Lab Safety¶

Sign-off required

You complete the safety briefing and sign off before Lab 1. Without it you do not handle batteries or run powered motors. Lab 1 is a full motion lab — the sign-off happens before it, not during it. There is no version of this that happens retroactively.

Instructor: verify against local policy

The guidance below is standard practice for this class of hardware. Your institution's EHS office has its own rules, emergency numbers, and incident reporting procedure, and those take precedence. Replace every TODO here with the local specifics before this page goes live.

Emergency information¶


Emergency number	TODO
Lab supervisor	TODO — name, phone
Nearest fire extinguisher	TODO — location, type
Fire blanket	TODO — location
LiPo fire bucket (sand)	TODO — location
Eye wash / first aid kit	TODO — location
Incident reporting	TODO — procedure

Know these locations before you need them. You will be asked.

Lithium polymer batteries¶

LiPo packs store a lot of energy and have no internal protection circuit. They are safe when treated correctly and genuinely dangerous when not.

Always¶

Inspect before every use. Puffed, swollen, dented, or punctured pack → stop, bag it, tell a TA. Do not charge it, do not use it.
Charge in a LiPo-safe bag, on a non-flammable surface, in the designated charging area.
Charge in balance mode at the correct cell count. A 2S pack charged as 3S will be destroyed and may ignite.
Stay in the room while charging. No exceptions, no "just stepping out".
Store at storage charge (~3.8 V/cell), not full, if the pack sits more than a few days.
Disconnect the pack when you are not actively testing.

Never¶

Never discharge below 3.0 V per cell (6.0 V on a 2S pack). Below this the pack is permanently damaged and unsafe to recharge.
Never short the leads. A 5200 mAh pack across a dropped screwdriver will weld it and start a fire in under a second.
Never charge a pack that is warm from use. Let it cool.
Never leave a pack loose in a bag with metal objects.
Never put a damaged pack in a normal bin.

If a pack vents or catches fire¶

Do not use water. Do not use a CO₂ extinguisher on the cell itself.
Move people away. Lithium fires produce toxic smoke — clear the area.
Smother with sand if it can be done safely from a distance.
Pull the fire alarm and call TODO.
A vented pack that has stopped burning is still dangerous. Do not touch it.

Soldering¶

Irons reach 350 °C and look identical hot or cold. Assume hot.
Iron in its stand, every time you put it down. Never on the bench.
Solder in a ventilated area — flux fumes are a respiratory irritant.
Eye protection when clipping leads. Trimmed wire ends travel fast.
Never solder a circuit that is powered, and never solder near a connected LiPo.
Wash your hands afterwards.

Powered motors and moving robots¶

Wheels off the bench surface when testing on the bench.
Tie back long hair; no loose sleeves, cords, or lanyards near a driveline.
Keep fingers clear of gears, wheels, and shafts under power.
Every robot needs a way to stop it without chasing it — a reachable kill switch or battery connector.
Announce it before you power up: "powering up". Your bench partner should not be surprised.

Electrical¶

Check polarity twice before connecting a supply. Reversed polarity destroys parts instantly and silently.
Rewire only with power disconnected, not just switched off.
Do not exceed 3.3 V on any ESP32 GPIO. 5 V sensors need a level shifter.
Lift the car so all four wheels spin free before the first powered test.
Keep liquids off the bench entirely. No exceptions for water bottles.

Housekeeping¶

Clear bench at the end of every session. Loose wire offcuts short things.
Damaged or suspect parts go to a TA with a note, not back in the bin.
Batteries go back to the charging station at storage charge, in their bags.

Reporting¶

Report every incident, including near-misses and ones where nothing was damaged. This is not punitive — it is how the next cohort gets a safer lab.

TODO — state the reporting procedure and who to tell.