# How to build the SunFounder GalaxyRVR, step by step The GalaxyRVR is a six wheel Mars rover kit you drive from your phone. This guide breaks the build into 49 small steps, each with its own drawing, the exact screws to use and the mistake most people make on that step. Updated 2026-10-27. HTML version with a drawing for every step: https://robotsforthat.com/robot-kits/galaxyrvr-build-guide/ Free step by step build tool with an AI photo coach: https://robotsforthat.com/lab/build/mars-rover/steps/ ## Short answer Plan for 3 to 4 hours. Build the body and legs first, then the board and battery, motors and wheels, sensors, camera and solar roof. No soldering and no coding. A parent and a kid can do it together in one afternoon. ## Facts - Kit: SunFounder GalaxyRVR Mars Rover Kit - Price: $129.99 at SunFounder - Build time: 3 to 4 hours - Steps: 49 - Difficulty: Beginner, patient - Coding needed: None - Age: Maker says 15+. Younger kids build it great with a parent. ## What is in the box - Brain: Arduino UNO R3 board. Runs the rover. Its program comes already loaded. - Eyes: ESP32 camera on a tilting mast. Streams live video to your phone. - Legs: 6 motors with rocker bogie suspension. The same idea NASA uses so rovers climb over bumps. - Senses: Ultrasonic sensor and 2 infrared sensors. Let it see walls and steer around them by itself. - Power: Rechargeable battery and a solar panel. About 90 minutes of driving per charge. - You add: A phone and a USB-C phone charger. Any 5V 2A charger works for charging. ## Part 1: Get ready (2 steps, about 15 minutes) ### Step 1: Clear a table and sort the parts Open the box on a big table. Sort the screws, nuts and plates into small piles so each one is easy to find. Tip: A muffin tin or a few small bowls make the screw piles easy. Check: Screws and nuts are in separate piles. Common mistake: Pouring every bag out together. Keep screws in their bags until you sort them by size. ### Step 2: Check nothing is missing Check every bag, plate and board is there. Screws come with a few spares, so do not worry about a missing one. Check: Every bag, plate and board is there. Common mistake: Counting screws one by one. Bags have spares, so only check plates, boards and motors. ## Part 2: Body and legs (9 steps, about 45 minutes) ### Step 3: Join plates A and B Screw the two blue brackets onto plate A and plate B with four M3x6 screws. Parts: Plate A, Plate B, M3x6 screws Check: Plates A and B form the box shaped body. Common mistake: Grabbing M3x10 screws. This step uses the short M3x6 ones. ### Step 4: Build the first leg joint Fix plate D to a leg with an M3x10 screw, a metal washer and a self-locking nut. Parts: Plate D, M3x10 screw, Metal washer, Self-locking nut, Cross wrench Tip: Use self-locking nuts and metal washers here. Plain M3 nuts and spring washers are for the motors later. Check: Plate D is attached to the leg. Common mistake: Using a plain nut. Leg joints need the self-locking nut and the metal washer. ### Step 5: Add plate C Fix plate C to the other leg the same way: M3x10 screw, metal washer, self-locking nut. Parts: Plate C, M3x10 screw, Metal washer, Self-locking nut Check: Both legs have their small plate. Common mistake: Mounting plate C facing the wrong way. It should mirror plate D on the first leg. ### Step 6: Attach the legs to one side Fix the leg to the side of the body with an M3x25 screw, a metal washer and a self-locking nut. Parts: M3x25 screw, Metal washer, Self-locking nut Tip: Check the small arrows printed on the parts all point the same way, toward the front. Check: The leg hangs from one side of the body. Common mistake: Mixing up M3x25 and M3x14 screws. Lay one next to the drawing to check the length. ### Step 7: Attach the legs to the other side Repeat on the other side with an M3x25 screw, metal washer and self-locking nut. Parts: M3x25 screw, Metal washer, Self-locking nut Check: Legs hang from both sides. Common mistake: Building the second side the same as the first. It is a mirror copy, not a copy. ### Step 8: Fit plate E Fix plate E on top with an M3x10 screw, metal washer and self-locking nut. Parts: Plate E, M3x10 screw, Metal washer, Self-locking nut Check: Plate E sits across the top. Common mistake: Overtightening the nut. The joint has to move later, so stop when it is snug. ### Step 9: Link the top bar Connect the top bar to the leg with an M3x10 screw, metal washer and self-locking nut. Parts: M3x10 screw, Metal washer, Self-locking nut Check: The top bar links both sides. Common mistake: Linking the bar to the wrong hole. Use the end hole of the leg, like the drawing. ### Step 10: Fit the plate F joints On both sides, join plate F with an M3x14 screw, two acrylic washers and a self-locking nut. Parts: Plate F, M3x14 screws, Acrylic washers, Self-locking nuts Check: Both plate F joints are on. Common mistake: Forgetting the acrylic washers. Without them the joint rubs and squeaks. ### Step 11: Check: the legs swing freely Tighten the self-locking nut fully with the cross wrench, then loosen it a little so the plate can swing. Do this on every joint from the last 7 screens. Tip: This is what lets your rover climb bumps like NASA rovers. Stiff joints mean it gets stuck. Check: Each leg swings by itself when you lift the body. Nothing wobbles loose. Common mistake: Leaving joints tight. A stiff leg makes the rover tip over on bumps. ## Part 3: Brain and battery (5 steps, about 20 minutes) ### Step 12: Add the Velcro stickers Stick one Velcro sticker on the battery and the matching one inside the body. Parts: Velcro sticker, Battery Check: Both stickers are on. Common mistake: Putting the Velcro too close to the edge. Keep it centered so the battery sits flat. ### Step 13: Mount the battery Press the battery onto the Velcro inside the body, with its wire free so it reaches the board above. Parts: Battery Check: The battery sits firm and the wire reaches up. Common mistake: Burying the battery wire under the battery. Leave it free so it reaches the board. ### Step 14: Mount the R3 board Screw four M3x8+6 standoffs onto the top plate, then fix the R3 board on them with four M3x6 screws. Parts: R3 board, M3x8+6 standoffs, M3x6 screws Check: The board sits flat on four posts. Common mistake: Screwing the standoffs in crooked. Turn them by hand first, then finish with the tool. ### Step 15: Press the shield on top Line up all the pins of the GalaxyRVR shield with the R3 board and press it straight down. Parts: GalaxyRVR shield Tip: Look along the side before pressing. A pin outside its hole bends and stops the rover working. Check: No pins are showing outside the black sockets. Common mistake: Pressing the shield at an angle. One bent pin can stop the whole rover. ### Step 16: Plug in the battery Plug the battery wire into the port marked BATTERY on the shield. Check: The plug clicks in at BATTERY. Common mistake: Plugging the battery into a motor port. It goes only into BATTERY. ## Part 4: Motors and wheels (6 steps, about 40 minutes) ### Step 17: Fit the six motors Fix each motor to its leg with two M3x25 screws, a spring washer and an M3 nut. Do all six. Parts: 6 motors, M3x25 screws, Spring washers, M3 nuts Tip: Motors use plain M3 nuts and spring washers, not self-locking nuts and metal washers. Check: All six motors are fixed and do not wiggle. Common mistake: Using self-locking nuts on the motors. Motors take plain M3 nuts and spring washers. ### Step 18: Plug in the left motors Plug the three left side motor wires into the left ports A, B and C, routing the wires along the top bar. Tip: Front motor to A, middle to B, back to C. If a wheel spins the wrong way later, swap its plug. Check: Three plugs in LEFT. Common mistake: Leaving plugs half in. Push until the plug sits flat in the port. ### Step 19: Plug in the right motors Plug the right side motor wires into the RIGHT ports in the order D, E, F. Check: Three plugs in RIGHT. Common mistake: Using the left ports twice. Right motors go only in D, E and F. ### Step 20: Tie the motor wires Use the cable ties to hold the motor wires against the frame, away from the wheels. Tip: Loose wires get caught in the wheels and snap. Reviewers hit exactly this. Check: No wire can touch a wheel. Common mistake: Pulling ties so tight they pinch the wire. Snug is enough. ### Step 21: Put on the wheels Push a shaft adapter onto each motor, then fix the wheel with an M2.3x20 screw. Do all six. Parts: 6 wheels, Shaft adapters, M2.3x20 screws Check: Six wheels on. Each spins by hand. Common mistake: Skipping the shaft adapter. The wheel will wobble and fall off. ### Step 22: Fit the front posts Screw two M3x28 standoffs onto the front of the body with M3x6 screws. Parts: M3x28 standoffs, M3x6 screws Check: Two tall posts stand at the front. Common mistake: Using the shorter standoffs. These are the tall M3x28 ones. ## Part 5: Sensors and lights (7 steps, about 30 minutes) ### Step 23: Mount the two IR sensors Fix the two IR obstacle sensors on M3x8+6 standoffs at the front with M3x6 screws. Parts: IR obstacle avoidance modules, M3x8+6 standoffs, M3x6 screws Check: One sensor on each front corner. Common mistake: Mounting a sensor upside down. Both LEDs should face forward. ### Step 24: Wire the IR sensors Connect each sensor to the shield with a 3-pin wire: left sensor to IR LEFT, right sensor to IR RIGHT. Tip: Match the pin labels: OUT, + and GND on the sensor to the same labels on the cable. Check: Both sensors are wired. Common mistake: Swapping left and right. The left sensor goes to IR LEFT. ### Step 25: Plug a wire into the ultrasonic sensor Plug the 4-pin wire into the back of the ultrasonic module (the one with two round eyes). Check: The wire is in. Common mistake: Forcing the plug. It only fits one way, so flip it if it resists. ### Step 26: Mount the ultrasonic sensor Fix it to plate G with two R3080 rivets: push the rivet in, then press its pin to lock. Plug the wire into SONAR. Parts: Ultrasonic module, Plate G, R3080 rivets Check: The two eyes look forward. Wire plugged into SONAR. Common mistake: Not pressing the rivet pin. Push the rivet in, then press its pin until it locks. ### Step 27: Peel the light strips Peel the backing off the sticky side of both RGB light strips. Check: Both strips are sticky side up. Common mistake: Touching the sticky side. Fingerprints stop it from sticking well. ### Step 28: Stick on the lights Stick one strip on each side inside the body and plug both into the RGB LED ports. Check: Two strips on. Both plugged into RGB LED. Common mistake: Sticking the strips before checking the cable reaches the port. Hold it in place first. ### Step 29: Fit plate H Screw plate H (the camera bracket) to the top front with two M3x6 screws, its two arms standing up. Parts: Plate H, M3x6 screws Check: Plate H stands up at the front. Common mistake: Mounting plate H backwards. Its two arms stand up at the front. ## Part 6: Camera (10 steps, about 35 minutes) ### Step 30: Charge and switch on the battery Plug the USB-C cable into the shield to charge, then slide the power switch to ON. You need power for the next step. Tip: The servo setup needs power. The rover's preloaded program does the work. Check: A red charge light is on. The green power light is on. Common mistake: Skipping this step. The servo needs power to center itself next. ### Step 31: Plug the servo into pin 6 Plug the small servo motor's wire onto pin 6: brown to GND, red to 5V, orange to 6. It turns to its center by itself. Tip: This puts the servo at exactly 90 degrees, so the camera points straight once mounted. Check: The servo twitches and stops. Common mistake: Plugging the servo in backwards. Brown goes to GND. ### Step 32: Fit the servo arm, then power off Push the servo arm on pointing straight along the servo body, then fix it with the smallest screw from the servo pack. Then slide the power switch to OFF. Check: The arm is fixed. The power light is off. Common mistake: Turning the servo by hand after it centered. Push the arm straight on without twisting. ### Step 33: Put the servo in plate I Fix the servo into plate I with two R2056 rivets. Parts: Servo, Plate I, R2056 rivets Check: The servo sits inside plate I. Common mistake: Putting the servo in with its gear on the wrong side. Match the drawing. ### Step 34: Mount the camera tilt Attach plate I to plate H with M1.5x3 screws on the servo arm and an R3065 rivet on the other side. Parts: M1.5x3 screws, R3065 rivet Check: The camera mount tilts up and down. Common mistake: Using big screws on the servo arm. These are the tiny M1.5x3 screws. ### Step 35: Wire the camera adapter Plug the 5-pin wire into the camera adapter board and the other end into CAMERA on the shield. Check: Wire plugged into CAMERA. Common mistake: Plugging the camera wire into a sensor port. It goes into CAMERA. ### Step 36: Mount the camera adapter Fix the adapter board to the mount with three R3055 rivets. Parts: Camera adapter board, R3055 rivets Check: The adapter sits on the mount. Common mistake: Snapping the adapter on loose. All three rivets must lock. ### Step 37: Connect the camera lens On the ESP32 CAM: lift the little latch, slide the camera ribbon in, close the latch, then stick the camera down. Tip: The ribbon is fragile. Lift the latch gently with a fingernail. Check: The ribbon is held by the closed latch. Common mistake: Pulling the latch too hard. It is tiny and snaps easily. Lift it with a fingernail. ### Step 38: Plug in the ESP32 CAM Push the ESP32 CAM into the adapter, lined up exactly like the drawing. Check every pin is in a socket. Tip: SunFounder warns about this one: backwards means no video later. Check: Camera board lines up with the adapter. Antenna on the ticked side. Common mistake: Putting the ESP32 CAM in backwards. It is the top reason for no video. ### Step 39: Close the bottom Fix the acrylic plate under the body with M3x6 screws and snap its edges in. Parts: Acrylic plate, M3x6 screws Check: The bottom is closed. Common mistake: Trapping a wire under the bottom plate. Check all wires are inside before you close it. ## Part 7: Solar roof (4 steps, about 20 minutes) ### Step 40: Add the roof posts Screw four M3x30+6 standoffs onto the corners of the shield. Parts: M3x30+6 standoffs Check: Four tall posts on the board. Common mistake: Mixing up standoff sizes. These are the tallest ones, M3x30+6. ### Step 41: Add plates J and K Fix plates J and K across the posts with M3x6 screws. Parts: Plate J, Plate K, M3x6 screws Check: Two bars across the posts. Common mistake: Fitting J and K before the posts are tight. Tighten the posts first. ### Step 42: Stick the solar panel on plate L Use the foam tape to stick plate L under the solar panel, wire through the middle. Parts: Solar panel, Plate L, Foam tape Check: Plate L is stuck under the panel. Common mistake: Covering the hole with tape. The solar wire has to pass through the middle. ### Step 43: Mount the roof Snap the roof onto the bars, fix it with an M3x6 screw, tape the wire down with fiber tape and plug it into SOLAR. Check: The roof is on. Wire plugged into SOLAR. Common mistake: Leaving the solar wire loose. Tape it down so it never touches a wheel. ## Part 8: Drive it (6 steps, about 15 minutes) ### Step 44: Charge it fully Plug in the USB-C cable (a 5V 2A phone charger works). A full charge takes about 2 hours. Check: A red charge light is on. The orange battery lights blink. Common mistake: Using a fast laptop charger. A plain 5V 2A phone charger is safest. ### Step 45: Switch it on Unplug the charger. Slide the power switch to ON, slide the mode switch to the left, and press Reset once. Tip: For driving, the mode switch always stays on the left. Right is only for uploading code. Check: Green power light on. The light strips flash green. Common mistake: Mode switch on the right. Right is only for uploading code, left is for driving. ### Step 46: Get the app On your phone, install RoboPilot from the App Store or Google Play. Older kits use SunFounder Controller, which works the same way. Check: The app is installed. ### Step 47: Join the rover's Wi-Fi In your Wi-Fi settings join GalaxyRVR. The password is 12345678. When it says No internet, tap Stay connected. Check: Connected to GalaxyRVR. Common mistake: Switching back to home Wi-Fi when the phone says No internet. Tap Stay connected. ### Step 48: Drive! Open the app and tap Go into. The camera view fills the screen. Push the joystick gently. Tip: Small pushes mean slow. Start slow until you know how it turns. Check: Live camera view. It drives when you push the joystick. Common mistake: Pushing the joystick all the way. Start with small pushes. ### Step 49: Let it drive itself In the app pick Avoid mode, put it on the floor and watch it steer around walls. Then try Follow. Tip: Bumps into walls? Put a box 20 cm in front of each IR sensor and turn its small screw until its light comes on. Check: It turns before hitting a wall. Common mistake: Testing Avoid mode on a dark rug. The IR sensors work best on light, flat floors. ## Troubleshooting ### No camera picture in the app Why: The ESP32 CAM is in its adapter the wrong way, its ribbon is loose, or the camera is not getting power. 1. Turn the rover off. Pull the ESP32 CAM straight out and check it faces the same way as the drawing in step 38. 2. Open the little latch on the ESP32 CAM, push the camera ribbon fully in and close the latch (step 37). 3. Check the 5 pin wire is fully in at CAMERA on the board (step 35). 4. Turn on, press Reset and reconnect the app. Comes from step 38. ### The GalaxyRVR Wi-Fi does not show up Why: The rover is in upload mode, the battery is flat, or the camera board is not powered. The camera board makes the Wi-Fi. 1. Check the battery lights. If both are off, charge it. 2. Slide the mode switch to the left (Run), not Upload. 3. Press Reset on the board and wait 20 seconds. 4. Check the ESP32 CAM is fully pushed into its adapter. If its small light stays off, it has no power. Comes from step 45. ### The app keeps disconnecting Why: Your phone leaves the rover's Wi-Fi because it has no internet, or another network on the same channel interferes. 1. When your phone says No internet, tap Stay connected. 2. Turn off Wi-Fi assist on iPhone or smart network switch on Android. 3. Change the rover's Wi-Fi channel: join GalaxyRVR, open 192.168.4.1 in a browser, pick a new channel on the AP page (try 3, then 5), then tap Reboot on the Base page. Comes from step 47. ### The app sees the Wi-Fi but will not connect Why: Custom code uploaded to the board replaced the rover's own program, or the camera board firmware is old. 1. Slide the mode switch to the left (Run) and press Reset. 2. If you uploaded your own Arduino code, reinstall the official GalaxyRVR firmware with SunFounder's web flasher. 3. Update the ESP32 CAM firmware from SunFounder's docs. Comes from step 46. ### A wheel spins the wrong way Why: Two motor plugs are swapped. 1. Left motors go in A, B and C. Right motors go in D, E and F. 2. Swap the plug of the wrong wheel with its neighbour and test again. Comes from step 18. ### One wheel does not turn Why: Its plug is not fully in, or its wire got caught and snapped. 1. Push that motor's plug fully into its port. 2. Follow the wire from motor to board. Look for a cut or pinch near the wheel. 3. Tie loose wires to the frame so the wheels cannot catch them (step 20). Comes from step 20. ### No lights when charging or switching on Why: The battery plug is loose or the battery is flat. 1. Check the battery plug is fully in at BATTERY (step 16). 2. Charge for 2 hours with a 5V 2A phone charger. 3. If the power switch feels loose and the lights flicker when you touch it, contact SunFounder support. Comes from step 16. ### The battery runs out very fast Why: The battery was not fully charged, or a loose power connection keeps cutting in and out. 1. Charge fully for about 2 hours before driving. 2. Check the battery plug and the shield are firmly seated. 3. About 90 minutes of driving per charge is normal. Comes from step 44. ### It bumps into walls in Avoid mode Why: The infrared sensors are not tuned for your room. 1. Put a box 20 cm in front of one IR sensor. 2. Turn the sensor's small screw until its light just comes on. 3. Repeat for the other sensor. Light, flat floors work best. Comes from step 49. ### The camera points up, down or sideways Why: The servo arm went on before the servo centered itself. 1. Undo the tiny screw and pull the servo arm off. 2. Power on with the servo plugged into pin 6 so it centers (step 31). 3. Push the arm back on pointing straight and fix it again (step 32). Comes from step 32. ### The rover tips over or gets stuck on bumps Why: The leg joints are too tight to swing. 1. Loosen each leg joint nut a quarter turn with the cross wrench. 2. The legs should swing freely when you lift the body (step 11). Comes from step 11. ### A part is missing from the box Why: Rare, but it happens. 1. Check the spare bags first. Screws come with extras. 2. Email service@sunfounder.com with a photo of your parts. They send replacements. Comes from step 2. ## Sources - [SunFounder GalaxyRVR quick start](https://docs.sunfounder.com/projects/galaxy-rvr/en/latest/quick_start/quick_start_robopilot.html) - [GalaxyRVR board: switches and lights](https://docs.sunfounder.com/projects/galaxy-rvr/en/latest/hardware/cpn_galaxy_shield.html) - [SunFounder GalaxyRVR paper guide (PDF)](https://github.com/sunfounder/sf-pdf/raw/master/assembly_file/z0112v11-a0001012-galaxyrvr.pdf) - [SunFounder GalaxyRVR FAQ](https://docs.sunfounder.com/projects/galaxy-rvr/en/latest/faq.html) SunFounder GalaxyRVR is a trademark of SunFounder. robotsforthat is not affiliated with SunFounder.