Build · Electronics
Six components, one power path.
Every plastic-ant bot is the same circuit wearing a different chassis: battery → switch → ESCs → motors, with a receiver telling the ESCs what to do and a light telling the world it’s alive.
The power path
LiPo battery (XT30)
└─→ power switch / removable link ← the rules-required disconnect
├─→ dual brushed ESC ──→ left + right drive motors
├─→ weapon ESC ──→ weapon motor (wedges: skip)
└─→ power light ← visible from outside
receiver ← powered by the drive ESC’s BEC; signal wires to both ESCs
└─→ power switch / removable link ← the rules-required disconnect
├─→ dual brushed ESC ──→ left + right drive motors
├─→ weapon ESC ──→ weapon motor (wedges: skip)
└─→ power light ← visible from outside
receiver ← powered by the drive ESC’s BEC; signal wires to both ESCs
- Everything downstream of the switch. If the switch is off, nothing anywhere in the robot can move. That is the inspection test.
- Insulate every joint. Heat-shrink on every solder joint, no exposed terminals — inspectors look for this specifically.
- Keep the receiver antenna away from motors and carbon. Range problems at events are almost always antenna placement.
Soldering, honestly
Soldering is a 30-minute skill with a 30-year reputation. Practice on scrap wire for one evening before touching real parts: heat the joint, feed the solder into the joint (not the iron), and a good joint is shiny and cone-shaped. Middle schoolers: an adult must be present and involved — that’s a league rule, and lab days exist so nobody solders alone.
Fail-safe: the test that matters
Bind, then verify: power the bot in a test box, drive it, then turn the transmitter off. Every motor must stop within a second. If anything keeps moving, the fail-safe isn’t configured — and the bot will fail inspection. Most receivers set fail-safe from a button or via the bind procedure; do it once, verify it every event morning.
Before first power-up
- Polarity check every connector with a multimeter — reversed polarity kills ESCs instantly.
- No conductive debris in the chassis (shake test, then look).
- Battery secured, terminals insulated, nothing protruding into its bay.
- Weapon lock on.
- Then — and only inside containment — follow the functional safety test procedure, step by step.