Relay + lamp

The relay + lamp kit is a high-trigger relay module with a lamp wired through its contacts, both fed from the same 5 V supply. It costs $13 and is for switching light: a night light that is actually bright, a timed lamp, or a light source for the light sensor in its zone. Wire vcc to 5 V, gnd to ground and sig to a GPIO — sig high lights the lamp.

What's inside

Part	Qty	Price each
Relay module	1	$4
Lamp	1	$5
Total	2	$9

The relay module switches the lamp's current; its coil takes ~72 mA from the 5 V rail and its contacts carry the load, so the GPIO stays safe.
The lamp is the load; in the simulator it lights its zone, and light sensors there read it on top of daylight.

Exposed pin	Inside the kit
vcc	`relay:DC+`
gnd	`relay:DC-`
sig	`relay:IN`

vcc feeds the relay coil and the switched loop (DC+ → COM → NO → lamp+ → lamp− → DC−), so it must be 5 V. sig is high-trigger: a high GPIO closes the contacts. The kit has no chain ends.

Wiring it in circuit.py

circuit.py

from wiring import *

pi = Pi()
lamp = kits.RelayLamp()

pi.V5 >> lamp.vcc        # relay coil and switched supply are both 5 V
lamp.gnd >> pi.GND
pi.GPIO17 >> lamp.sig    # high = light on

Driving it in main.py

main.py

from gpiozero import OutputDevice
from time import sleep

lamp = OutputDevice(17, active_high=True, initial_value=False)

while True:
    lamp.on()
    sleep(1)
    lamp.off()
    sleep(1)

Why buy the kit

Loose parts cost $4 + $5 = $9.00, against $13 — $4.00 for the switched loop assembled. The same job by hand is a relay, a lamp and four wires with one easy mistake (COM and NC swapped, leaving the lamp on in reverse); the kit wires COM to the supply and NO to the lamp for you. The relays primer has the full picture.

Simulator vs real hardware

Contacts close about 10 ms after sig goes high and open about 5 ms after it falls, so a blink pattern still comes out with the lamp's own small delay.
On the board the lamp is a 5 V, 100 mA stand-in; in its zone it adds the lux set by the inspector, scaled by (V ÷ 5 V)², so a light sensor in the same room sees it — useful for testing a night-light loop.
The relay gives on/off only; for dimming use a PWM-capable output device instead.