Check parts on arrival
Do this the day the parts arrive, while you can still return them. Record the result (pass or fail and why) in the build record. A part that fails receiving inspection never goes into a robot.
Every part
- [ ] The part number on the part matches the order and the BOM.
- [ ] No transport damage: cracked housings, bent pins, crushed corners on the box.
- [ ] Note the lot or batch number if there is one (photo of the label).
Electronics
| Part | Check | Fail if |
|---|---|---|
| ZED-F9P GNSS board | The u-blox module's laser marking is sharp and the board maker's name is printed on the PCB; connect it over USB and read the firmware version | Blurry or printed (not etched) marking; module reports an unknown or odd firmware |
| Raspberry Pi 5 | Boots from a known-good card; vcgencmd get_throttled reads 0x0 with the official PSU |
Doesn't boot; throttling with the official PSU |
| IMU (BNO085) | Detected on I²C at address 0x4A or 0x4B | Not detected; wrong chip ID |
| Fuses | Rating printed on the fuse matches the wiring drawing; the body is the brand you ordered | Missing or smudged rating; a different brand to the listing |
| STOP button | Pressing latches it; twisting releases it; contacts open when pressed (measure with a multimeter) | Doesn't latch; contacts close instead of open (wrong type: must be normally closed) |
Batteries
Lithium batteries
Inspect batteries outdoors or on a non-flammable surface. Never charge a pack that is swollen, dented, warm, or smells sweet. Put it in a metal box outside and contact the seller.
- [ ] No swelling: the pack sits flat and the case isn't bulging.
- [ ] Open-circuit voltage is within the "storage" range for its chemistry (for a 7S Li-ion pack, about 25–27 V; the full range is 21–29.4 V). Below 21 V: don't charge it.
- [ ] The connector matches the wiring drawing, and its polarity is right (measure; don't trust wire colours).
- [ ] The BMS label and UN38.3 paperwork are present.
Mechanical (H2: a used mower)
- [ ] Wheels turn freely by hand with the motors unplugged; no grinding.
- [ ] The blade disc and guard are intact: no cracks, nothing bent.
- [ ] The rain seals are present and not perished.
- [ ] The dock's contacts are clean and springy.