows them identical by mistake).

   CHECKSix wheel assemblies spin freely by hand, three per side as mirror images.

   Parts in

   • Wasteland Wheel (144mm Diameter, 52mm Width)structure.wasteland-wheel-144
   • 1401 Series 2-Side, 2-Post Clamping Mount (43mm Width, 36mm Bore)structure.clamping-mount-43-36
   • 5203 Series Yellow Jacket Planetary Gear Motor (26.9:1, 24mm length 8mm REX shaft, 223 RPM, 3.3-5V encoder)actuator.yellow-jacket-5203-223rpm
   • 1310 Series Hyper Hub (8mm REX Bore)structure.hyper-hub-8mm-rex
   • 1120 Series U-Channel (2 Hole, 72mm Length) (6 for the wheels + 2 for the body)structure.u-channel-2h-72
   • M4 x 16mm socket head screw - 25 Packfastener.m4x16-socket-25
   • M4 x 10mm socket head screw - 25 Packfastener.m4x10-socket-25
   • M4 x 10mm button head screw - 25 Packfastener.m4x10-button-25

   Tools

   3 mm and 2.5 mm hex keys

   Torque

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   Time

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   After

   Start

   Source

   github.com

7. Rocker-bogie
   07

   Rocker-bogie joints and control arms (x2)

   Assemble each joint on its 8 mm shaft: the 4 mm spacer (1522-0010-0040) on the clamp's protruding side, the 6 mm spacer on the flat side. Press the flanged bearing into the hub, then fix the hub to a control arm with 8 M4 x 12 (or 10) mm screws with washers so the bearing cannot fall out.

   CHECKJoint has no side-to-side play and turns smoothly; bearings are captured.

   Parts in

   • 1309 Series Sonic Hub (8mm Bore)structure.sonic-hub-8mm
   • 1611 Series Flanged Ball Bearing (8mm ID x 14mm OD, 5mm) - 2 Packstructure.flanged-bearing-8x14x5
   • 1504 Series 32mm OD Pattern Spacer (2mm Length)structure.pattern-spacer-32-2mm
   • 2100 Series Stainless Steel Round Shaft (8mm Diameter, 50mm Length)structure.shaft-8x50
   • 1221 Series 2-Side, 2-Post Pattern Mount (32-2)structure.pattern-mount-32-2
   • 1522 Series 8mm ID Spacer (10mm OD, 6mm Length) - 4 Packstructure.spacer-8id-6mm
   • 1522 Series 8mm ID Spacer (10mm OD, 4mm Length) - 4 Packstructure.spacer-8id-4mm
   • Plastic Hub-Mount Control Arm (72mm Length)structure.control-arm-72
   • M4 x 12mm socket head screw - 25 Packfastener.m4x12-socket-25
   • M4 washer (4mm ID x 8mm OD), zinc plated - 25 Packfastener.m4-washer-25

   Tools

   Hex keys

   Torque

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   Time

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   After

   Start

   Source

   github.com

8. Body
   08

   Body frame, bearing supports and plate hinges

   Bottom frame: 2x 29-hole and 2x 41-hole beams with M4x16 screws, cross beams 1 hole in, plus a 29-hole beam at hole 16 from the front. Top frame the same. Verticals: 8x 12-hole beams at holes 1, 17, 25, 41 on both sides. Build two bearing supports (pillow blocks, hollow sides toward the centre) and fix them at hole 17 (M4x12 outboard, M4x8 inboard), on the 6th hole from the top and 5th from the bottom of the verticals. Hinges: 22 mm standoffs on 3x5 plates with M4x8, plates on the top front and rear beams, hinges on the standoffs.

   CHECKFrame is square and rigid; both pillow-block bores line up across the body.

   Parts in

   • 1106 Series Square Beam (29 Hole, 232mm Length)structure.square-beam-29h
   • 1106 Series Square Beam (41 Hole, 328mm Length)structure.square-beam-41h
   • 1106 Series Square Beam (12 Hole, 96mm Length)structure.square-beam-12h
   • 1604 Series 2-Side, 2-Post Pillow Block (32mm Bore)structure.pillow-block-32
   • 1116 Series Grid Plate (3 x 5 Hole, 24 x 40mm) (4 for the rocker-bogies + 4 for the body hinges)structure.grid-plate-3x5
   • 1501 Series M4 x 0.7mm Standoff (6mm OD, 22mm Length) - 4 Packfastener.standoff-m4-22
   • Plastic Hinge - 2 Packstructure.plastic-hinge
   • M4 x 16mm socket head screw - 25 Packfastener.m4x16-socket-25
   • M4 x 12mm socket head screw - 25 Packfastener.m4x12-socket-25
   • M4 x 8mm socket head screw - 25 Packfastener.m4x8-socket-25

   Tools

   Hex keys, 7 mm combination nut driver

   Torque

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   Time

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   After

   Start

   Source

   github.com

9. Software
   09

   Install Ubuntu, ROS 2 and the rover code on the Pi

   Flash Ubuntu LTS with SSH, user, Wi-Fi and locale set; install ROS 2 (guide assumes Jazzy, `sudo apt install ros-jazzy-ros-base`). Then `mkdir -p ~/osr_ws/src && cd ~/osr_ws`, `source /opt/ros/${ROS_DISTRO}/setup.bash`, `cd src && git clone https://github.com/nasa-jpl/osr-rover-code.git && cd ..`, `python3 -m venv venv --system-site-packages`, `source ./venv/bin/activate`, `touch ./venv/COLCON_IGNORE`, `sudo rosdep init`, `rosdep update`, `rosdep install --from-paths src --ignore-src --rosdistro=$ROS_DISTRO -y`, `python3 -m pip install adafruit-circuitpython-servokit ina260 RPi.GPIO smbus`, `python3 -m colcon build --symlink-install`. Create `osr_params_mod.yaml` and `roboclaw_params_mod.yaml` in osr_bringup/config. Enable I2C and Serial (no login shell) in `sudo raspi-config`, copy udev rules `sudo cp ~/osr_ws/src/osr-rover-code/config/* /etc/udev/rules.d/`, add the user to tty, dialout and input, and reboot.

   CHECK`ros2 topic list` runs, `echo $ROS_DISTRO` prints the distro, and `ls -l /dev/serial*` shows `/dev/serial0 -> ttyS0`.

   Parts in

   • Raspberry Pi 3, 4 or 5 (any RAM) + microSD card; only the Pi 5 can run the RoboClaw serial link and Bluetooth at the same timecompute.raspberry-pi

   Tools

   Raspberry Pi Imager, SSH client

   Torque

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   Time

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   After

   Start

   Source

   github.com

10. Control board
    10

    Motor board: power headers, fuse holder, R1 and D1

    Fit M2.5 x 30 mm standoffs to the bare board as a work stand. Solder XT30 headers J1 (male), J3 (female), J4 (female), J5 (male) with plenty of solder, plus fuse holder F1, resistor R1 and diode D1 (check D1 orientation).

    CHECKXT30 genders match the list and D1's band matches the silkscreen.

    Parts in

    • OSR Motor Board PCB v2.0.3 (gerber zip)electronics.pcb-motor-board
    • XT30 connectors (board power headers J1/J3/J4/J5, battery, switch and meter leads)cable.xt30
    • A7: FUSEHOLDER BLOCKS - PCB - CLIP Celectronics.dk-a7
    • A5: DIODE SCHOTTKY 25V 10A TO220ACelectronics.dk-a5
    • Metric M2.5 standoff kit (30, 20, 15, 12, 10, 6 mm lengths used on the PCBs)fastener.m2-5-standoff-kit

    Tools

    Soldering iron, Solder

    Torque

    —

    Time

    —

    After

    02

    Source

    github.com

11. Wheels
    11

    Build four corner assemblies and route their cables

    Take four of the six wheel assemblies. Fit grommets at both ends of each 144 mm goRAIL. Route a DuPont-to-JST encoder cable through the low-side U-channel, goRAIL and motor bracket (DuPont at top, JST at the motor), and the motor power leads the other way. Join with 3-4 M4x6 button screws inside the U-channel and 3-4 M4x8 socket screws at the top, loosely at first; sleeve the wires against sharp aluminium edges. Optionally notch the goRAIL above the U-channel for clearance. Build two mirrored pairs.

    CHECKFour corners in two mirrored pairs; no wire pinched in the channel; JST plugs reach the motor encoders.

    Parts in

    • 1109 Series goRAIL (144mm Length)structure.gorail-144
    • 1121 Series Low-Side U-Channel (4 Hole, 120mm Length)structure.low-side-u-channel-4h-120
    • Plastic Grommet (14-1) - 12 Packother.grommet-14-1
    • M4 x 6mm button head screw - 25 Packfastener.m4x6-button-25
    • M4 x 8mm socket head screw - 25 Packfastener.m4x8-socket-25
    • Cable sleeving / expandable braid and heat shrinkcable.sleeve-heatshrink

    Tools

    Hex keys, File (optional notch)

    Torque

    —

    Time

    —

    After

    06, 04

    Source

    github.com

12. Rocker-bogie
    12

    Bogie, front servo and wiring (x2, mirrored)

    Fix a 3x5 grid plate to two 96 mm goRAILs with M4x10 button screws (slits toward the plate's short side), then to a 3-hole flat beam and the bogie joint with M4x10 socket screws, slits facing the top. Add the 3-1 angle bracket on top and a 2-hole U-channel below. Fit grommets, route the front servo cable (with a 54 cm extension), front encoder, middle motor power and middle encoder cables. Put the servo into its ServoBlock, insert the set screw into the hollow shaft but leave it loose for calibration, and mount on the front bracket.

    CHECKBoth bogies are mirror images with slits facing the same way; servo set screw is loose; cables sit inside the channels.

    Parts in

    • 1116 Series Grid Plate (3 x 5 Hole, 24 x 40mm) (4 for the rocker-bogies + 4 for the body hinges)structure.grid-plate-3x5
    • 1118 Series Open goRAIL (96mm Length)structure.open-gorail-96
    • 1102 Series Flat Beam (3 Hole, 24mm Length) - 2 Packstructure.flat-beam-3h-24
    • 1111 Series Angle Pattern Bracket (3-1)structure.angle-bracket-3-1
    • 1120 Series U-Channel (2 Hole, 72mm Length) (6 for the wheels + 2 for the body)structure.u-channel-2h-72
    • ServoBlock (Standard Size, 25 Tooth Spline, Hub Shaft)structure.servoblock-25t
    • 2000 Series Dual Mode Servo (25-2, Torque) (corner steering)actuator.servo-2000-25-2
    • Plastic Grommet (14-1) - 12 Packother.grommet-14-1
    • M4 x 10mm button head screw - 25 Packfastener.m4x10-button-25
    • M4 x 10mm socket head screw - 25 Packfastener.m4x10-socket-25

    Tools

    Hex keys

    Torque

    —

    Time

    —

    After

    07, 04

    Source

    github.com

13. Body
    13

    Differential pivot

    Assemble the idler bearing hub per goBILDA's instructions. Fix the block mount to the 7-hole linkages with M4x10 button screws. Make two turnbuckles from threaded rod and a ball linkage on each end. Connect each turnbuckle to a 7-hole linkage (M4x20 socket + locknut) and to the second hole from the end of the U-beam (M4x16 button + locknut). Fix the pivot to the hub with two M4x6 button screws, add two 29-hole beams at holes 28 and 30 and mount the hub to them with M4x12 socket screws.

    CHECKThe differential bar rotates freely about the hub with no binding at the turnbuckles.

    Parts in

    • Idler Bearing-Hub (32mm OD, 16mm Height)structure.idler-bearing-hub-32
    • 1205 Series Dual Block Mount (1-4) - 2 Packstructure.dual-block-mount-1-4
    • 1203 Series Block Mount (1-1) - 4 Packstructure.block-mount-1-1
    • 1102 Series Flat Beam (7 Hole, 56mm Length) - 2 Packstructure.flat-beam-7h-56
    • 2808 Series Stainless Steel Threaded Rod (M4 x 0.7mm, 50mm Length) - 2 Packstructure.threaded-rod-m4-50
    • 2913 Series Steel Ball Linkage (Female M4 x 0.7mm, 24.1mm Length) - 2 Packstructure.ball-linkage-m4
    • 1101 Series U-Beam (41 Hole, 328mm Length)structure.u-beam-41h
    • M4 x 0.7 nylon-insert locknut (7mm hex) - 25 Packfastener.m4-locknut-25
    • M4 x 20mm socket head screw - 25 Packfastener.m4x20-socket-25
    • M4 x 16mm button head screw - 25 Packfastener.m4x16-button-25
    • M4 x 10mm button head screw - 25 Packfastener.m4x10-button-25

    Tools

    Hex keys, Wrench

    Torque

    —

    Time

    —

    After

    08

    Source

    github.com

14. Control board
    14

    First power: test the power path at 14.8 V / 1.0 A

    Safety · human-verified required

    Insert the 10 A fuse (B1) in F1. Connect the Switch and meter leads, then a bench supply at 14.8 V DC current-limited to 1.0 A (or the battery). Measure between T4 (swt_out) and T2 (Batt-). Disconnect power before fitting any further parts.

    CHECKT4-T2 reads the supply voltage (~14.8 V) and the power meter shows the same; supply stays below the current limit. A brief continuity beep on J5 is normal once capacitors are fitted.

    This step can hurt a person or ruin parts. Its instructions need sign-off by a human who has done it before relying on them. Stop and ask if anything differs from what you see.

    Parts in

    • B1: FUSE GLASS 10A 125VAC 5X20MM (main fuse, 1 used + 1 spare)electronics.dk-b1

    Tools

    Bench power supply (current limited), Multimeter

    Torque

    —

    Time

    —

    After

    10, 05

    Source

    github.com

15. Rocker-bogie
    15

    Rocker, back servo and 45-degree brackets (x2, mirrored)

    Fix each control arm to the steel bracket and a 5-hole goRAIL nut with 7 socket screws and washers (no goRAIL nut: use 3 hurricane nuts, see the collapsed section). Route front/middle/rear cables through the slit and tighten fully. Fix the 1-hole U-channel to the 288 mm goRAIL with 3-4 M4x10 socket screws and mount the second ServoBlock + servo with 6 M4x10 button screws. Join front and back with the 45-degree brackets using hurricane nuts and M4x6 socket screws (longer screws hit the goRAIL). Fit the body-axis channel with 5 hurricane nuts, flush, cables inside.

    CHECKTwo mirrored rocker-bogies; the joint pivots freely; all cables exit through the body-axis channel; hurricane nuts are locked in the rail.

    Parts in

    • 1126 Series Steel Flat Bracket (1-1) - 2 Packstructure.steel-flat-bracket-1-1
    • goRAIL Nut (5 Hole) - 2 Packfastener.gorail-nut-5h
    • 1118 Series Open goRAIL (288mm Length)structure.open-gorail-288
    • 1120 Series U-Channel (1 Hole, 48mm Length)structure.u-channel-1h-48
    • ServoBlock (Standard Size, 25 Tooth Spline, Hub Shaft)structure.servoblock-25t
    • 2000 Series Dual Mode Servo (25-2, Torque) (corner steering)actuator.servo-2000-25-2
    • 1111 Series Angle Pattern Bracket (1-1) (45 degree bracket)structure.angle-bracket-1-1
    • 1137 Series Steel Flat Grid Bracket (1-1) - 2 Packstructure.steel-flat-grid-bracket-1-1
    • 1118 Series Open goRAIL (120mm Length)structure.open-gorail-120
    • Hurricane Nut for goRAIL - 25 Packfastener.hurricane-nut-25
    • M4 x 6mm button head screw - 25 Packfastener.m4x6-button-25
    • M4 x 8mm socket head screw - 25 Packfastener.m4x8-socket-25

    Tools

    Hex keys, Needle-nose pliers

    Torque

    —

    Time

    —

    After

    12

    Source

    github.com

16. Control board
    16

    Motor board: INA260 (or bypass), 5 V, 12 V and 3.3 V regulators

    Option 1: fit 8x1 and 3x1 (centre pin removed) female sockets on U1 underneath, male pins on the INA260, bridge pads A0 and A1 (I2C address 0x45) and plug it in. Option 2: no INA260, fit a 0 ohm link in R30. Then: 5 V regulator into U4 on two 4x1 + one 5x1 female headers; 12 V regulator into U3 on a 5x1 header with M2.5 x 10 mm standoffs; U7 3.3 V linear regulator and C7 (both polarity/orientation sensitive); R15, R24 and Q1 for the alert LED.

    CHECKINA260 A0/A1 bridged (or R30 fitted); U7 and C7 match the orientation photos.

    Parts in

    • INA260 current/voltage/power breakout (optional; bypass with a 0 ohm link in R30 if absent)sensor.ina260
    • Pololu 5 V step-down regulator (product 2881; U4, powers the 5 V motor bus)power.reg-5v
    • Pololu 12 V step-down regulator (product 2855; U3)power.reg-12v
    • A38: IC REG LINEAR 3.3V 750MA TO220-3electronics.dk-a38
    • A4: CAP ALUM 10UF 20% 50V RADIALelectronics.dk-a4
    • A21: TRANS PNP 40V 0.2A TO92-3electronics.dk-a21
    • A25: RES 0 OHM JUMPER 1/4W AXIALelectronics.dk-a25
    • Assorted female/male pin header kit (regulators, RoboClaws, INA260, PCA9685)electronics.header-kit
    • B11: TERM BLOCK HDR 24POS VERT 5MM (break up for PCA9685 / INA260 power pins)electronics.dk-b11

    Tools

    Soldering iron

    Torque

    —

    Time

    —

    After

    14

    Source

    github.com

17. 17

    Test every voltage rail

    Safety · human-verified required

    Power the board at 14.8 V, current limited, and probe test points T7 to T12 on the left of the top side against the silkscreen values (3.3 V, 5 V, 12 V, Batt+, PWR). Disconnect power afterwards.

    CHECKEach test point reads its silkscreen voltage; nothing warms up.

    This step can hurt a person or ruin parts. Its instructions need sign-off by a human who has done it before relying on them. Stop and ask if anything differs from what you see.

    Parts in

    —

    Tools

    Bench power supply, Multimeter

    Torque

    —

    Time

    —

    After

    16

    Source

    github.com

18. 18

    Motor board: PCA9685, RoboClaws and remaining parts

    Unpowered: U2 headers (6x1 + three 2x4 female) and the PCA9685 with its V+/GND fed by two short wires or 1x1 pins, then C3; R5 and C1 (INA260 helpers); J21, J20 (8x1 female) and R6-R10; R2-R4. For RC1-RC3: M2.5 x 15 mm standoffs, a 2x10 and a 5x1 female header each, and the four capacitors per footprint. Fit J16-J18 motor supply headers, wire each 6-pos terminal block to its RoboClaw 1:1 with ~5 cm of 16 AWG (18 AWG also fine), and seat the three RoboClaws. Finish with C5, C6, J19 servo header, C19 (polarity), LED array U5 (bevelled corner) and drive motor headers J8-J11, J13, J14.

    CHECKThree RoboClaws seated; C19 and U5 orientation matches the photos; INA260 test from an Arduino at address 0x45 prints bus voltage near the supply voltage (optional).

    Parts in

    • PCA9685 16-channel PWM board (corner servo driver, U2)electronics.pca9685
    • RoboClaw 2x7A motor controller (one per two drive motors)electronics.roboclaw-2x7a
    • A9: TERM BLOCK HDR 6POS VERT 3.5MM (RoboClaw headers J16-J18)electronics.dk-a9
    • B2: TERM BLOCK PLUG 6POS STR 3.5MM (RoboClaw terminal plugs)electronics.dk-b2
    • A1: CAP CER 10000PF 50V X7R RADIALelectronics.dk-a1
    • A2: CAP ALUM 100UF 20% 50V RADIALelectronics.dk-a2
    • A3: CAP CER 0.1UF 50V X7R RADIALelectronics.dk-a3
    • A6: DIODE GEN PURP 75V 300MA DO35electronics.dk-a6
    • A10: CONN HEADER VERT 12POS 2.54MMelectronics.dk-a10
    • A11: CONN HEADER VERT 8POS 2.54MMelectronics.dk-a11
    • A12: CONN HDR 20POS 0.1 TIN PCBelectronics.dk-a12
    • A13: CONN HEADER VERT 40POS 2.54MMelectronics.dk-a13
    • A14: CONN HEADER VERT 6POS 2MMelectronics.dk-a14
    • A16: CONN HEADER VERT 20POS 2.54MMelectronics.dk-a16
    • A17: CONN HDR 2POS 0.1 TIN PCBelectronics.dk-a17
    • A19: TERM BLK 2P SIDE ENT 5.08MM PCBelectronics.dk-a19
    • A20: CONN HEADER VERT 6POS 4.2MM (drive motor headers)electronics.dk-a20
    • A22: RES 100 OHM 5% 1/4W AXIALelectronics.dk-a22
    • A23: RES 10K OHM 5% 1/4W AXIALelectronics.dk-a23
    • A24: RES 4.7K OHM 5% 1/4W AXIALelectronics.dk-a24
    • A26: RES 68 OHM 5% 1/8W AXIALelectronics.dk-a26
    • A27: RES 82 OHM 5% 1/4W AXIALelectronics.dk-a27
    • A28: RES 1K OHM 5% 1/4W AXIALelectronics.dk-a28
    • A29: RES 680 OHM 5% 1/4W AXIALelectronics.dk-a29
    • A30: RES 220 OHM 5% 1/4W AXIALelectronics.dk-a30
    • A32: SWITCH SLIDE DIP SPDT 50MA 24Velectronics.dk-a32
    • A37: LED BAR GRAPH 10SEG 570NM GRNelectronics.dk-a37

    Tools

    Soldering iron, Wire cutters

    Torque

    —

    Time

    —

    After

    17

    Source

    github.com

19. 19

    Assemble the brain board, mount the Pi and mate the boards

    Fit R11, R25-R29, R31-R35; switch SW1 (direction per footprint); LED array U6; J22/J23 ribbon headers (gaps to silkscreen); J25 3x4, J24 shrouded 1x6 (gap to the right), J30 8x1; J26 and C32 on the back (trim C32 leads); J27-J29; the E-stop and TX/RX LED parts Q2-Q6, R16-R23, R36-R38, C33, C34, D8, D9 (BJT and diode polarity). Mount the Pi with M2.5 x 20 mm standoffs and connect its GPIO ribbon to J22. Mate brain board onto motor board with M2.5 x 10 mm standoffs. For a Pi 5, power the Pi through a USB-C cable soldered to the motor board's 5 V and GND test points.

    CHECKBrain board sits level on the motor board; the ribbon is keyed to J22; Q/D orientation matches Figure 4.5.

    Parts in

    • OSR Brain Board PCB v2.0.3 (gerber zip)electronics.pcb-brain-board
    • Raspberry Pi 3, 4 or 5 (any RAM) + microSD card; only the Pi 5 can run the RoboClaw serial link and Bluetooth at the same timecompute.raspberry-pi
    • Raspberry Pi GPIO ribbon cable (Pi to J22)cable.rpi-ribbon
    • USB-C cable with power/ground broken out (Raspberry Pi 5 only; feeds the Pi from the board's 5 V test points)cable.usbc-power-breakout
    • Metric M2.5 standoff kit (30, 20, 15, 12, 10, 6 mm lengths used on the PCBs)fastener.m2-5-standoff-kit

    Tools

    Soldering iron

    Torque

    —

    Time

    —

    After

    18

    Source

    github.com

20. 20

    Bench-test motors and configure the RoboClaws

    Safety · human-verified required

    Secure the board and lay the six wheel/motor assemblies around it on their correct headers, wheels free to spin. Power up. Per RoboClaw over USB in Motion Studio: update firmware; General Settings: Control Mode `Packet Serial`, enable Multi-Unit, address 128/129/130, baud `115200`, Encoder 1/2 `Quadrature`, Max Main Battery 18.5 V, Min 11.5 V. PWM tab: enable Space Bar Stop All, move each slider slowly; set `M1/M2 Reverse` or encoder invert until positive PWM spins the wheel forward and counts up. Velocity Settings: Autotune M1 and M2 with wheels off the ground. Then Device > Write Settings. Cut power before touching any wiring.

    CHECKEach RoboClaw shows Model 2x7a, Logic 5 V, Main Battery 11.5-16.7 V; every motor spins the right way with rising encoder counts; settings persist after a power cycle.

    This step can hurt a person or ruin parts. Its instructions need sign-off by a human who has done it before relying on them. Stop and ask if anything differs from what you see.

    Parts in

    • RoboClaw 2x7A motor controller (one per two drive motors)electronics.roboclaw-2x7a
    • 5203 Series Yellow Jacket Planetary Gear Motor (26.9:1, 24mm length 8mm REX shaft, 223 RPM, 3.3-5V encoder)actuator.yellow-jacket-5203-223rpm

    Tools

    Basicmicro Motion Studio + USB RoboClaw Windows driver, Micro-USB cable, Bench supply or charged battery

    Torque

    —

    Time

    —

    After

    19, 06, 04, 05

    Source

    github.com

21. Integration
    21

    Integrate rocker-bogies, wheels, corners and wiring

    Mount the PCB stack on the bottom plate. Slide a 32 mm ID spacer onto each rocker-bogie axis, feed the cables then the axis through the body plate hole and pillow blocks, and secure with another spacer and a 2-hole flat beam. Attach the differential legs to the 45-degree brackets (M4x8). With a helper, flip the rover: fit the middle motors (3 button screws to the U-channel, 4 socket screws for the clamp), then each corner assembly to its servo output bracket with 3 socket screws, correct side. Plug PCI-E and servo DuPont connectors into the silkscreen-labelled headers. Use blue threadlocker on screws that can vibrate loose.

    CHECKContinuity checks pass through every joint; both rocker-bogies rotate freely when the wheels are lifted; every connector sits in its labelled header.

    Parts in

    • 1506 Series 32mm ID Spacer (36mm OD, 6mm Length) - 2 Packstructure.spacer-32id-6mm
    • 1102 Series Flat Beam (2 Hole, 16mm Length) - 2 Packstructure.flat-beam-2h-16
    • 1120 Series U-Channel (2 Hole, 72mm Length) (6 for the wheels + 2 for the body)structure.u-channel-2h-72
    • 1401 Series 2-Side, 2-Post Clamping Mount (43mm Width, 36mm Bore)structure.clamping-mount-43-36
    • 1501 Series M4 x 0.7mm Standoff (6mm OD, 8mm Length) - 4 Packfastener.standoff-m4-8
    • 1500 Series Plastic Spacer (6mm ID x 8mm OD, 1mm Thickness) - 12 Packfastener.plastic-spacer-6x8x1
    • M4 x 0.7 hex nut (7mm hex), zinc plated - 25 Packfastener.m4-nut-25
    • M4 x 16mm button head screw - 25 Packfastener.m4x16-button-25
    • Blue (removable) threadlockerother.threadlocker-blue

    Tools

    Hex keys, Multimeter, A helper

    Torque

    —

    Time

    —

    After

    15, 11, 13, 20

    Source

    github.com

22. 22

    Fit the body plates

    Fit the laser-cut plates with low-profile button screws and nuts on the inside so nothing falls out while driving (screws.md counts 34 M4x16 button screws for the plates). Hinge the top plates, mount the toggle switch and power meter in the back plate.

    CHECKAll plates are fixed, the top plates swing on their hinges, and the switch and meter are reachable from outside.

    Parts in

    • Bottom plate (bottom_plate.dxf; PCB standoff holes)laser.bottom-plate
    • Side plate (side_plate.dxf; one file, cut two)laser.side-plate
    • Gap slat (gap_slat.dxf; one file, cut two)laser.gap-slat
    • Top front plate (top_front.dxf; optional mission-patch engraving PDFs)laser.top-front
    • Top rear plate (top_rear.dxf)laser.top-rear
    • Front plate (front_plate_standoff.dxf)laser.front-plate
    • Back plate (back_plate_standoff.dxf; switch hole and power-meter cut-out)laser.back-plate
    • M4 x 16mm button head screw - 25 Packfastener.m4x16-button-25
    • M4 x 0.7 hex nut (7mm hex), zinc plated - 25 Packfastener.m4-nut-25

    Tools

    Hex keys, Nut driver

    Torque

    —

    Time

    —

    After

    21, 03

    Source

    github.com

23. Software
    23

    Test serial to all three RoboClaws

    With the rover powered: `cd ~/osr_ws/src/osr-rover-code/scripts`, then `python3 roboclawtest.py 128`, `python3 roboclawtest.py 129`, `python3 roboclawtest.py 130`. If one hangs or returns zeros, re-check address, baud and Multi-Unit mode on every controller, power-cycle, and test one controller at a time. Optionally `python3 test_ina260.py` (address 0x45).

    CHECKEach address prints 'Connected to /dev/serial0', a 'USB Roboclaw 2x7a' version string, encoder counts and main battery voltage.

    Parts in

    —

    Tools

    —

    Torque

    —

    Time

    —

    After

    09, 22

    Source

    github.com

24. Bring-up
    24

    Calibrate the corner servos

    Safety · human-verified required

    Put the body on a box. Unscrew the M3 screw holding each corner to its servo shaft and detach the corners. `cd ~/osr_ws/src/osr-rover-code/scripts` and run `python3 calibrate_servos.py 0 150` then 1, 2, 3 (back right, front right, front left, back left). Re-attach the corners with a drop of blue threadlocker, then trim each with e.g. `python3 calibrate_servos.py 0 160` until the wheel points straight, lifting the corner so it turns freely. Copy `ROS/osr_bringup/launch/osr_launch.py` to `osr_mod_launch.py` if it does not exist and set `centered_pulse_widths` to your four values. Keep hands clear: servos move as soon as a command is sent.

    CHECKAll four wheels point straight ahead at their recorded values; the list in osr_mod_launch.py holds those four numbers.

    This step can hurt a person or ruin parts. Its instructions need sign-off by a human who has done it before relying on them. Stop and ask if anything differs from what you see.

    Parts in

    • 2000 Series Dual Mode Servo (25-2, Torque) (corner steering)actuator.servo-2000-25-2
    • Blue (removable) threadlockerother.threadlocker-blue

    Tools

    2.5 mm hex key

    Torque

    —

    Time

    —

    After

    23

    Source

    github.com

25. 25

    Map the gamepad and first drive

    Safety · human-verified required

    Plug in the gamepad dongle, run `ros2 run joy joy_node` and in a second terminal `ros2 topic echo /joy` to find the axis/button indices; put them in `enable_button`, `axis_linear.x`, `axis_angular.yaw`, `axis_angular.pitch` in osr_mod_launch.py with `scale_linear`, `scale_angular` and `scale_linear_turbo` at 0.05. With the wheels off the ground, run `ros2 launch osr_bringup osr_mod_launch.py` and drive while holding the enable button. Then raise the scales (turbo = drive_no_load_rpm x 2pi/60 x 0.075 m; normal about 0.75 of that; angular = linear / 0.45 m). The rover is fast and strong enough to injure: drive slowly near people.

    CHECKWheels spin and steer in the commanded directions (flip the sign of a scale factor if reversed); only one or two start-up 'Current Error' messages appear; the rover stops when the enable button is released.

    This step can hurt a person or ruin parts. Its instructions need sign-off by a human who has done it before relying on them. Stop and ask if anything differs from what you see.

    Parts in

    • USB gamepad or RC transmitter with USB dongle (Xbox controller, or Spektrum WS2000 + DXs)other.gamepad

    Tools

    —

    Torque

    —

    Time

    —

    After

    24

    Source

    github.com

26. 26

    Optional: start the rover code at boot

    Only after manual launch works: in init_scripts/, `sudo ln -s $(pwd)/launch_osr.sh /usr/local/bin/launch_osr.sh`, `sudo ln -s $(pwd)/osr_paths.sh /usr/local/bin/osr_paths.sh`, `sudo cp osr_startup.service /etc/systemd/system/osr_startup.service`, `sudo chmod 644 /etc/systemd/system/osr_startup.service`, set User/Group in the unit file, then `sudo systemctl enable osr_startup.service`. Stop the service before recalibrating or launching by hand.

    CHECK`sudo systemctl status osr_startup.service` is active after a reboot and the rover responds to the gamepad without SSH.

    Parts in

    —

    Tools

    —

    Torque

    —

    Time

    —

    After

    25

    Source

    github.com

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