NexvioraThe outcome
Use a documented board/chassis pairing and staged commissioning.
Hardware planning only. No physical build, electrical test or certification is claimed. Verify exact components and the current manufacturer manual.
Before you begin
- Romi chassis and specified motors
- Matching Romi 32U4 board
- Six matched AA NiMH cells (nominal 7.2 V total), suitable NiMH charger and USB cable
- Tools and experienced reviewer
Prepare with Bring a small robot to life carefully, Turn wheel speeds into robot motion.
Manufacturer-backed parts
| Part | What to verify | Reference |
|---|---|---|
| Romi chassis | Matching mechanical platform and motors | Manufacturer |
| Romi 32U4 board | Integrated drivers; verify revision/power limits | Manufacturer |
| Battery set | Six AA NiMH cells: nominal 1.2 V each, 7.2 V total. The board maximum is 10.8 V; this is a limit, not a target. | Manufacturer |
| Disconnect | Reachable motor-power interruption matching the circuit | Manufacturer |
No prices or physical compatibility tests are invented. The manufacturer manual governs electrical ratings and exact connections.
Build, observe, explain.
Review power
The manufacturer recommends six rechargeable AA NiMH cells, giving 7.2 V nominal. The board maximum input is 10.8 V, limited by its motor drivers. VREG supplies regulated 5 V; its available current depends on input and conditions, so do not assume every companion computer is compatible. Check the actual revision, load and switch behavior.
Expected: Reviewed diagram and part-number checklist.
Wire unpowered
With batteries and USB disconnected, follow the manufacturer diagram: battery negative to GND, battery positive through the documented VBAT protection and switching circuit to VSW, then onboard drivers to motor connections. USB powers logic even when the battery switch is off, so switch-off alone does not prove the entire board is unpowered. Never feed VSW into host GPIO.
Expected: Inspection matches the manufacturer diagram. Functional overview is not a pinout substitute.
Commission in stages
Use matched cells and a charger designed for NiMH; remove cells for charging unless the manufacturer explicitly provides a charging circuit. Inspect polarity and stop using damaged, leaking or overheated cells. Test logic first, then brief low-speed lifted wheels. Confirm motor power actually stops through the accessible disconnect before isolated floor testing.
Expected: Recorded neutral startup, polarity and timeout criteria. No physical test is claimed.
Troubleshooting
- Different revisions
- Verify current diagrams; do not infer pin compatibility.
- Disconnect stops only host
- Verify motor-power interruption independently.
Take it further
- Add encoders and bounded serial feedback.
- Model the platform before writing a host bridge.
Documentation and next steps
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