From e1c5d0097243a286ba57a6a869a55526cbb18c0c Mon Sep 17 00:00:00 2001 From: jessikitty Date: Fri, 25 Sep 2026 01:28:22 +1000 Subject: [PATCH] Add separate-ground LED wiring diagram Four wires, no shared return junction, so the series-LED failure mode cannot occur. --- docs/wiring-leds-separate.svg | 56 +++++++++++++++++++++++++++++++++++ 1 file changed, 56 insertions(+) create mode 100644 docs/wiring-leds-separate.svg diff --git a/docs/wiring-leds-separate.svg b/docs/wiring-leds-separate.svg new file mode 100644 index 0000000..fc6aaa7 --- /dev/null +++ b/docs/wiring-leds-separate.svg @@ -0,0 +1,56 @@ + +LED wiring with separate ground pins - recommended +Board B GPIO25 goes through a 220 ohm resistor to the red LED pair and returns to its own GND pin. Board B GPIO26 goes through a 100 ohm resistor to the green LED pair and returns to a different GND pin. Four wires total and the two circuits never touch each other, so neither can end up in series with the other. + + + + + +BOARD B +receiver.ino + +GPIO 25 +GND (a) +GPIO 26 +GND (b) + + +220Ω + + +RED pair +long leg faces this side + + + + + +100Ω + + +GREEN pair +long leg faces this side + + + + +Four wires. The two loops never touch each other anywhere. + + +Why this version cannot fail the same way +There is no shared junction to get wrong. Each LED has one path out and one path back, so +neither can end up in series with the other. GND (a) and GND (b) are different physical pins +but the same net inside the board - that is fine, and it is what makes this safe to do. +