Raspberry Pi IR Illuminator PCB Design
I have a board outline and thru-hole LED locations in a DXF that I will import manually.
Please help me create a small PCB module for a Raspberry Pi IR illuminator ring with the following requirements:
High‑level function
This board powers six 5 mm 850 nm IR LEDs from a Raspberry Pi 5 V rail.
The LEDs are arranged as two rows of three LEDs each (total 6 LEDs).
The LEDs are driven as three identical branches, each branch being:
5 V → series resistor → 2× IR LEDs in series → MOSFET → GND.
A single MOSFET provides global on/off (and optional brightness control via PWM from a GPIO) for all three branches at once.
The board connects to the Pi via a 3‑pin JST female right‑angle connector: 5 V, GND, and LED_CTRL (GPIO).
Schematic requirements
Create a schematic with:
Net names: 5V_IN, GND, and LED_CTRL.
Six identical IR LED symbols (call them D1–D6). Use generic 5 mm IR LED symbols (through‑hole footprints, ~1.0 mm lead drill is fine; I will adjust footprints later).
Three current‑limiting resistors, R1–R3, all 120 Ω, 1/4 W, through‑hole.
One small N‑channel MOSFET used as a low‑side switch, labeled Q1.
One 3‑pin JST‑XH or JST‑PH female right‑angle connector (footprint with 3 pins in a row), labeled J1.
Wire the LEDs and resistors as three identical series branches:
Branch 1: R1 → D1 → D2 in series.
Branch 2: R2 → D3 → D4 in series.
Branch 3: R3 → D5 → D6 in series.
All three R1/R2/R3 “top” ends connect to 5V_IN.
The bottom end of each LED pair (D2, D4, D6) ties together to a node called LED_RETURN.
MOSFET connection:
Use a small N‑channel logic‑level MOSFET, e.g. a generic SOT‑23 part suitable for at least 200 mA continuous current and low Rds(on) at 3.3 V gate drive (you can pick a commonly used part).
Connect MOSFET source to GND.
Connect MOSFET drain to LED_RETURN.
Connect MOSFET gate to LED_CTRL through a ~100 Ω series resistor (call it R_GATE).
Add a 100 kΩ gate‑to‑source pulldown resistor (R_PD) to keep the LEDs off when the GPIO is high‑impedance.
Connector pinout:
J1 pin 1: 5V_IN.
J1 pin 2: GND.
J1 pin 3: LED_CTRL.
Please label these clearly in the schematic and silkscreen (5V, GND, CTRL).
Values and notes:
Assume each IR LED has Vf ≈ 1.2–1.3 V at 20 mA. We will run each 2‑LED string at ~20–22 mA from 5 V with 120 Ω.
R1–R3: 120 Ω, through‑hole, 1/4 W, metal film, 1–5% tolerance.
R_GATE: 100 Ω, 0805 SMD.
R_PD: 100 kΩ, 0805 SMD.
Total current at 5 V is about 60–70 mA for all three branches together.
PCB / footprint requirements
For now, please place all components (LEDs, resistors, MOSFET, connector) off to one side of the board in a compact group so I can manually move them to match my imported DXF hole pattern.
Footprints:
LEDs D1–D6: through‑hole 5 mm LED footprint, about 2.54 mm lead pitch, 0.9–1.0 mm drill.
R1–R3: through‑hole axial resistor footprint suitable for a Yageo MFR‑25 style 1/4 W resistor (body ≈ 6.3 × 2.4 mm, lead spacing ≈ 7.5–10 mm, 0.9–1.0 mm drills).
Q1: SOT‑23 footprint.
R_GATE, R_PD: 0805 SMD.
J1: 3‑pin JST‑XH (or JST‑PH) right‑angle THT footprint, 2.5 mm or 2.0 mm pitch.
Layout guidance:
Do not try to align components to my DXF; just ensure the three LED pairs and their resistors are clearly grouped so I can drag them into position.
Route simple, wide traces for 5V_IN and GND (for example, 0.5–1.0 mm width) between the connector and the LED branches.
Keep the MOSFET and its small SMD resistors close together, and tie the LED_RETURN node clearly to the three LED branches.
Please:
Generate the schematic, assign these footprints, connect all nets as described, and then switch to PCB view and place the parts in a clean cluster near the board edge so I can manually align them with the imported DXF LED holes and outline.
After you do that, summarize the netlist and the part choices so I can double‑check before routing.
I will handle:
Importing the DXF for outline and LED holes.
Final component placement (especially LEDs) and detailed routing.
Thought for 1 min
I've made a plan, and started work on it.
Ok plan sounds good, proceed.
Thought for 1 min 4 sec
I've made a plan, and started work on it.
Have you started? I don't see anything on the schematic?
Thought for 36 sec
No — I checked the live project and the requested IR illuminator schematic has not been created; the current schematic still only has L1, C1, R1 and zero nets. This appears to be a published NextPCB template that you don’t have edit access to, so use this link to start an editable project with the same build request pre-filled: Create Raspberry Pi IR Illuminator Ring Project. Flux project links with pre-filled prompts are the right path when the current project is not editable .
Check edit access
Explain blank schematic
Fix permissions
Inspect schematic
