What it is
The ShillehTek W1209 12V Digital Temperature Controller Thermostat Switch Module is a compact thermostat switch module for DIY heating/cooling automation. It shows real-time temperature on a bright 3-digit LED display and can drive a relay based on your setpoint—useful for incubators, brewing temperature control, and basic overheat protection projects (including Arduino or Raspberry Pi builds where you want a standalone temperature relay controller).
Pins
Pin labels and terminal names can vary slightly by board revision. Refer to the silkscreen labels on the module and the listing photos for the exact power, sensor, and relay output connections before wiring.
Technical Specifications
| Item | Value |
|---|---|
| Module / Controller | W1209 digital temperature controller (thermostat switch module) |
| Supply voltage | 12V |
| Display | 3-digit LED temperature display |
| Control modes | Heating & Cooling modes (relay switches based on setpoint) |
| Hysteresis | Adjustable (helps prevent rapid relay cycling) |
| Temperature sensor | Waterproof NTC probe, ~50 cm cable |
| Relay rating (onboard) | Up to 10 A (120 VAC / 14 VDC) |
Frequently Asked Questions
What power supply does the W1209 temperature controller use?
This W1209 module is a 12V digital temperature controller. Use a suitable 12V supply for the controller and wiring.
Can the W1209 control heating and cooling (heater or fan)?
Yes. The firmware supports HEATING and COOLING modes so the relay can switch a heater when cold or a fan when hot based on your setpoint.
What sensor comes with the ShillehTek W1209 module?
It ships with a waterproof NTC temperature probe with an approximately 50 cm lead, suitable for many DIY temperature control setups.
How do I prevent the relay from rapidly turning on and off?
Use the adjustable hysteresis setting. Adding hysteresis creates a small temperature band around the setpoint to reduce rapid cycling.
Can I use the W1209 with an Arduino or Raspberry Pi project?
Many makers use it as a standalone thermostat relay module alongside Arduino or Raspberry Pi builds. Wire it as an independent temperature switch (it does not require a microcontroller to function).