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Machine-translated by Robotheca from the original in Chinese (opens in a new tab). License: MIT (opens in a new tab).

Atlas Rover Mk.1 V1.0 Detailed Assembly and Wiring Manual

How to Use This Reference Diagram

The reference diagram is used to determine the aesthetic language: brass cage frame, front bumper, dual eye guards, top handle, front light bar, rear speaker position, and side wheel arches.

The electrical design remains based on the V1.0 final version: four N20 motors, four 64T gear wheels, XIAO ESP32C3 chassis control board, two DRV8833 motor drivers, WS2812B external lights, AHCT/HCT data level conversion, external speaker. The PCA9685 is only an optional PWM expansion when the chassis board's GPIO is insufficient.

Components such as TP4056, MAX98357A, and INMP441 are not included in the Mk.1 must-buy list in the reference diagram table.

How to Purchase Brass Materials

Material	Theoretical Quantity	Recommended Purchase	Usage
2.0 mm brass rod	~2.57 m	Recommended to buy 3 m	Main load-bearing frame, bumper, top handle, wheel arches
1.5 mm brass rod	~1.18 m	Recommended to buy 2 m	Eye guards, diagonal braces, lamp brackets, speaker trim
0.8-1.0 mm fine copper/brass wire	~0.6 m	Optional to buy 1 m	Tied welding points, decorative winding; not for main structure

2.0 mm is the main structure and should not be less than 1.8 mm. 1.5 mm is used for detailed shaping and is easier to bend. 0.8-1.0 mm is only for welding points and decoration and cannot replace the main beams.

Brass Cutting List

Material	Part	Quantity	Single mm	Total mm	Forming	Notes
2.0 mm	Bottom Side Beams	2	120	240	Straight	One each for left and right; first assemble the 120 x 90 mm rectangular frame
2.0 mm	Bottom Front/Rear Crossbeams	2	90	180	Straight	Overlap-welded with side beams; leave 2-3 mm overlap allowance at corners
2.0 mm	Middle Layer Side Rails	2	112	224	Slight outward bend	Located on the outer side of the electronics layer; avoid USB-C and switches
2.0 mm	Middle Layer Front/Rear Crossbeams	2	86	172	Straight	Outer frame protecting the chassis control board and two DRV8833 modules
2.0 mm	Top Side Beams	2	105	210	Straight	Narrowed toward the front; refer to the top cage structure in the diagram
2.0 mm	Top Front/Rear Crossbeams	2	82	164	Straight	Connects the four corner posts at the top
2.0 mm	Four Corner Posts	4	58	232	Straight	Transitions from bottom frame to middle/top layers; tack-weld first, then correct vertical alignment
2.0 mm	Front A-Pillar Diagonal Braces	2	72	144	Slight bend	Extends from the front bumper upward to both sides of the dual-eye plate, forming the front face as shown
2.0 mm	Rear Posts / Speaker Guards	2	58	116	Straight	Provides protection for the rear small speakers and wiring harness
2.0 mm	Front Lower Bumper U-Shaped Bar	1	150	150	U-bend	Bent around a 18-22 mm cylinder; installed below the headlights
2.0 mm	Front Light Bar Crossbeam	1	92	92	Straight	Secures the WS2812B LED strip or ring bracket
2.0 mm	Rear Bumper U-Shaped Bar	1	135	135	U-bend	Protects the rear speakers and charging/programming wiring harness
2.0 mm	Top Handle	1	170	170	U-bend	Bent around a 30-35 mm cylinder; legs welded to the top crossbeam
2.0 mm	Left/Right Wheel Arch Fenders	2	170	340	Large arc bend	Bent around a 34-40 mm cylinder; ensures tires do not rub
1.5 mm	Dual-Eye Protective Rings	2	145	290	Circular ring	Bent around a 42-46 mm cylinder; only protects the outer edge, does not press against the touchscreen
1.5 mm	Protective Ring Connecting Tabs	4	25	100	Short straight	Connects the protective ring to the small front posts; can be fine-tuned later
1.5 mm	Side Diagonal Braces	6	55	330	Diagonal brace	Refer to the X-shaped diagonal braces on the side in the diagram; arranged symmetrically left and right
1.5 mm	Wire Routing / Tying Bridges	6	35	210	Short U-shape	Provides fixing points for motor wires, LED strips, and speaker wires
1.5 mm	Front Light Small Brackets	2	35	70	L-shape	Supports the LED strip from behind; insulate between the light board and brass
1.5 mm	Rear Speaker Protective Strips	4	45	180	Straight	Creates the circular speaker grille effect at the rear as shown in the diagram

When cutting, allow an extra 2-3 mm per piece. Trim to final length after bending and test fitting. For symmetrical parts, cut one piece first as a template, then use it to replicate the other.

Recommended Tools

Electric soldering iron (80 W or higher) or small flame soldering torch.
Brass-specific flux, solder, or silver solder.
Flat-nose pliers, needle-nose pliers, diagonal cutters, small file, sandpaper.
30–50 mm cylinder for bending double-eye grommets, wheel arches, and top handles.
Multimeter, heat-shrink tubing, Kapton tape, cable ties.
Paper templates, tape, square, used to ensure the base frame is not skewed.

Assembly Sequence Overview

Stage	Task	Method	Acceptance
0	Prepare Base Template	Print or trace the `AR-MK1-003_BaseTemplate.svg` onto paper to draw a 110 x 72 mm base plate and a 120 x 90 mm outer frame. Compare all brass parts against the paper template before cutting.	Centerline, wheel axle lines, and battery position marked on the base plate.
1	Drill Base Plate	Cut a 110 x 72 mm FR4/acrylic base plate. Drill M2 brass pillar holes, battery tie-down holes, and four N20 motor mounting holes/slots.	Smooth plate edges; M2 screws should pass through smoothly.
2	Install Power Base Layer	Secure the 18650 battery holder, four N20 motors, four 64T gear wheels, 5 V high-current boost module, and motor branch switch. Do not install the brass cage frame yet.	Wheels do not scrape the base plate; all four wheels touch the table simultaneously; battery can be removed; switch can be toggled from the side.
3	Weld Bottom Brass Rectangle Frame	Weld a 120 x 90 mm bottom frame using 2.0 mm brass rods. Reinforce corners by wrapping 0.8–1.0 mm fine copper wire 2–3 turns before soldering.	Frame sits flat on the table without warping; corners are essentially square.
4	Build Middle Protection Frame	Weld the middle-layer side rails and front/rear crossbeams at approximately Z = 42–48 mm height. This layer protects the bottom control board, front and rear DRV8833 modules, and wiring harness.	Leave at least 3 mm clearance above modules; USB-C port remains unobstructed.
5	Install Electronics Middle Layer	Mount the XIAO ESP32C3 bottom control board, front DRV8833, rear DRV8833, and 5 V high-current boost module onto the middle or base plate. Insert wires first, then tighten screws.	Drive board solder pads do not touch brass; signal wires have slack.
6	Build Front Face and Dual-Eye Bracket	Install the ESP32 Dual-Eye board using M2 brass pillars. Then assemble the front A-pillar, dual-eye protective ring, and front light-bar crossbeam. Weld the protective ring last to avoid pressing on the display.	Dual-Eye board width 93.5 mm may slightly protrude; protective ring does not block the touch area.
7	Build Top and Side Cage Frame	Weld the upper-layer side beams, crossbeams, top handle, and left/right wheel-arch rails. Use 1.5 mm brass rods for diagonal bracing; keep left and right symmetrical.	Overall vehicle height kept at about 110 mm; wheels can rotate freely.
8	Route and Secure Wiring	Route battery and motor wires along the inner side of the base; UART and lighting data lines along the middle layer; speaker wires along the inside of the front or rear. Secure every 30–40 mm using heat-shrink tubing or cable ties.	Wiring does not touch tires; insulation is not abraded by brass edges.
9	Power-Up in Stages	First power only the Dual-Eye main controller; then connect the XIAO bottom control board; next connect the front and rear DRV8833 modules with wheels suspended; finally connect the WS2812B LEDs and speaker.	No overheating, odors, reboots, or abnormal motor jitter observed.

Brass Frame Construction

First, make the bottom rectangular frame (120 × 90 mm). Align four 2.0 mm brass rods on the paper template, overlap the corners by 2–3 mm, and tack-weld.
Place the bottom frame on the bench, press flat, and confirm that all four corners are flush before fully welding the joints.
Weld the vertical corner posts in place with tack welds only. Once the posts are vertical, weld the mid-level side rails.
Recommended mid-level rail height: 42–48 mm. This protects the bottom control board, the front and rear DRV8833 motor drivers, and the wiring harness.
Angle the front A-posts slightly rearward to match the reference drawing’s front face. Ensure the posts do not block the dual-screen display, USB-C port, or touch area.
Install the dual-eye guard ring last. Bend a 1.5 mm brass rod around a 42–46 mm cylinder to form a ring that only shields the outer edge of the screens—it must not press on the glass.
Mount the front light-bar cross-member below the dual eyes and above the bumper. The WS2812B LED strip must have insulating tape applied to its back before it is fastened to the bracket.
Shape the top handle from a 2.0 mm brass rod into a U-shape. Temporarily tie it to the upper crossbeam to check height and proportions before permanently welding.
Form the side fender guards by bending 34–40 mm diameter arcs; leave at least 2 mm clearance around the outer edge of each tire.
Install the diagonal braces last. They serve as decoration and anti-twist reinforcement; do not position them so they block access to the battery bay, USB-C port, or power switch.

Wiring General Principles

First connect the power wires, then the common ground, then the signal wires, and finally the lights and speaker. Any wire running near the brass frame must be covered with heat-shrink tubing or wrapped with Kapton tape. The brass frame is used only for structure and decoration; it must not serve as the negative power rail or ground.

Wiring Operation Sheet

Circuit	From	To	Wire Gauge	Notes
Main battery branch	18650 battery pack BAT+ / BAT-	ESP32 battery port BAT+ / BAT-	MX1.25 2P or factory battery wire	Use a multimeter to confirm polarity first. If making a Y-split, the main control branch still connects to the battery port; do not connect the 5 V boost output to the battery port.
Motor power branch	18650 BAT+	Motor branch switch → 5 V boost IN+	22-24 AWG red wire	This line powers the motors and lights; it is recommended to add an independent switch only on the motor branch.
Common ground	Battery BAT- / boost OUT- / DualEye GND	XIAO GND / front DRV8833 GND / rear DRV8833 GND / WS2812B GND	20-22 AWG black wire or small distribution board	All GND must share a common ground; otherwise UART, motor, and light control signals will be unstable.
Boost to motor driver	5 V boost OUT+ / OUT-	Front DRV8833 VM/GND; rear DRV8833 VM/GND	20-22 AWG red/black main wires, short branches to the two driver boards	The four motors have high startup current; VM only connects to the motor power. Do not power motors from ESP32/DualEye 3.3 V.
DualEye to XIAO UART	DualEye LCD1 Pin10 UART_TXD / Pin9 UART_RXD / GND	XIAO D7(GPIO20) RX / D6(GPIO21) TX / GND	26-28 AWG signal wires + SH1.0 14P adapter cable	TX/RX are crossed; GND must share a common ground. ESP32-S3 UART is 3.3 V TTL; do not connect RS232. If the chassis board TX is 5 V, perform voltage division or level shifting before entering DualEye RX.
XIAO logic power	5 V boost OUT+ / GND or USB-C	XIAO 5V/VIN / GND	24-26 AWG red/black wire	Only use 5 V when the XIAO interface allows it; during debugging, power via USB-C first. Motor VM does not draw power from the DualEye board.
XIAO to front/rear DRV8833 boards	XIAO D2(GPIO4)/D3(GPIO5)/D4(GPIO6)/D5(GPIO7)	AIN1/AIN2/BIN1/BIN2 on both DRV8833 boards wired in parallel	26-28 AWG signal wires, can be fanned out via a small distribution board	D2-D5 drive both front and rear DRV8833 boards; the current firmware still uses left/right differential control rather than four-wheel independent closed-loop.
Front DRV8833 to front motors	AOUT1/AOUT2; BOUT1/BOUT2	Left-front N20; right-front N20	Motor’s own wires or 24-26 AWG	If a wheel spins backward during forward motion, swap the two motor wires.
Rear DRV8833 to rear motors	AOUT1/AOUT2; BOUT1/BOUT2	Left-rear N20; right-rear N20	Motor’s own wires or 24-26 AWG	Rear wheels must turn the same direction as the corresponding front wheels; left-front + left-rear form the left logical side, right-front + right-rear form the right logical side.
WS2812B data conversion	ESP32 free GPIO	AHCT/HCT level shifter A input	26-28 AWG signal wire	Level-shifter VCC = 5 V, GND common; if using 74AHCT1G125, enable OE per module instructions. Short direct connections are only suitable for temporary testing.
WS2812B lights	5 V boost OUT+ / GND; level-shifter Y output	WS2812B 5V / GND / DIN	Power: 24-26 AWG; data: 26-28 AWG	Y output passes through a 330 Ω resistor to DIN; place a 470-1000 µF capacitor across the light board’s 5 V/GND. Limit brightness to 20-40 %.
Buzzer	ESP32 SPK+ / SPK-	4 Ω 3 W or 8 Ω 1-2 W buzzer	Fine, flexible twisted pair	Do not connect either buzzer terminal to GND; connect directly across the speaker interface on the main board.

Recommended Wire Lengths

Wire Type	Recommended Length	Usage
20-22 AWG Red Wire	~1.0-1.2 m	Battery positive terminal, motor branch, boosted power bus to front/rear DRV8833
20-22 AWG Black Wire	~1.0-1.2 m	Common ground bus, motor branch negative, front/rear driver board GND
26-28 AWG Multi-color Signal Wire	~1.5-2.0 m	UART, XIAO to DRV8833, WS2812B data and level conversion
Fine Flexible Twisted Pair	~0.3 m	Small speaker wires, keep away from motor wires
Heat Shrink Tubing	1-5 mm mixed sizes	Insulation for every solder joint, wire passing through brass, and back of LED strips

DualEye UART Interface Pinout

DualEye Interface Pin	Signal	Connection/Usage
LCD1-Board SH1.0 14PIN Pin 10	UART_TXD	Connect to chassis control board RX; DualEye sends AR1 motion/light commands
LCD1-Board SH1.0 14PIN Pin 9	UART_RXD	Connect to chassis control board TX; if chassis board TX is 5 V TTL, use voltage division or level shifting first
LCD1-Board SH1.0 14PIN Pin 2 or Pin 6	GND	Connect to chassis control board GND; must share common ground
LCD1-Board SH1.0 14PIN Pin 5	3V3	Only for 3.3 V logic reference or low-power peripheral power; do not power chassis board/motors

Wiring Suggestions

Run battery and motor power wires along the inner side of the bottom layer, keeping them as short as possible and away from the ESP32 screen ribbon cable.
Twist motor wires in pairs and route them along the left and right sides of the bottom frame, merging them before entering the DRV8833.
Keep the 4 control wires from XIAO D2-D5 to the two DRV8833 boards as short as possible and separate from the motor power wires; each signal wire can be split at a small distribution point to the front/rear driver board.
If using dual-board UART, route the three wires—Pin10 UART_TXD, Pin9 UART_RXD, and GND—from the back of the DualEye down to the chassis board, keeping them away from motor power wires. If the chassis board TX is 5 V, use a level shifter first.
Route the WS2812B data line from the ESP32 reserved GPIO to the AHCT/HCT level shifter, then through a 330 Ω resistor to the DIN of the front LED strip.
Route speaker wires along the inner side of the front or rear of the rover, avoiding motor wires to prevent motor noise from coupling into the audio.
Secure wires every 30–40 mm using 1.5 mm brass cable ties; ensure heat shrink tubing is used between the wire and the brass to prevent damage.

Power-on Sequence

With the battery removed, use a multimeter to check that BAT+ and GND are not short-circuited.
Connect the battery only to the ESP32 main control board and confirm that the dual OLED screens, touch interface, and USB-C port are functioning.
Connect the 5 V boost module unloaded, adjust it to approximately 5.0 V, then power off.
Connect the XIAO chassis board; send AR1,PING or AR1,STOP via the USB-C serial port to confirm that the chassis firmware is online.
Connect the front and rear DRV8833 control and power wires, but keep the wheels off the ground. Use a low PWM signal to test the front and rear wheels on the left side first, then the right side.
If a motor spins in the wrong direction, simply swap the AOUT or BOUT wires for that motor.
Connect the AHCT/HCT level shifter and WS2812B LEDs, limiting brightness to 20–40 %. Test the red, green, and blue colors first.
Connect the small speaker, starting with low volume. Connect the speaker wires to SPK+ and SPK–; do not connect them to GND.
Finally, perform a ground test: drive straight for 30 cm, then test in-place turns, and finally test low-speed cruising.

Common Mistakes to Avoid

Inserting M3 brass standoffs into M2 holes: Do not do this; use M2 screws exclusively to secure the main control board.
Using PCA9685 as a motor driver: It is not a motor driver; if used, it is only an optional PWM expansion board for the chassis, while the DRV8833 is responsible for supplying current to the motors.
Connecting WS2812B data line to PCA9685: This will not work; WS2812B requires a single-line data GPIO from the ESP32.
Powering 5 V WS2812B directly from ESP32 3.3 V data line long-term: Short wires may work, but for the official version, it is recommended to add an AHCT/HCT level shifter.
Connecting the 5 V boost output to the main control board's battery port: Do not do this.
Not sharing a common ground between dual UART boards: Do not do this; lack of common ground will cause serial port errors.
Back-feeding 5 V or motor VM from the chassis board to DualEye: Do not do this; DualEye should only be connected to its own battery/USB/allowed logic interfaces.
Connecting one end of the small speaker to GND: Do not do this; connect according to SPK+ / SPK-.
Not cleaning flux residue after soldering brass: Residue can corrode copper parts and may contaminate electronic boards.

Files by @davidwang960707-gpu, at commit 675d6f2, read from GitHub in your browser. Hardware license: MIT; software license: MIT. Robotheca doesn't review code: read it before running it.