LED 0805 Resistor Value

flux

For a 2×8 matrix = 16 LEDs, don’t drive all LEDs directly one-pin-per-LED unless you have lots of GPIO. Use a multiplexed matrix:
  • 2 row lines
  • 8 column lines
  • 16 LEDs
  • 8 current-limiting resistors, usually one per column
That uses 10 GPIO total.
Typical wiring:
Text
ROW1  ── LED LED LED LED LED LED LED LED ── columns
ROW2  ── LED LED LED LED LED LED LED LED ── columns

COL1 COL2 COL3 COL4 COL5 COL6 COL7 COL8
Use one resistor per column, e.g.:
Text
ESP32 GPIO column pin ── 150Ω to 330Ω ── LED column
Then scan rows quickly:
  1. Enable row 1.
  2. Set the 8 column pins for row 1 pattern.
  3. Wait ~0.5–2 ms.
  4. Disable row 1.
  5. Enable row 2.
  6. Set the 8 column pins for row 2 pattern.
  7. Repeat forever.
For ESP32 at 3.3 V with red 0805 LEDs, I’d start with:
  • 220 Ω if multiplexing and you want decent brightness
  • 330 Ω for safer/lower current
  • 470 Ω–1 kΩ if they only need to be dim indicators
Important: because each row is only on ~50% of the time, each LED appears dimmer than a continuously driven LED. You can compensate with slightly lower resistors, but keep ESP32 GPIO current limits in mind. For a clean design, use transistor/MOSFET row drivers if more than a few LEDs can be on at once.
Pick LEDs and resistors
Show LED5 schematic
Add row drivers
Compare resistor currents
Check LED5 datasheet
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can the data D+ and D- lines connecting usb c to the esp32 module have vias in their traces?
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