Bench testing & the test box

Never spin a weapon in open air. Every weapon test happens inside a containment box.¹

First power-up sequence

1. Weapon disconnected (phase leads unplugged or rotor removed). Wheels off the ground on a stand.
2. For a first-ever power-up, put a smoke stopper (e.g. VIFLY ShortSaver) between the battery and the robot — it cuts power on the current rush of a short before anything burns.²
3. Insert the removable link. Confirm the receiver binds and the failsafe test passes (TX off → drive stops).
4. Check drive direction and mixing: left stick → left side, forward is forward, invert switch works.
5. Check current draw with a watt meter if available; look for anything hot.
6. Power down (link out) before touching anything.

The test box

A box that contains a weapon failure — a shed tooth, a thrown fastener, or the whole rotor letting go.

• Carcass: 0.75” (19 mm) plywood is the standard and is enough to contain a beetleweight — no steel lining needed. Join the panels with steel brackets or wood blocks, not just screws into end grain.²
• Window: polycarbonate (Lexan / Makrolon) — never acrylic / Plexiglass, which shatters. Minimum 3/16” for a roof window with light testing; double 3/16” or 1/4” if you’ll hit hard or the window faces the weapon (arena standard is double 1/4”).²
• Don’t drill the polycarbonate — holes crater its impact strength. Retain it with slots or clamps.²
• Size: fits the whole robot with the lid closed.
• Lid: clamped, hinged-and-latched, or slotted. No antenna pass-through needed at 2.4 GHz — keep the TX outside, box closed.
• Some builders bolt the box to the bench or floor.

Loading and unloading (test box or arena)

Do this every time — the order is what keeps the weapon from spinning up while your hands are near it:²¹

1. Transmitter on, then set it aside.
2. Load the robot in.
3. Turn the robot on.
4. Remove the weapon lock.
5. Close the enclosure.
6. Pick the transmitter back up.

Unload in the exact reverse order (enclosure open → weapon lock in → robot off → robot out).

Weapon test procedure

1. Robot in the box, link out, weapon rotor clear.
2. Insert link, close and latch the lid.
3. Arm and spin the weapon up gradually to partial speed, listening for imbalance or rubbing. Spin down.
4. Increase toward full speed in steps. Note spin-up time and any ESC desync.
5. Spin down, wait for full stop, link out, then open.
6. Inspect the rotor, shaft, bearings, and fasteners after the first full-speed run and re-torque everything.

Events provide a test box in the pits; the same discipline applies there.³

References

Footnotes

1. NHRL Wiki (National Havoc Robot League) — pit safety, the test-box requirement, and weapon-arming procedure. ↩ ↩²

2. Ping, L., with L. Skotiniotis, I. Talbert & D. Tran. Beetleweights for Dummies (Fall 2025 revision) — builder-maintained beginner guide distributed via the NHRL Discord. Sections: Testing & Safety (Test Boxes, Testing Electronics); Note on Safety. ↩ ↩² ↩³ ↩⁴ ↩⁵

3. SPARC Robot Construction Specifications and Tournament Rules, v1.4, 2023 — safe activation/deactivation and pit conduct. ↩