Prepare
Power off, remove the batteries, inspect the Mod5 attachment, and collect every part with a Tech Leader.
G-LAB BOT · MODIFICATION 01
Light Up
Light Up
Your Bot.
Add two bright LED headlights with the Mod5 attachment, then install two red tail lights using the rear holes or mounts already on your vehicle.
2 Headlights2 Tail LightsParallel CircuitsTech Leader Guided
MOD5 LIGHT MOUNT
YOUR FIRST MODIFICATION
Two Circuits. One Brilliant Bot.
You will build a 5 V headlight circuit and a separate 3.3 V tail-light circuit. Both use the existing common ground, but the 5 V and 3.3 V positive rails must never touch.
Headlights
Extend the existing 5 V and ground rails, then build two white LED branches in parallel.
Tail Lights
Create a separate 3.3 V rail from the ESP32 3V3 pin and build two red LED branches in parallel.
Verify
A Tech Leader checks polarity, resistance, rail separation, and voltage before power is restored.
Tech Leader checkpoint: Do not install batteries or switch on the Bot until a Tech Leader has inspected every connection and measured both rails.
COLLECT WITH A TECH LEADER
Your Modification Kit
Use the same 170-pin mini breadboard already on your G-Lab Bot. Keep all existing motor and ESP32 wiring in place.
×1
Mod5 Attachment
Front mount with two circular headlight openings.
×2
White LEDs
One LED for each headlight branch.
×2
Red LEDs
One LED for each rear tail-light mount.
×4
100 Ω Resistors
One resistor in series with each LED—not one shared resistor.
×1
170-Pin Mini Breadboard
Use unused connected rows to distribute 5 V, 3.3 V, and ground.
As needed
Dupont Jumper Wires
Use colors consistently: red for positive rails and black or blue for ground.
LED ANODE (+)Usually the longer leg. It faces the positive rail through a 100 Ω resistor.
LED CATHODE (−)Usually the shorter leg and flat side. It returns to the common ground rail.
LED markings can vary. Ask a Tech Leader to confirm polarity before bending or trimming any leads.
THE BIG IDEA
Build Each Pair in Parallel
In a parallel circuit, each LED has its own path from the positive rail to ground. This gives both lights the same supply voltage and lets each branch use its own current-limiting resistor.
- Each branch gets one LED.
- Each branch gets one 100 Ω resistor.
- Both branches begin on the same positive rail.
- Both branches return to the same ground rail.
POSITIVE RAIL
Branch A100 ΩLED
Branch B100 ΩLED
COMMON GROUND
HEADLIGHTS · 5 V
Install the Mod5 Headlights
The existing 5 V source comes from the L298N Motor Driver. Extend that existing 5 V rail and the existing ground rail onto unused connected rows of the 170-pin mini breadboard.
Before touching wiring: Switch the Bot off, disconnect USB, and have a Tech Leader remove both 18650 batteries.
1
Tech Leader Check
Identify the existing rails
With all power removed, ask a Tech Leader to point out the existing 5 V rail from the L298N Motor Driver and the existing ground rail. Do not move the wires already powering the ESP32.
2
Breadboard
Extend 5 V and ground
Use jumper wires to copy 5 V and ground to two unused connected groups on the 170-pin mini breadboard. Label or color-code them so the new 5 V group cannot be confused with the future 3.3 V group.
3
Mechanical
Prepare and mount Mod5
Ask a Tech Leader to confirm the forward-facing orientation. Seat one white LED in each circular opening, route the leads without pinching them, then secure the Mod5 attachment in its designated front mounting position.
4
Parallel Branch A
Wire the left headlight
Connect the extended 5 V rail → one 100 Ω resistor → LED anode (+). Connect the LED cathode (−) to the extended ground rail.
5
Parallel Branch B
Wire the right headlight
Repeat with a separate path: 5 V rail → a second 100 Ω resistor → LED anode (+) → LED cathode (−) → ground. Do not share one resistor between the two LEDs.
EXISTING SOURCEL298N 5 V Rail
5 V POSITIVE BUS
LEFT100 ΩANODE +CATHODE −
RIGHT100 ΩANODE +CATHODE −
COMMON GROUND BUS
The branches share the 5 V source and ground—but each white LED has its own 100 Ω resistor.
TAIL LIGHTS · 3.3 V
Add a Separate 3.3 V Rail
Use the ESP32 pin labeled 3V3 to establish a new 3.3 V rail on an unused connected group. The tail lights use this new rail and the same common ground as the rest of the Bot.
Never connect 3V3 to 5 V.The two positive rails must stay separate. Only their ground reference is shared.
6
Tech Leader Check
Locate the ESP32 3V3 pin
Keep all power removed. Ask a Tech Leader to identify the pin printed 3V3 on your exact ESP32 board and confirm that the selected breadboard group is unused.
7
3.3 V Rail
Create the new positive rail
Run one jumper from the ESP32 3V3 pin to the unused connected breadboard group. Mark this group 3.3 V. Extend the existing common ground to a nearby unused connected group if needed.
8
Rear Mounts
Install both red LEDs
Place one red LED in each existing rear hole or mount. Route the leads away from the wheels, motor shafts, battery holder, and sharp chassis edges.
9
Parallel Branches
Wire both tail lights
For each tail light, make a separate path: 3.3 V rail → its own 100 Ω resistor → LED anode (+) → LED cathode (−) → common ground.
10
Wire Management
Secure the new wiring
Leave enough slack for service, but no loose loops near moving parts. Ask a Tech Leader to help secure wires without crushing insulation or shorting exposed LED leads.
NEW SOURCEESP32 3V3 Pin
3.3 V POSITIVE BUS
LEFT REAR100 ΩANODE +CATHODE −
RIGHT REAR100 ΩANODE +CATHODE −
SAME COMMON GROUND BUS
The tail lights share ground with the rest of the Bot. Their 3.3 V positive bus must never touch the 5 V positive bus.
TECH LEADER FINAL CHECK
Inspect. Measure. Then Power On.
A successful modification is not just bright—it is safe, organized, and easy to troubleshoot.
Resistance
Confirm four 100 Ω resistors are present—one in every LED branch.
Polarity
Confirm every anode faces its resistor and every cathode returns to ground.
Rail Separation
Use continuity mode with power removed to make sure 5 V and 3.3 V are not connected together.
Voltage
A Tech Leader temporarily powers the Bot and measures about 5 V and 3.3 V on the correct rails.
Light Test
Both headlights and both tail lights should illuminate evenly without flicker or excessive heat.
Drive Test
Confirm the wheels move freely and no new wire can touch a motor shaft, wheel, or caster.
Stop immediately if…
an LED stays darkone resistor or wire becomes warmthe ESP32 resetsyou smell hot plasticthe measured rail is incorrect
Switch off, remove the batteries, disconnect USB, and ask a Tech Leader to troubleshoot. Never move a wire while the Bot is powered.
MODIFICATION 01 COMPLETE
Your Bot Can Now See—and Be Seen.
You built two parallel LED systems, extended a 5 V rail, created a separate 3.3 V rail, shared a safe ground reference, and practiced professional testing habits.