Build Stanford Pupper (v1)

Steps

20

Subassemblies

8

Hands-on time (sum)

—

Critical path

—

Your progress · this device

—

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

1. Fabrication
   01

   Get the STLs, carbon fiber parts and PCBs

   Download the STLs from the BOM's Google Drive folder. Buy the carbon fiber set (Great3D was the upstream source) or have the parts routed. Order the power distribution board from JLCPCB with the Gerbers.zip from Pupper-Raspi-PDB (xt60cable branch): 2 layers, quantity 5, 2 oz copper ('super important'), everything else default.

   CHECKYou have 7 STL files, 2 carbon plates plus 4 upper and 4 lower legs, and 2 oz copper bare PDBs.

   Parts in

   • Carbon fiber routed parts: top and bottom plates (1.5 mm), 4 upper legs (3 mm), 4 lower legs (2 mm)structure.cf-parts
   • Custom power distribution PCB (Pi hat), pack of 5; 2 layers, 2 oz copperelectronics.pdb
   • Carbon fiber plate "Top"cf.plate-top
   • Carbon fiber plate "Bottom"cf.plate-bottom
   • Carbon fiber upper legcf.upper-leg
   • Carbon fiber lower legcf.lower-leg

   Tools

   —

   Torque

   —

   Time

   —

   After

   Start

   Source

   docs.google.com

2. Hips
   02

   Hip step 1: install the servo disc on the ab/adduction servo (x4)

   Put a horn on the servo, turn it to neutral, remove the horn. Seat the disc with its holes at roughly the 45° marks, add a dab of Loctite to the M3x6 socket screw and drive it in until the disc seats. Poorly made discs take a lot of torque at first; stop when the torque rises again at full seating or you can break the servo.

   CHECKDisc is fully seated with holes at about 45° while the servo is at neutral; the screw is snug, not forced.

   Parts in

   • JX CLS6336 servo (3 per leg); upstream recommends buying a few sparesactuator.jx-cls6336
   • 25T disc servo spline, ab/adduction connector (pack of 5, 4 used)structure.servo-disc-25t
   • M3 x 6 alloy steel socket head screw (pack of 100; 16 carbon fiber to body, 4 servo discs)fastener.m3x6-socket
   • 25T servo arm (horn)structure.servo-arm-25t

   Tools

   2.5 mm hex driver, Loctite

   Torque

   —

   Time

   —

   After

   Start

   Source

   pupper.readthedocs.io

3. Software
   03

   Flash Raspbian and the RPI-Setup files

   Flash 2019-09-26-raspbian-buster-lite with Etcher (fallback: 2020-02-13-raspbian-buster-lite from downloads.raspberrypi.org). Copy the latest RPI-Setup release (github.com/Nate711/RPI-Setup) onto the boot partition, overwriting conflicts. Boot the Pi, set your computer to a static 10.0.0.X / 255.255.255.0 on Ethernet, `ssh pi@10.0.0.10` (password `raspberry`), run `rw`, set up Wi-Fi with `sudo raspi-config`, then `sudo ./install_packages.sh` (pick a new IP and hostname) and `sudo ./time_sync.sh`.

   CHECKThe prompt ends with (rw) after `rw`, and `ping www.google.com` gets replies.

   Parts in

   • microSD card for the Pi (32 GB recommended; listed on the Tools tab)compute.microsd

   Tools

   balenaEtcher, Ethernet cable, USB-C 5 V >= 3 A Pi power supply

   Torque

   —

   Time

   —

   After

   Start

   Source

   pupper.readthedocs.io

4. Fabrication
   04

   Print the body supports, Pi case and hips

   Print in PLA or PETG at 0.2-0.4 mm layer height and more than 50% infill: FrontFront, FrontBack, BackFront, BackBack, picase, and 4 each of HipInsideFDM and HipOutsideFDM (a 5th of each as a spare is suggested).

   CHECK4 body pieces, 1 Pi case, 4 inner and 4 outer hips; the bearing holes in FrontFront and BackFront accept an MR693 bearing with a press fit.

   Parts in

   • Body support "Front1" (FrontFront.stl), holds 2 hip bearingsprinted.front-front
   • Body support "Front2" (FrontBack.stl)printed.front-back
   • Body support "Back1" (BackFront.stl), holds 2 hip bearingsprinted.back-front
   • Body support "Back2" (BackBack.stl)printed.back-back
   • Raspberry Pi case (picase.stl)printed.picase
   • Inner hip (HipInsideFDM.stl); upstream suggests a 5th as a spareprinted.hip-inside
   • Outer hip (HipOutsideFDM.stl); upstream suggests a 5th as a spareprinted.hip-outside

   Tools

   FDM printer, or a print service (upstream used 3D Hubs: SLS PA12 ~$180, FDM PLA/PETG ~$80)

   Torque

   —

   Time

   —

   After

   01

   Source

   docs.google.com

5. Electronics
   05

   PCB steps 1-4: headers, Vbat/5 V pins and XT60

   Solder the 12 three-pin servo headers (tack the signal pins nearest the 2x20 header first, then ground and +). Insert the 2x20 header from the bottom so it sits on the Pi, solder from the top. Add 1x2 pins at 'Regulated 5V' and at 'Vbat' (skip Vbat pins if you cannot crimp Dupont/JST). Solder the XT60 pigtail from the top, matching the + and - labels.

   CHECKAll joints shiny and complete; the XT60 polarity matches the silkscreen.

   Parts in

   • Custom power distribution PCB (Pi hat), pack of 5; 2 layers, 2 oz copperelectronics.pdb
   • Male header pins for the PDB servo connectors (pack of 50 strips)electronics.header-pins
   • Raspberry Pi 2x20 female stacking header for the PDB (pack of 5 listed, 1 used)electronics.pi-header
   • XT60 connector pigtail (pack of 2, 1 used)cable.xt60

   Tools

   Soldering iron (>= 60 W recommended), Vise

   Torque

   —

   Time

   —

   After

   01

   Source

   pupper.readthedocs.io

6. Software
   06

   Install StanfordQuadruped and the joystick service

   On the Pi: `git clone https://github.com/stanfordroboticsclub/StanfordQuadruped.git`, `cd StanfordQuadruped`, `sudo bash install.sh` (installs numpy, transforms3d, pigpio, pyserial, PupperCommand, PS4Joystick and pigpio v74, and enables robot.service). Unplug the battery 30 s and power back up. Pair the PS4 controller: hold Share + PS until it double-flashes.

   CHECK`sudo systemctl status joystick` shows 'Connected to Bluetooth Controller'; `sudo systemctl status robot` shows no failure (fix with `sudo systemctl restart robot`).

   Parts in

   • Sony DualShock 4 (PS4) wireless controllerelectronics.ps4-controller

   Tools

   —

   Torque

   —

   Time

   —

   After

   03

   Source

   pupper.readthedocs.io

7. Hips
   07

   Hip step 2: M3 heat-set insert in each inner hip

   Safety · human-verified required

   Tapered side down, press the insert with just the weight of the iron at about 260 °C, 1 mm at a time, lifting the iron between pushes so it does not stick. Hot tip: use a stand.

   CHECKInsert sits flush and square; an M3 screw threads in without the insert turning.

   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

   • M3 short heat-set insert (pack of 100; 16 body pieces, 4 inner hips)fastener.m3-insert
   • Inner hip (HipInsideFDM.stl); upstream suggests a 5th as a spareprinted.hip-inside

   Tools

   Soldering iron at ~260 °C (500 °F)

   Torque

   —

   Time

   —

   After

   04

   Source

   pupper.readthedocs.io

8. Body
   08

   Body steps 1-2: inserts and hip bearings in the body pieces

   Safety · human-verified required

   Press 4 M3 heat-set inserts into each of the 4 body pieces (2 top, 2 bottom), same method as the hips. Press 2 MR693 bearings into FrontFront and 2 into BackFront.

   CHECK16 inserts flush; 4 bearings seated and spinning freely.

   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

   • M3 short heat-set insert (pack of 100; 16 body pieces, 4 inner hips)fastener.m3-insert
   • Body support "Front1" (FrontFront.stl), holds 2 hip bearingsprinted.front-front
   • Body support "Front2" (FrontBack.stl)printed.front-back
   • Body support "Back1" (BackFront.stl), holds 2 hip bearingsprinted.back-front
   • Body support "Back2" (BackBack.stl)printed.back-back
   • MR693-ZZ bearing 3 x 8 x 4 mm, ab/adduction axle (pack of 10, 4 used)structure.mr693-bearing

   Tools

   Soldering iron at ~260 °C, Arbor press or vise

   Torque

   —

   Time

   —

   After

   04

   Source

   pupper.readthedocs.io

9. Electronics
   09

   PCB steps 5-7: short test, servo power test, BEC

   Safety · human-verified required

   Continuity-test that XT60 + and - are not shorted, and no signal pin shorts to +, - or another signal. Plug in the 2S LiPo (never more than 8.4 V), plug one servo in (signal wire, usually yellow or white, toward the Pi header), then unplug both. Cut the BEC's input JST, solder or crimp its input to Vbat, and plug its 5 V JST onto the Regulated 5V pins.

   CHECKNo shorts; the single servo powers up without smoke; with the battery in, the BEC output reads 5 V.

   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

   • 5200 mAh 2S LiPo, XT60 (never more than 8.4 V: higher voltage burns the servos)power.lipo-2s-5200
   • 5 V regulator (BEC) for the Pi (pack of 2, 1 used)power.bec-5v
   • JX CLS6336 servo (3 per leg); upstream recommends buying a few sparesactuator.jx-cls6336

   Tools

   Multimeter, Soldering iron or crimper

   Torque

   —

   Time

   —

   After

   05

   Source

   pupper.readthedocs.io

10. Hips
    10

    Hip steps 3-5: disc to inner hip, inner servo, standoffs and horn (x4)

    Mount the inner hip at 90° and tighten the M3x8 flat head through the access holes into the disc. Seat the servo with its shaft in the big round hole: silver M4x10 plastic screws on the left, M3x16 button heads (Loctite) through standoffs on the right. Turn the servo to neutral and fit the horn pointing 45° downward; M3x8 button head on top, M2x8 socket heads in the side clamp, Loctite on all.

    CHECKPlastic screws on one side, M3 screws on the other (as in the photos); horn is at 45° down with the servo at neutral.

    Parts in

    • M3 x 8 alloy steel flat head screw, disc spline to inner hip (pack of 100)fastener.m3x8-flat
    • JX CLS6336 servo (3 per leg); upstream recommends buying a few sparesactuator.jx-cls6336
    • M4 x 10 thread-forming screw for plastic (pack of 25; 32 used: 16 body, 16 servo mounts)fastener.m4x10-plastic
    • M3 x 16 alloy steel button head screw, standoff through servo mounting hole (pack of 100, 16 used)fastener.m3x16-button
    • 20 mm M3 aluminium standoff, leg hub (pack of 20, 16 used)structure.standoff-m3-20
    • 25T servo arm (horn)structure.servo-arm-25t
    • M3 x 8 alloy steel button head screw (pack of 100; ~20 used: hip bearings, servo arms, ball links, feet)fastener.m3x8-button

    Tools

    2 mm hex driver, T20 Torx driver, Loctite

    Torque

    —

    Time

    —

    After

    02, 07

    Source

    pupper.readthedocs.io

11. Legs
    11

    Hip steps 6-7: knee stack and upper link to horn

    On each shoulder bolt: thrust bearing, lower leg, thrust bearing, upper leg, locknut; mirror the order of upper/lower for left and right legs. Align the curved edge of the upper leg with the servo horn and fix it with 2 M3x6 button heads, holding the screw nearest the servo vertical to avoid cross-threading.

    CHECKKnee rotates freely with no axial play; upper leg is fixed to the horn with both screws.

    Parts in

    • M3 shoulder bolt, 4 mm shoulder dia., 12 mm shoulder length, lower leg axlefastener.shoulder-bolt
    • Thrust bearing 4 x 9 x 4 mm, 3-part, knee (pack of 10, 8 used)structure.thrust-bearing
    • Carbon fiber lower legcf.lower-leg
    • Carbon fiber upper legcf.upper-leg
    • M3 locknut (pack of 100; 12 used: ball links, knee stack, feet)fastener.m3-locknut

    Tools

    2 mm hex driver, Wrench for the locknut

    Torque

    —

    Time

    —

    After

    10

    Source

    pupper.readthedocs.io

12. Hips
    12

    Hip steps 8-11: outer servo, horn, join the halves

    Fix the servo in the outer hip with the two plastic screws nearest the spline. Neutral, then horn at 45° (M3x8 first, then M2x8 to clamp). Join inner and outer halves with M3x16 through the outer hip into the standoffs (Loctite, not fully tight yet); plastic screws on the same side, horns at 90° to each other. Add the other 2 standoffs with 4 M3x10 button heads. Mark left and right; compare with the Fusion 360 model if unsure.

    CHECKA rigid hip module with 4 standoffs; the two horns sit 90° apart.

    Parts in

    • Outer hip (HipOutsideFDM.stl); upstream suggests a 5th as a spareprinted.hip-outside
    • JX CLS6336 servo (3 per leg); upstream recommends buying a few sparesactuator.jx-cls6336
    • M4 x 10 thread-forming screw for plastic (pack of 25; 32 used: 16 body, 16 servo mounts)fastener.m4x10-plastic
    • 25T servo arm (horn)structure.servo-arm-25t
    • M3 x 8 alloy steel button head screw (pack of 100; ~20 used: hip bearings, servo arms, ball links, feet)fastener.m3x8-button
    • M3 x 16 alloy steel button head screw, standoff through servo mounting hole (pack of 100, 16 used)fastener.m3x16-button
    • M3 x 10 alloy steel button head screw (pack of 100; 32 standoffs, 4 ball links)fastener.m3x10-button
    • 20 mm M3 aluminium standoff, leg hub (pack of 20, 16 used)structure.standoff-m3-20

    Tools

    T20 Torx driver, 2 mm hex driver, Loctite

    Torque

    —

    Time

    —

    After

    11

    Source

    pupper.readthedocs.io

13. 13

    Hip step 12: check each servo's range by hand

    Unpowered, move each joint through its range.

    CHECKHip goes fully flat on either side; the inner horn goes from 45° up to touching the lower standoff; the outer horn goes from touching the standoff to 45° down.

    Parts in

    —

    Tools

    —

    Torque

    —

    Time

    —

    After

    12

    Source

    pupper.readthedocs.io

14. Legs
    14

    Hip steps 13-15: extension rod and parallelogram linkage

    Thread the rod ends on equally until the hole centres are 123.5 mm apart. Screw the rod to the outer servo horn from the inside with an M3x8 button head. Fix the other end to the lower leg with an M3x10 button head through the carbon and the rod end, and a locknut.

    CHECKHorn, extension rod, upper leg and the top of the lower leg form a parallelogram (the docs' photo correction shows a rod that is too short).

    Parts in

    • Threaded rod for the extension rod (pack of 10, 4 used)structure.threaded-rod
    • 3.0 x 20 mm rod end / ball link (pack of 5; 8 used)structure.ball-end
    • M3 x 8 alloy steel button head screw (pack of 100; ~20 used: hip bearings, servo arms, ball links, feet)fastener.m3x8-button
    • M3 x 10 alloy steel button head screw (pack of 100; 32 standoffs, 4 ball links)fastener.m3x10-button
    • M3 locknut (pack of 100; 12 used: ball links, knee stack, feet)fastener.m3-locknut

    Tools

    2 mm hex driver, Wrench, Calipers

    Torque

    —

    Time

    —

    After

    13

    Source

    pupper.readthedocs.io

15. Body
    15

    Body steps 3-4: fasten the hips and the bottom plate

    Fix two hip assemblies to BackBack and two to FrontBack with the plastic screws, then drive M3x8 button heads through the bearings in FrontFront and BackFront into the hip inserts. Screw both leg/body assemblies to the bottom carbon plate with 16 M3x6 screws.

    CHECKAll four hips abduct freely on their bearings and both ends sit flat on the bottom plate.

    Parts in

    • M4 x 10 thread-forming screw for plastic (pack of 25; 32 used: 16 body, 16 servo mounts)fastener.m4x10-plastic
    • M3 x 8 alloy steel button head screw (pack of 100; ~20 used: hip bearings, servo arms, ball links, feet)fastener.m3x8-button
    • Carbon fiber plate "Bottom"cf.plate-bottom
    • M3 x 6 alloy steel socket head screw (pack of 100; 16 carbon fiber to body, 4 servo discs)fastener.m3x6-socket

    Tools

    T20 Torx driver, 2 mm hex driver

    Torque

    —

    Time

    —

    After

    08, 14

    Source

    pupper.readthedocs.io

16. 16

    Body step 5: Pi case

    Press 4 M2.5 inserts into the Pi case, screw the Pi 4 down with M2.5 socket heads, and stick the case to the bottom plate with Dual Lock.

    CHECKPi is rigid in the case and the case holds on the plate when the robot is lifted.

    Parts in

    • Raspberry Pi case (picase.stl)printed.picase
    • M2.5 short heat-set insert for the Pi case (pack of 100, 4 used)fastener.m2p5-insert
    • M2.5 x 5 socket head screw, Pi to case (pack of 100, 4 used)fastener.m2p5x5-socket
    • Raspberry Pi 4 (2 GB listing linked)compute.rpi4
    • 3M Dual Lock SJ3550, 1 in x 4 ft (8 in used) to hold the Pi case and battery; optionalother.dual-lock

    Tools

    Soldering iron, 2 mm hex driver

    Torque

    —

    Time

    —

    After

    15

    Source

    pupper.readthedocs.io

17. Electronics
    17

    Body step 7: plug the 12 servos into J1-J12

    Stack the PDB on the Pi and plug each servo into its J1-J12 header following the docs' mapping photo. Signal pins always face the Pi header.

    CHECK12 servos plugged in per the mapping, every signal wire toward the Pi header.

    Parts in

    • Custom power distribution PCB (Pi hat), pack of 5; 2 layers, 2 oz copperelectronics.pdb
    • JX CLS6336 servo (3 per leg); upstream recommends buying a few sparesactuator.jx-cls6336

    Tools

    —

    Torque

    —

    Time

    —

    After

    16, 09

    Source

    pupper.readthedocs.io

18. Bring-up
    18

    Calibrate the 12 servo offsets

    Safety · human-verified required

    Robot on a stand, 2S LiPo in. SSH in and run `rw`, `sudo systemctl stop robot`, then `cd StanfordQuadruped`, `sudo pigpiod`, `python3 calibrate_servos.py`. Follow the prompts, aligning joint centres (not link edges) to horizontal or vertical for each of the 12 motors; the script writes the offsets. Then `sudo systemctl start robot`. Servos move under power: keep fingers out of the linkages.

    CHECKEvery joint reaches the prompted horizontal/vertical pose (if not, a disc or horn was mounted wrong) and the script finishes for all 12 servos.

    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

    • 5200 mAh 2S LiPo, XT60 (never more than 8.4 V: higher voltage burns the servos)power.lipo-2s-5200

    Tools

    Stand that keeps the feet off the table

    Torque

    —

    Time

    —

    After

    17, 06

    Source

    pupper.readthedocs.io

19. 19

    First run: activate and trot

    Safety · human-verified required

    Optional for slippery floors: bolt a cushioning washer to each foot hole (M3x8, washer, locknut). Fit the top plate. Plug in the battery (the code starts on boot), pair the controller, press L1 to activate, R1 to toggle rest/trot; left stick translates, right stick pitch/yaw, D-pad height/roll, X three times to hop. Use a LiPo alarm and stop when a cell is below about 3.6 V.

    CHECKController light goes dim green on bind and bright green after L1; the robot stands and trots in place on R1.

    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

    • M3 x 8 alloy steel button head screw (pack of 100; ~20 used: hip bearings, servo arms, ball links, feet)fastener.m3x8-button
    • M3 locknut (pack of 100; 12 used: ball links, knee stack, feet)fastener.m3-locknut
    • M3 washer for the foot (pack of 100, 4 used)fastener.m3-washer
    • Cushioning washer used as a foot (pack of 10, 4 used)other.cushion-washer
    • Carbon fiber plate "Top"cf.plate-top

    Tools

    —

    Torque

    —

    Time

    —

    After

    18

    Source

    pupper.readthedocs.io

20. Options
    20

    Optional: BNO080 IMU via Teensy LC

    The BOM lists an optional IMU setup (BNO080 breakout read by a Teensy LC connected to the Pi; src/IMU.py reads it over serial). The build guide gives no wiring or firmware steps for it.

    CHECKOnly if you add it: IMU data arrives on the Pi's serial port.

    Parts in

    • SparkFun VR IMU breakout BNO080 (optional IMU setup)sensor.bno080
    • Teensy LC, IMU-to-Pi bridge (optional IMU setup)electronics.teensy-lc

    Tools

    —

    Torque

    —

    Time

    —

    After

    19

    Source

    docs.google.com

Progress is stored in this browser only (localStorage). Nothing is sent anywhere.