A greenhouse controller
The relay closes when the DS18B20 passes 28 °C; an ultrasonic sensor measures distance too.
buttonds18b20hc_sr04ledrelay_1chssd1306_i2c
Actuator
Relay SRD-05VDC (on-board, NPN driven)
relay_1chGPIO
Why this support circuit is added
5 V relay; the coil is always fed from the 5 V rail.
Grounded in the catalog and golden patterns (real open-source circuits). Every auto-inserted part comes with a reason.
Support circuit added automatically2
Using this part in a project adds the circuit below, each element with its reason.
NPN transistor driver
COIL2 → MCU
The coil draws 70 mA+, beyond an MCU pin (40/12 mA max); an NPN drives it.
Flyback diode
COIL1 · COIL2
Clamps the back-EMF when the coil switches off; without it the transistor dies.
InterfaceGPIO
- Catalog id
- relay_1ch
- Category
- Actuator
- Protocol
- GPIO
- Logic level
- Unrestricted (uses the board rail)
Firmware detection0
No library reveals it — add it from the module checklist in your project.
Examples using this part
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