Parts list and cost

• Tax and shipping.
• The camera and the 360 camera (from the client's stock).
• Adhesive for the lower shell, fenders and trim and for the in-house shell's splice strips and skirt halves, and paint or vinyl for the accents.
• The print service version of the shell (the top shell and both skirts in one piece each, about $520, est.), if they are not printed in-house.
• Making the DXF files (part of the prototype estimate).
• Labour, printer time and laser time.
• In the shop stock total, the stock itself: wire, connectors, heat shrink, ties, fuses, USB cables, the chassis PETG, the 0.125 in aluminum sheet and the acrylic sheet ($211.59 if bought new).

The wiring, firmware and acceptance plan follow R4, with the 2026-10-07 electronics changes, the mast and the 2026-10-30 additions (see How S1 goes together). The Orange Pi software drives the motors, servos and I2C boards directly, as on the current car.

S1 is the same car as R4, built a much simpler way. Every function stays:

• the computer (it drives the motors and servos and runs the I2C bus straight off its own pins, as on the current car);
• the LiDAR, eight ToF sensors, eight Sharp sensors, and the camera (from the client's stock) on a telescoping mast that lifts it to 55 in and folds down for shipping;
• the two rear gearmotors and two front steering servos;
• the LiFePO4 pair, the E-stop chain and the fans.

What changes is the construction: cut plates, printed parts and catalog motion parts, all bolted together, under a printed two-piece body whose top shell lifts off.

One joint. The frame and the rear bulkhead use one printed corner block; the printed body is held by thumb screws and bonding.

• Corner blocks (12). 12 x 12 x 40 mm, with one vertical and one horizontal M4 hole 20 mm apart, so the two bolts never cross. Each is an M4 x 25 with a nyloc nut. Four join the floor to the walls, four the walls to the deck, two the rear bulkhead to the deck, and one per side joins each fork leg to its top plate.
• Two M4 lengths cover every nut joint: M4 x 25 through a block or a rear bearing pair, M4 x 20 everywhere else.

Access from outside. No nut needs a hand inside a closed box.

• The battery bay is assembled with its top open. That covers the floor-to-wall blocks, the servo stands and the nose bolts.
• The deck is the bay's lid. It bolts to ledge blocks outside the side walls, and those nuts sit under the deck overhang.
• The top shell lifts straight off after four thumb screws, so the whole deck is open for wiring and service.

The assemblies:

• Chassis: floor (FL), two side walls (SW), two nose fascias (NSF, NSR) and two side cassettes (SSC).
  • Floor. One flat 0.125 in plate, trimmed to the nose outline. Cut into it: the battery strap slots, the mast socket's and winch's bolt holes and the two servo stands' bolt holes.
  • Side walls. The two walls are the same flat part. Each stands on the floor's edge and is held by two corner blocks inside the bay; the noses tie floor and walls at both ends. Each wall carries the gearmotor face holes, the side cassette's flange holes and lead opening, and a slot the steering horn and tie rod swing through.
  • Nose fascias. Printed in PETG with 4 mm walls: face, two 35° facets, sides and closing walls, a tab inside each side wall, a floor flange and top and bottom skins. Each carries three sensor cassettes; the front one also carries the intake grille with the filter and the 40 mm fan behind it, on the same four screws.
  • Side cassettes. Printed housings that carry stations 2 and 6 out to the shell's side; each flange bolts to the wall with four M4.
• Deck (DK). One flat plate with both front steering wings in the same piece.
  • It rests on the walls and noses, and bolts to two ledge blocks per side under its overhang.
  • Every board bolts straight to it on short spacers. A 38 mm vent lets the intake fan's air rise from the lower bay.
  • The rear bulkhead stands on it on two corner blocks and holds the exhaust fan, the battery disconnect and the charge port, each sealed to the top shell by a TPU boot.
  • The towers, the cup, the mast's deck collar and the four shell latch posts bolt to it.
  • Electronics changes from R4 (2026-10-07):
    • Three bucks instead of four. The sensors and fans share the computer's 5 V 10 A buck. Each Sharp gets a 10 µF capacitor at the sensor, as its data sheet advises.
    • The drive relay switches the motor driver, so the E-stop stops the wheels. The relay is a 40 A automotive relay in a socket, behind its own 15 A fuse.
    • The Orange Pi's own GPIO and I2C drive the servos, read the slow I/O and run the I2C bus, as on the current car. That replaces the USB-to-I2C bridge, the servo board and the I/O expander, and since 2026-10-20 the Pico too.
• Body, two-piece. The printed top shell is the roof. It sits on the lower shell at z 194 over a TPU gasket and is held by four M4 thumb screws through its sides into latch posts on the deck edge; with them out it lifts straight off.
  • The roof parts stand on printed towers bolted to the deck and pass up through the shell, each through a hole that clears its top: the LD19, the E-stop, the USB charging socket, the 360 camera cup and the mast. A TPU boot round each presses up on the shell's skin; the mast and the E-stop right behind it share one.
  • The LD19's square base screws down with three M2 x 6 to a shelf on its tower 22.2 mm under the roof and rises through a square opening, its top flush with the roof, so its whole round head stands above it at the front of the flat roof. Its scan plane, 4.8 mm over the roof, clears everything but the mast, which hides 17° straight back: the E-stop stands in that slice, the USB socket's cap sits in a pocket level with the roof, and the cup's rim just under it.
  • The lower shell is the two side skirts between the wheel bays, bonded to the side cassettes. At the ends the nose fascias, and over the rear wheels a ledge on each rear quarter, carry the gasket.
  • The fenders are narrower than v4 (out to x 222, was 228), roll tighter and curve down hard over the wheel at both ends; they still cover the deck wing and the kingpin collar and clear the tire at full lock.
• Telescoping mast. Five nested 6061 tubes from the shop's stock, 1-3/4 down to 3/4 in OD, .058 in wall, 330 mm each. The outer one stands in a printed floor socket and is clamped by a printed deck collar.
  • A self-locking 12 V worm gearmotor on the floor winds one cable. Cascade cables over a sheave in each stage's top collar raise every stage together; gravity lowers them, and the worm holds any height with the power off.
  • Extend and retract limit switches, each with a diode across it, stop the motor only in the direction that reached them. The DRV8871 driver is fed after the drive relay, so the E-stop stops the mast too.
  • Retracted, the top cap is 137 mm over the roof (the camera comes off for shipping and before the shell does). Extended, the camera is at 55 in with 91 mm of overlap in each joint.
• Front steering (two). A centre pivot over each front wheel, turned by a linkage:
  1. Fork. A flat top plate with a 45 mm steering arm and one flat leg inboard of the wheel, joined by a corner block. An M8 x 60 stub axle, head inboard, carries the RUTU wheel on one 10 mm spacer; its nyloc outboard clamps leg, spacer and bearing races.
  2. Kingpin. A goBILDA Sonic Hub's four screws clamp the fork top plate to a 56 mm REX kingpin. A thrust spacer carries the deck's weight from the lower bearing to the hub.
  3. Bearings. Two KFL08 flange bearings sandwich the deck wing on shared bolts; a clamping collar on top keeps the kingpin in when the car is lifted.
  4. Servo. An MG996R stands upright on a printed stand bolted to the floor. A 45 mm horn and a tie rod drive the fork arm; horn and arm are parallel and equal, so the wheel turns exactly as the horn does.
• Rear drive (two). The FIT0185 gearmotor bolts straight to the inside of the wall through its own six M3 face holes, with no bracket.
  1. A 6-to-8 mm jaw coupler drives a 96 mm REX axle. Its rubber spider takes up small misalignment, so the motor shaft carries no wheel load.
  2. The axle runs in two KFL08s that sandwich the crown of a printed bearing block outside the wall, on one shared pair of M4 x 25.
  3. The block is a bridge over the coupler. Its open top and bottom reach the coupler and bearing set screws and the gearmotor face screws.
  4. A goBILDA 1313 Hyper Hub, bolted to the wheel's metal hub on its 32 mm pattern, carries the torque.
• Sensor stations (eight, identical). Each is a cassette: two windows in a 4 mm printed skin, a clear acrylic pane outside, the Sharp and ToF modules inside, and the same four bolts through all three.
• Batteries stand upright on a rubber pad, held by two hook-and-loop straps through the floor slots. They charge in place through the rear charge port.
• Mast. Built on its bench as one unit (see the telescoping mast above). It goes in last, through the deck collar into its floor socket, and comes out first.
• Styled body. The fenders, flares, quarters and trim go on last. How they and the lower shell fix to the frame is not in the model yet, so their adhesive is not counted.

Assembly line. The build runs as stations that work in parallel. Each station hands a finished, checked module to the final line:

• S0 Cut and print: every laser-cut and printed part, deburred, labeled and kitted for the other stations.
• S1 Sensors: all eight sensor stations, in the two nose fascias and the two side cassettes, each checked on the bench.
• S2 Drive: the rear drive on each side wall (motor, jaw coupler, bearing block, two bearings, axle) and the two driven wheels, drilled and hubbed.
• S3 Steering: two single-sided forks with their front wheels on stub axles, two servo stands with centered servos, horns and tie rods, and the kingpin kits.
• S4 Electronics deck: every board and power part on the deck and the rear bulkhead, wired and powered up on the bench.
• S5 Body: the roof towers and cup (LiDAR, E-stop and USB socket fitted), the top shell with its gasket and boots, the lower shell skirts and the styled body parts. A shell printed in-house is bonded first: the six top shell sections on their eight splice strips, each skirt's two halves to its side cassette.
• S6 Mast: the telescoping mast: five tubes with their collars, sheaves and cables, the winch and both limit switches, run end to end on the bench.
• S7 Final line: the battery bay, batteries, deck, steering corners, wheels, mast and top shell, then the power-up and drive tests.

With one person per bench station and two on the final line, a car comes off the line in about 6 hours once the parts are cut and printed. The planning times are estimates, raised on 2026-10-30 for the mast and the two-piece body, until the first car is timed.

• Inventor model: project New Trackless Car, module Trackless Photocar S1 - simplified laser-cut build (10cd1239-2e70-4854-baa8-a782122c23d2). Since 2026-10-30 it holds the two-piece body and the telescoping mast in configuration C1, with the shell printed in-house: 216 items.
  • This flat build replaced the module's first, press-bent S1 draft, which needed a paid bending order. At the owner's direction, the R4 module that occupied this project was archived on 2026-10-06; the project's schematic was kept because S1 uses the same electronics.
  • Client feedback pass, 2026-10-30.
    • Two-piece body: the printed top shell is the roof and lifts off after four thumb screws. The aluminum lids, side panels, front end panel and their 24 lip screws are gone; the rear end panel is a flat 0.125 in bulkhead on two corner blocks.
    • The LiDAR, E-stop, USB socket, 360 camera cup and mast stand on deck towers through the shell, each sealed by a TPU boot.
    • The two red hood lamps (styling, not breakers) are gone; each battery now has a 30 A inline fuse before the disconnect.
    • Narrower front fenders that curve down over the wheels, and rear flares that stop just past the tire: about 40% less material.
    • A telescoping mast to 55 in, TPU seals wherever the body opens, and two GPS configurations (see Configurations).
    • The LiDAR has a clear 360° view: its square base sits on a shelf under the roof, flush with it, and its whole round head stands above; nothing else on the roof crosses its scan plane but the mast, with the E-stop right behind it. The LiDAR in the nose and the GPS box on the roof are gone.
  • Construction pass, 2026-10-07. Each rear axle runs in two KFL08s behind a jaw coupler. Three bucks instead of four, with a 10 µF capacitor at each Sharp. The lids and end panels are 0.063 in aluminum.
  • v4 pass, 2026-10-20.
    • Body joints are bent lips, not blocks: 22 corner blocks are gone, leaving 10.
    • The front roof lid and the rear lid each have one bend; a flat hood lid rests on the side panels' sloped lips.
    • Steering by linkage: each servo stands upright on a printed stand and turns its fork through a 45 mm horn, a tie rod and a 45 mm arm. The goBILDA servo couplers and the printed servo towers are gone.
    • Single-sided forks: one leg inboard of each front wheel, an M8 x 60 stub axle, a thrust spacer under the Sonic Hub and a collar on the kingpin top.
    • Sensors in cassettes: printed nose fascias with three each (the front one with the intake grille, filter and fan), and stations 2 and 6 in printed side cassettes.
    • A printed puck levels the LD19 on the sloped front lid.
    • A printed styled body: shell, fenders, flares, rear quarters and trim.
• Kept from R4: the 400 mm (15.7 in) wheelbase and 360 mm (14.2 in) front track; the 6 in wheels; the eight sensor headings (0, 35, 90, 145, 180, 215, 270 and 325°); the electronics, power and safety layout, apart from the 2026-10-07 changes.
• Checks on the 2026-10-30 model: the solid clash check is clean for every new or changed part, static and at ±35° of steering, in both configurations and both shell prints (the styled panels overlap each other by design, as before); the wiring check passes with no warnings in both.
• Checks on the v4 model (2026-10-20): the solid clash check is clean static and at ±35° of steering; the bolt-path check is clean (corner blocks, stand bolts, the fan stack, side cassette flanges, LiDAR mount screws, station sweeps); the server bounds match apart from three explained items; run_sanity flags only its known exhaust fan and filter heuristic.
• Found while weighing the parts for this list:
  • The rear quarters, rear flares, logo plate and sills are solid in the model (a rear quarter is about 1.19 L). The list prints them at low infill; hollowing them in the model would cut the black PETG roughly in half.
  • The lower shell's and fenders' fixing to the frame, and the mast's bushings and cables, are not modeled. The in-house shell's sections, splice strips and skirt halves are.
• Purchased parts are simplified envelopes. The cut and printed parts carry their real holes and cut-outs. Weights and areas come from random point sampling of the model, within a few per cent.