Output Control
Two switches, one tap each
Page 40 turns two spare GPIOs into tappable switches: GPIO 9 and GPIO 15, ready to drive a relay module, a buzzer or an LED. Each channel has a manual switch and a state lamp, and both can be controlled over the serial console, MCP or the HTTP API.
β A reboot always returns both channels to off. Forgetting the previous state is deliberate: powering up with a heater or relay already energised is a real safety problem.
On-screen interface
A recreation of this page on the 2.41-inch AMOLED display (600 Γ 450). Actual interaction and layout follow the latest firmware.
Key capabilities
Two channels
GPIO 9 and 15 switch independently.
Off after reboot
State is not restored, so nothing energises at power-up.
Remote control
Serial out commands, MCP tools and the HTTP API.
Mains isolation
Relays run from their own 5V supply, sharing only ground.
Technical specs
Typical scenarios
Grow light timer
Switch the lamp on manually when page 41 reports too little light.
Remote power cycle
Put a relay in front of a camera or router and cycle it from anywhere.
Related commands
page 40 Open output control out Show both channel states out 9 on | off | tog Drive channel 1 (GPIO 9) out 15 on Drive channel 2 (GPIO 15)
- β Mains loads need their own supply: power the relay from 5V, share only ground, never from 3V3.
- Prove the logic with a 12V lamp first; only then move to 220V.
- GPIO 16 now belongs to the servo PWM (page 45), so do not use it as an output.