# NXP Cup Car - Complete Assembly Guide [← Back to Main](../tutorial.md) | [← Shield Assembly](shield-assembly.md) ## Assembly Steps Overview 1. [Chassis Preparation](#step-1-chassis-preparation) 2. [Mounting Motors](#step-2-mounting-motors-on-chassis) 3. [Installing HEX Adapters](#step-3-installing-hex-adapters) 4. [Mounting Wheels](#step-4-mounting-wheels) 5. [Installing Ball Caster](#step-5-installing-ball-caster) 6. [Mounting Spacers](#step-6-mounting-spacers-for-frdm-mcxn947) 7. [Mounting FRDM Board](#step-7-mounting-frdm-mcxn947-board) 8. [Connecting Shield](#step-8-connecting-nxpcup-shield) 9. [Connecting Motors](#step-9-connecting-motors-to-shield) 10. [Mounting Line Sensors](#step-10-mounting-line-sensors) 11. [Connecting Ribbon Cable](#step-11-connecting-ribbon-cable) 12. [Installing Battery](#step-12-installing-battery) 13. [Connecting Battery](#step-13-connecting-battery-to-shield) 14. [Final Checks](#step-14-final-checks-before-power-on) 15. [First Power-On Test](#step-15-first-power-on-test) --- ## Before You Begin ### Required Components - [ ] Assembled NXPCUP-Shield (from [Shield Assembly Guide](shield-assembly.md)) - [ ] FRDM-MCXN947 development board - [ ] 3D printed chassis or base plate - [ ] 2x DC motors (25GA-370) - [ ] 2x Wheels (65mm) - [ ] 2x HEX adapters - [ ] 1x Ball caster - [ ] Line sensor array - [ ] Ribbon cable - [ ] 16x M3 screws (6mm length) - [ ] 2x M3 x 10mm spacers - [ ] 4x M3 x 20mm spacers - [ ] LiPo battery 7.4V 2200mAh with XT60 connector ### Required Tools - [ ] Phillips screwdriver (for M3 screws) - [ ] Pliers - [ ] Multimeter - [ ] Cable ties/zip ties ### Safety Precautions - ⚠️ **Battery Safety:** - Never connect battery with reversed polarity - Never short circuit battery terminals - Keep battery away from metal objects - Charge only with appropriate LiPo charger - Never leave charging battery unattended - **Mechanical Safety:** - Ensure all screws are tight before operation - Keep fingers away from moving parts - Wear safety glasses when cutting or drilling --- ## Step 1: Chassis Preparation ### Instructions 1. **Inspect the chassis:** - Check for any defects or rough edges - If 3D printed, remove any support material - Sand rough edges if necessary 2. **Identify mounting points:** - Motor mounting holes (usually 4 holes per motor) - Ball caster mounting holes (usually 2 holes) - Board mounting holes (usually 4 holes) - Sensor mounting holes (usually 2-4 holes) 3. **Clean the chassis:** - Remove any dust or debris - Ensure mounting surfaces are flat 4. **Organize hardware:** - Separate screws by type - Have spacers ready - Keep small parts in containers ### Quality Check - [ ] Chassis is clean and free of defects - [ ] All mounting holes are clear and accessible - [ ] Mounting surfaces are flat - [ ] All hardware is organized and ready --- ## Step 2: Mounting Motors on Chassis ### Instructions 1. **Identify motor positions:** - Left motor position - Right motor position - Motors should be parallel to each other 2. **Position the first motor (left):** - Align motor mounting holes with chassis holes - Motor shaft should point outward (toward wheel position) - Motor body should be inside the chassis 3. **Insert screws:** - Use 2x M3 x 6mm screws per motor - Insert screws from the external side of chassis - Do not fully tighten yet 4. **Align the motor:** - Ensure motor is perpendicular to chassis - Motor shaft should be parallel to ground - Adjust position if needed 5. **Tighten screws:** - Tighten in a cross pattern (opposite corners) - Tighten evenly to avoid misalignment - Ensure motor is firmly mounted 6. **Repeat for second motor (right):** - Same procedure as left motor - Ensure both motors are aligned parallel 7. **Verify motor alignment:** - Both motor shafts should be at same height - Both shafts should be parallel - Rotate shafts by hand - should turn freely ### Quality Check - [ ] Both motors are securely mounted (8 screws total) - [ ] Motors are parallel to each other - [ ] Motor shafts are at same height - [ ] Motor shafts rotate freely without binding - [ ] All screws are tight - [ ] Motors do not wobble **Note:** Proper motor alignment is critical for straight driving! --- ## Step 3: Installing HEX Adapters ### Instructions 1. **Prepare HEX adapters:** - Take the 2 HEX adapters - Identify the set screw on each adapter - Loosen the set screw (do not remove completely) 2. **Check motor shaft:** - Most motors have a flat side on the shaft (D-shaft) - This flat side prevents the adapter from slipping - Clean the shaft if needed 3. **Install first adapter (left motor):** - Slide the HEX adapter onto the motor shaft - Push it on as far as it will go - Align the set screw with the flat side of the shaft 4. **Tighten the set screw:** - Tighten firmly but do not over-tighten - The adapter should not slip on the shaft 5. **Test the connection:** - Try to rotate the adapter by hand - It should not slip on the motor shaft - The motor shaft should rotate with the adapter 6. **Repeat for second adapter (right motor):** - Same procedure 7. **Verify both adapters:** - Both should be pushed fully onto shafts - Both should be tight and not slip - Both should be at same distance from motor body ### Quality Check - [ ] Both HEX adapters are installed - [ ] Adapters are pushed fully onto motor shafts - [ ] Set screws are aligned with flat side of shaft - [ ] Set screws are tight - [ ] Adapters do not slip when rotated by hand - [ ] Both adapters are at same position on shafts **⚠️ IMPORTANT:** If adapters slip during operation, the wheels will not turn properly! --- ## Step 4: Mounting Wheels ### Instructions 1. **Prepare wheels:** - Take the 2 wheels (65mm diameter) - Check that the hexagonal hole is clean - Remove any manufacturing debris 2. **Install first wheel (left):** - Align the hexagonal hole in the wheel with the HEX adapter - Push the wheel onto the adapter - The wheel should slide on smoothly - Push until the wheel is fully seated 3. **Secure the wheel:** - Most wheels have a set screw or retaining screw - Insert and tighten the screw - Ensure the wheel is firmly attached 4. **Test the wheel:** - Rotate the wheel by hand - It should turn the motor shaft - No wobbling or play 5. **Repeat for second wheel (right):** - Same procedure 6. **Check wheel alignment:** - Both wheels should be parallel - Both wheels should be at same height - Spin each wheel - should rotate freely - No rubbing against chassis ### Quality Check - [ ] Both wheels are installed - [ ] Wheels are fully seated on HEX adapters - [ ] Retaining screws are tight - [ ] Wheels are parallel to each other - [ ] Wheels rotate freely without wobbling - [ ] Wheels do not rub against chassis - [ ] Both wheels are at same height from ground **Note:** Wheel alignment affects driving performance. Ensure they are parallel! --- ## Step 5: Installing Ball Caster ### Instructions 1. **Identify ball caster position:** - Mounted at front of chassis - Should be centered left-to-right - Position determines weight distribution 2. **Position the ball caster:** - Place ball caster on mounting surface - Align mounting holes with chassis holes - Ball should face downward 3. **Check height:** - With wheels on ground, chassis should be level - Ball caster should just touch the ground - Adjust if chassis has multiple mounting positions 4. **Insert screws:** - Use 2 x M3 x 6mm screws - Insert from bottom of chassis 5. **Tighten screws:** - Tighten evenly - Ensure ball caster is firmly mounted 6. **Test the ball caster:** - Ball should rotate freely in all directions - No binding or sticking - Should roll smoothly ### Quality Check - [ ] Ball caster is mounted securely (2 screws) - [ ] Ball caster is centered on chassis - [ ] Ball rotates freely in all directions - [ ] Chassis is level when on wheels and ball caster - [ ] All screws are tight **Note:** The ball caster provides the third point of support. Proper height is important for stability. --- ## Step 6: Mounting Spacers for FRDM-MCXN947 ### Instructions 1. **Identify board mounting positions:** - Chassis have 4 mounting holes for the development board - These holes match the FRDM-MCXN947 mounting holes 2. **Determine spacer configuration:** - **All positions:** 4 x M3 x 20mm spacers - This provides proper height for the FRDM board mounting 3. **Install spacers (20mm):** - Take 4x M3 x 20mm spacers - Position at all 4 mounting holes - Insert M3 x 6mm screw from bottom of chassis - Screw into the spacer from below - Tighten securely 5. **Verify spacer installation:** - All 4 spacers should be perpendicular to chassis - Spacers should be firmly attached - No wobbling ### Quality Check - [ ] 2x M3 x 20mm spacers installed at rear positions - [ ] 2x M3 x 10mm spacers installed at front positions - [ ] All spacers are perpendicular to chassis - [ ] All spacers are tight (4 screws from bottom) - [ ] Spacers do not wobble **Note:** The different spacer heights create a slight tilt, which can help with sensor positioning. --- ## Step 7: Mounting Spacers for Line Sensors ### Instructions 1. **Identify sensor spacer mounting positions:** - Chassis have 2 mounting holes for line sensor spacers - These holes are at the front of the chassis - Position should allow sensors to be centered and face downward 2. **Determine spacer configuration:** - **Standard configuration:** 2x M3 x 10mm spacers - Spacers create proper height for sensor positioning - Sensors should be 3-5mm from ground when mounted 3. **Install sensor spacers:** - Take 2x M3 x 10mm spacers - Position at sensor mounting holes on chassis - Insert M3 x 6mm screw from bottom of chassis - Screw into the spacer from below - Tighten securely 4. **Verify spacer installation:** - All spacers should be perpendicular to chassis - Spacers should be at same height - Spacers should be firmly attached - No wobbling 5. **Check sensor mounting alignment:** - Place line sensor array on spacers (without screwing) - Verify sensor height from ground (3-5mm optimal) - Ensure sensors will be parallel to ground - Adjust spacer length if needed ### Quality Check - [ ] All sensor spacers installed (typically 2x M3 x 10mm) - [ ] All spacers are perpendicular to chassis - [ ] All spacers are at same height - [ ] All spacers are tight (screws from bottom) - [ ] Spacers do not wobble - [ ] Sensor height will be 3-5mm from ground when mounted **Note:** Proper sensor height is critical for line detection. The 3-5mm distance provides optimal detection while preventing scraping on uneven surfaces. --- ## Step 8: Installing Battery ### Instructions 1. **Identify battery mounting location:** - Battery mounts in center of chassis - Dedicated battery holder/support is provided - Should be accessible for removal/replacement 2. **Prepare battery mounting:** - Locate the dedicated battery support in center of chassis - Prepare zip ties for securing battery - Ensure battery support is clean and free of debris 3. **Position the battery:** - Place battery in the dedicated center support - XT60 connector should be accessible - Battery should be centered for weight distribution - Ensure battery is oriented correctly (check polarity markings) 4. **Secure the battery:** - Thread zip tie(s) through battery support slots - Wrap zip tie around battery - Pull zip tie tight to secure battery firmly - Trim excess zip tie length 5. **Verify battery installation:** - Battery should be firmly mounted in center support - Should not move when chassis is shaken - XT60 connector is accessible - Battery does not interfere with wheels or other components - Zip tie is tight and secure ### Quality Check - [ ] Battery is mounted in center dedicated support - [ ] Battery is firmly secured with zip tie (shake test) - [ ] XT60 connector is accessible - [ ] Battery is centered for weight distribution - [ ] Battery does not interfere with wheels or components - [ ] Battery polarity markings are visible - [ ] Zip tie is tight and trimmed **⚠️ SAFETY:** Ensure battery is very secure. A loose battery can cause damage or fire hazard! --- ## Step 9: Mounting FRDM-MCXN947 Board ### Instructions 1. **Prepare the FRDM-MCXN947 board:** - Remove from anti-static packaging - Inspect for any damage - Identify the 4 mounting holes 2. **Position the board:** - Align the board mounting holes with the spacers - USB connector should be accessible (usually toward rear or side) - Ensure correct orientation 3. **Place board on spacers:** - Carefully lower the board onto the spacers - All 4 mounting holes should align - Do not force - if holes don't align, check spacer positions 4. **Secure the board:** - Insert 4x M3 x 6mm screws through board holes - Screw into the top of each spacer - Tighten in a cross pattern (opposite corners) - Do not over-tighten (can crack the PCB) 5. **Verify board installation:** - Board should be stable and level (or at designed angle) - No wobbling - USB connector is accessible - All mounting screws are snug ### Quality Check - [ ] FRDM-MCXN947 board is mounted on spacers - [ ] All 4 mounting screws are installed and tight - [ ] Board is stable with no wobbling - [ ] USB connector is accessible - [ ] Board is at correct orientation - [ ] No stress on the PCB **⚠️ CAUTION:** Do not over-tighten screws - this can crack the PCB! --- ## Step 10: Connecting NXPCUP Shield ### Instructions 1. **Prepare the shield:** - Take the assembled NXPCUP-Shield - Inspect all header connectors - Ensure no bent pins 2. **Identify mating connectors:** - Shield has female headers (J1, J2, J5, J6) - FRDM-MCXN947 has corresponding male headers - Check alignment before connecting 3. **Align the shield:** - Hold shield above the FRDM board - Align all header connectors - Ensure correct orientation (usually marked on PCB) 4. **Connect the shield:** - Lower the shield carefully - All header pins should start entering the sockets - **Do not force!** If pins don't align, lift and realign 5. **Press shield down:** - Apply even pressure across the shield - Press down until shield is fully seated - All connectors should be fully mated 6. **Verify connection:** - Shield should be parallel to FRDM board - No gaps between shield and board headers - No bent pins visible ### Quality Check - [ ] Shield is properly aligned with FRDM board - [ ] All header connectors are fully mated - [ ] No bent pins - [ ] Shield is parallel to FRDM board - [ ] Shield is stable and does not wobble - [ ] All connectors (J1, J2, J5, J6) are connected **⚠️ IMPORTANT:** Bent pins can cause malfunction or damage. Be very careful during this step! --- ## Step 11: Mounting Line Sensors ### Instructions 1. **Identify sensor mounting position:** - Sensors mount at front of chassis (or rear, depending on design) - Should be centered left-to-right - Should face downward toward the track 2. **Prepare the sensor array:** - Line sensor array typically has multiple IR sensors - Check that all sensors are clean - Identify mounting holes on sensor PCB 3. **Position the sensors:** - Place sensor array on the spacers installed in Step 7 - Sensors should point downward - Align mounting holes with spacer tops - Ensure sensors are perpendicular to driving direction 4. **Secure the sensors:** - Use 2x M3 x 6mm screws - Insert screws through sensor PCB holes - Screw into the top of each spacer - Tighten evenly in a cross pattern 5. **Check sensor height:** - **Optimal distance:** 3-5mm from ground to sensor face - Too close: may scrape on uneven surfaces - Too far: reduced sensitivity - Adjust spacer length if needed (return to Step 7) 6. **Verify sensor orientation:** - Sensors should be parallel to ground - Sensors should be centered on chassis - All sensors should be at same height ### Quality Check - [ ] Line sensors are mounted securely on spacers - [ ] Sensors are 3-5mm from ground - [ ] Sensors are parallel to ground - [ ] Sensors are centered on chassis - [ ] Sensors face downward - [ ] All mounting screws are tight - [ ] Sensors do not interfere with wheels or ball caster **Note:** Sensor height is critical for line detection. Test on actual track and adjust if needed. --- ## Step 12: Connecting Motors to Shield ### Instructions 1. **Identify motor terminals:** - Each motor has 2 wires (usually red and black, or both same color) - Left motor wires - Right motor wires 2. **Identify shield motor terminals:** - **J11:** Motor 1 terminal (usually left motor) - **J12:** Motor 2 terminal (usually right motor) - Each terminal has 2 positions 3. **Prepare motor wires:** - If motors don't have wires pre-attached, solder wires to motor terminals - Use appropriate gauge wire (typically 22-24 AWG) - Solder one wire to each motor terminal - Ensure good solder joints (shiny, not cold/dull) - If wires are too long, consider shortening (leave some slack) - Strip wire ends if needed (about 5mm) - Twist stranded wire ends to prevent fraying 4. **Connect left motor to J11:** - Loosen both screws on J11 terminal - Insert one motor wire into first position - Insert other motor wire into second position - Tighten both screws firmly - Tug gently on wires to ensure secure connection 5. **Connect right motor to J12:** - Same procedure as J11 - Loosen screws, insert wires, tighten screws 6. **Cable management:** - Route motor wires neatly - Avoid wires near wheels or moving parts - Use cable ties to secure wires to chassis - Leave some slack for movement/vibration ### Quality Check - [ ] Wires are soldered securely to motor terminals - [ ] Solder joints are clean and shiny - [ ] Left motor connected to J11 - [ ] Right motor connected to J12 - [ ] All 4 terminal screws are tight - [ ] Wires are secure (gentle tug test) - [ ] Wires are routed away from wheels - [ ] Wires are secured with cable ties - [ ] Some slack in wires for vibration **Note:** Motor polarity determines rotation direction. If a motor runs backward during testing, simply swap its two wires at the terminal. --- ## Step 13: Connecting Ribbon Cable ### Instructions 1. **Identify connectors:** - **Line sensor connector:** Usually on sensor PCB - **Shield connector J1:** 2x10 pin header on shield 2. **Prepare ribbon cable:** - Identify pin 1 on both ends (usually marked with red stripe or arrow) - Check cable length - should reach from sensors to shield - Ensure cable is not damaged 3. **Connect to line sensors:** - Align ribbon cable connector with sensor connector - **⚠️ Match pin 1 markings! (Pin 1 is separated from the other pins in the socket)** - Press connector firmly until fully seated - Some connectors have a latch - ensure it clicks 4. **Route the cable:** - Route cable from sensors to shield - Avoid sharp bends - Keep cable away from wheels and moving parts - Leave some slack for vibration 5. **Connect to shield J1:** - Align ribbon cable connector with J1 on shield - **⚠️ Match pin 1 markings!** - Press connector firmly until fully seated 6. **Secure the cable:** - Use cable ties to secure ribbon cable to chassis - Ensure cable cannot get caught in wheels - Do not over-tighten cable ties (can damage ribbon cable) ### Quality Check - [ ] Ribbon cable connected to line sensors - [ ] Ribbon cable connected to shield J1 - [ ] Pin 1 orientation is correct on both ends - [ ] Both connectors are fully seated - [ ] Cable is routed neatly - [ ] Cable is secured with cable ties - [ ] Cable has some slack - [ ] Cable cannot interfere with wheels or moving parts **⚠️ CRITICAL:** Incorrect pin 1 orientation can damage the sensors or shield! --- ## Step 13: Final Checks Before Power-On ### Mechanical Checks - [ ] All screws are tight (motors, wheels, ball caster, boards, sensors) - [ ] Wheels rotate freely without rubbing - [ ] Ball caster rolls freely in all directions - [ ] No loose components - [ ] Chassis is stable ### Electrical Checks - [ ] All connectors are fully seated: - [ ] Shield to FRDM board (J1, J2, J5, J6) - [ ] Motors to shield (J11, J12) - [ ] Line sensors ribbon cable (both ends) - [ ] Battery to shield (J10) - [ ] No visible short circuits or solder bridges - [ ] All wires are secured and routed properly - [ ] No wires near moving parts (wheels) ### Component Orientation Checks - [ ] Shield is correctly oriented on FRDM board - [ ] LM339 ICs have correct orientation (notch alignment) - [ ] Diode D1 has correct polarity - [ ] XT60 connector has correct polarity - [ ] Ribbon cable pin 1 is correct on both ends ### Safety Checks - [ ] Battery is firmly secured - [ ] Switch S1 is in OFF position - [ ] Work area is clear of metal objects - [ ] Fire extinguisher nearby (recommended for LiPo batteries) - [ ] No damaged wires or components ### Documentation - [ ] Take photos of completed assembly (top, bottom, sides) - [ ] Note any modifications or issues - [ ] Record battery voltage before first use --- ## Step 15: First Power-On Test ### Pre-Power Checks 1. **Final visual inspection:** - Look for any obvious problems - Check all connections one more time - Ensure nothing is loose 2. **Prepare for test:** - Place car on a non-conductive surface - Elevate car so wheels don't touch surface (use a stand or blocks) - Have multimeter ready - Be ready to quickly turn off power if needed ### Power-On Procedure **⚠️ IMPORTANT:** Keep your hand on switch S1 to quickly turn off if needed! 1. **Turn on power:** - Switch S1 to ON position - Observe immediately 2. **Check for problems (first 5 seconds):** - [ ] **No smoke** → If smoke appears, turn OFF immediately! - [ ] **No burning smell** → If smell detected, turn OFF immediately! - [ ] **No excessive heat** → Touch components gently, turn OFF if very hot - [ ] **No sparks** → Turn OFF if sparks appear - [ ] **No unusual sounds** → Turn OFF if buzzing or popping sounds 3. **Check LEDs (if no problems detected):** - [ ] Power LED on shield is ON - [ ] Power LED on FRDM-MCXN947 is ON - [ ] Any status LEDs show expected state 4. **Measure voltages with multimeter:** - [ ] Battery voltage at XT60: ~7.4V (or current charge level) - [ ] 5V rail on shield: 5.0V ±0.25V - [ ] 3.3V on FRDM board: 3.3V ±0.15V 5. **Check components:** - [ ] Shield components are not excessively hot - [ ] DC-DC converter (U1) is slightly warm (normal) - [ ] Motor drivers (U2, U3) are cool or slightly warm - [ ] FRDM board is cool 6. **Turn off power:** - Switch S1 to OFF position - Wait 10 seconds - Check components for any residual heat ### If Everything is OK **Congratulations!** Your NXP Cup car hardware is assembled and powered correctly! ### Quality Check - [ ] Power-on successful with no issues - [ ] All LEDs functioning - [ ] Voltage measurements correct - [ ] No excessive heat - [ ] No smoke or unusual smells --- ## Assembly Complete! ✓ Your NXP Cup car is now fully assembled and ready for programming! --- ## Safety Reminders ### LiPo Battery Safety - ⚠️ **Never** short circuit battery terminals - ⚠️ **Never** puncture or damage battery - ⚠️ **Never** charge unattended - ⚠️ **Never** exceed 4.2V per cell when charging - ⚠️ **Always** use LiPo-specific charger - ⚠️ **Always** store in fireproof bag - ⚠️ **Always** dispose of damaged batteries properly ### Operational Safety - ⚠️ Keep fingers away from moving wheels - ⚠️ Ensure car cannot fall off table during testing - ⚠️ Test in safe area away from obstacles - ⚠️ Have emergency stop method ready - ⚠️ Wear safety glasses during assembly/testing ### Electrical Safety - ⚠️ Always turn off power before making connections - ⚠️ Never work on powered circuits - ⚠️ Check polarity before connecting battery - ⚠️ Disconnect battery when not in use - ⚠️ Keep liquids away from electronics --- **Next Steps:** - [Programming Guide →](programming.md) [← Shield Assembly](shield-assembly.md) | [← Back to Main](../tutorial.md)