Atlas car v2

The second Atlas Autoware car: a Traxxas Slash 4x4 with a Holmes Hobbies Puller Pro 540 motor, a SICK TiM561 lidar and a LUCID Triton camera, rebuilt so that almost nothing is wired by hand. Two custom circuit boards stack on a carbon-fibre-printed deck:

• Drive board (ATLAS-DRV-1). The ESC (VESC firmware, same UART commands as car 1), a battery protector for a built-in 4S3P 18650 pack, USB-C charging, the servo supply, the lidar's power switch and a USB hub.
• Brain board (ATLAS-BRN-1). A Jetson Orin Nano carrier forked from Antmicro's open-source design, with PoE for the camera and a second Ethernet port for the lidar.

Day to day the car needs one USB-C cable: a 65 W laptop charger charges it, and a laptop on the same port reaches the Jetson, the ESC and the serial console.

What is in here

folder	what
docs/	ARCHITECTURE.md (the whole design and why), SOFTWARE.md (what runs on the boards), FLASHING.md (programming the assembled boards), TPS25751_CONFIG.md (USB-C charger settings), PACK_BUILD.md (building the 18650 pack), MEASURE_FIRST.md (chassis numbers to check before printing), COMPLETE_CAR.md (the parts that finish the car), WIRING.md (every cable run and its length)
boards/drive/, boards/brain/	the two boards: design.py is the circuit, layout.py the placement and hand-drawn copper, and the KiCad schematics and layouts are generated from them
boards/stack/	the pin map of the connector between the two boards, used by both
boards/tools/	the scripts that build, route and check the boards
boards/*/out/fab/	Gerbers, drill files, pick-and-place and BOM for ordering
firmware/vesc/	the VESC hardware target for the drive board, build.sh, and a prebuilt image in prebuilt/
software/jetson/	the atlas command, services and settings for the Jetson (system/install.sh), with tests
software/ros2/	atlas_power: battery, E-stop, charging and lidar power in ROS 2
mech/	the printed kit: kit.py (deck, pods, mounts, pack box) and extras.py (stack canopy, bench stand, plugs and cable paths), the STL/STEP files, renders and its own README
sim/	circuit and thermal checks run on the finished schematics, with their own README
bom/	the parts list with prices and the cost summary
share/	pictures for posting; car_scene.py and render_car.py render the whole car

Cost

From bom/cost_summary.md (prices from September 2026):

	USD
Drive board: 5 boards, 1 of them assembled	525.70
Brain board: 5 boards, 1 of them assembled	563.90
18650 pack materials	134.20
Camera lens	144.00
Charger, cable, fan, thermal pad, hardware, antennas	124.35
New purchases	1,492.15
Jetson dev kit and NVMe (already on the purchase list)	459.00
Car 2 total	1,951.15
If needed: M12 camera cable ($30), spot welder ($304.51)	up to 2,285.66

The carbon-fibre filament and the aluminium heat spreader (SendCutSend credit) are not in these numbers because the team already has them.

Status

On 27 September 2026 the design is finished and nothing has been ordered. Later that day the whole car went into one model, with every plug and cable. That found two things that could not have been assembled as drawn, now fixed, and added a canopy over the boards with the Wi-Fi antennas and a bench stand (docs/COMPLETE_CAR.md).

• Both boards are routed. KiCad's DRC finds no unconnected nets and no clearance errors on either of them. What it still lists is minor: silkscreen warnings on both boards, one 0.2 mm track end on the drive board, and on the brain board the footprint-library differences that come with Antmicro's design and the courtyard and hole overlaps Antmicro excluded.
• The stack header matches on both boards: all 40 pins carry the same net at the same place, and the brain board's corner holes sit over the drive board's (boards/tools/check_stack.py).
• The precharge simulation changed the precharge resistors. The bulk capacitors changed too: the first choice was tall enough to hit the brain board's SSD (sim/README.md).
• The printed kit passes its interference checks. Print the two fit coupons first.

What to check before ordering, and the layout choices that are not obvious from the schematics, are at the end of docs/ARCHITECTURE.md.

Rebuilding

• Boards: KiCad 10 and Python 3. boards/tools/run_kicad.sh runs every step (schematic, board, routing export and import, DRC, renders, fabrication files). boards/tools/run_kicad.sh drc-drive fab-drive checks the finished drive board and writes its fabrication files. Careful with pcb-drive: it builds the board again from the placement, without the routing. The routing itself was done with Freerouting 1.9 and finished with boards/tools/mazeroute.py.
• Printed kit: pip install cadquery ezdxf matplotlib, then python3 mech/kit.py and python3 mech/extras.py.
• Whole-car renders: python3 share/car_scene.py, then python3 share/render_car.py -- car_front_left car_exploded with Blender 4.2's bpy module (Python 3.11, pip install bpy==4.2.0) and the board models from run_kicad.sh glb-drive glb-brain.
• Simulations: ngspice and Python with numpy, scipy and matplotlib; sim/run_all.sh.
• Firmware: firmware/vesc/build.sh (clones VESC 6.06, adds the two target files, builds; needs arm-none-eabi-gcc). A build of the committed sources is in firmware/vesc/prebuilt/.
• Jetson tools: sudo software/jetson/system/install.sh on the car; tests with cd software/jetson && python3 -m pytest tests (needs pytest).

Licenses

The brain board is derived from Antmicro's Jetson Orin Baseboard (Apache-2.0); its schematic and board keep Antmicro's notices, and boards/brain/vendor/antmicro/fetch.sh downloads the original. The VESC hardware target is derived from the VESC firmware (GPL-3.0), so those two files are GPL-3.0.