The W1209 is an incredibly low cost thermostat controller with a lot of features. With this module you can intelligently control power to most types of electrical devices (like poultry egg hatch incubator) depending on the temperature read by the integrated high precision NTC temperature sensor. Although this module has an embedded microcontroller and no programming knowledge is required to program it. Three push buttons are available allows in configuring various parameters including ON & OFF trigger temperatures. The on-board relay is capable of switching up to 240V AC at 5A or 14V DC at 10A. The module has seven modes and can be programmed in each individual mode by following certain steps which will be discussed here later. The module runs on 12V DC supply. It finds applications in various automation projects and can be programmed according to our specific needs. The module is accurate up to 0.1°C and can control devices in temperature ranges from -50°C to 110°C. The board can work with a maximum of 240V AC at a maximum current of 5A and at 14V DC with a maximum current of 10A.
How to use the module?
Long pressing the SET button on the module will open up the various programmable settings on the module. There are total seven
programmable settings in the module, each of which will be discussed in detail here. Please note that long pressing the +/- buttons will reset all values to their default. The thermostat displays the default temperature on the seven segment display when no mode is selected. Apart from this, when the module is in any other mode where no input is given to the module for more than 5 seconds, it will return to the home screen and will display the room temperature.
To set the trigger temperature on the module press the set button once, the seven segment display will start flashing, use the +,- buttons to change the temperature with increments of 0.1°C and press the set button again to set the trigger temperature.
(i) PO mode: -
This mode can be accessed by long pressing the set button. Once the PO mode is visible press the set button again once. Now we are in a new window which displays two modes that can be navigated using the +,- buttons on the module. Suppose we have set the trigger temperature as 30°C and we choose the H or the hot mode in PO settings. To do this open PO mode press the set button again, use + or – button to navigate between the two modes, once H is selected press the set button again and you will return to home screen in a few seconds. Usually in these settings a heater is connected to the relay on the module, when the temperature is below the trigger temperature the module activates the relay and in turn the heater, as soon as the temperature is equal to the trigger temperature the relay turns OFF allowing the temperature to drop again and the same action is repeated until further instructions are give to the module. In the cold mode the relay is normally connected to an air conditioner or a fan, as soon as the temperature reaches the trigger temperature the relay starts, for instance if the trigger temperature is 30°C and the temperature exceeds the trigger temperature say the ambient temperature is 32°C, the relay will turn ON, in turn activating the fan which will turn OFF as soon as the temperature reaches 30°C.
(ii) P1 mode: -
This mode enables us to control the exact interval between the ON and OFF period of the relay. Foe example we want to turn OFF the relay immediately after the ambient temperature reaches 30°C (trigger temperature) and immediately turn it back if it drops below 30°C, we use this mode. We can manipulate this interval by programming the module, in the above case we are using the module in hot mode with the interval at 0.1°C. To access this mode long press the set button and navigate to P1 mode, press set to enter P1 mode and vary the temperature range using the + or – button, in the above case we had set the temperature interval at 0.1°C. This interval temperature is also known as backlash temperature.
(iii) P2 mode: -
This mode is used to set the maximum value that a user can set as trigger temperature, it is usually a safety precaution so that the user does not input a very high trigger temperature value. For example while using incubators, the eggs will only hatch when the device is set at a particular temperature, if by mistake the user sets the trigger temperature vey the eggs may get damaged, so to avoid such situations, this mode is made available. To access this mode long press the set button, navigate to the P2 mode and press the set button to access the P2 mode and select the maximum value of trigger temperature using the + and – buttons. Press set once the value is inputted.
(iv) P3 mode: -
This setting limits the minimum trigger temperature that the user can input. It is also a safety precaution to prevent the user from accidentally setting an extremely low trigger temperature. This mode can also be accessed and programmed in a way similar to the P2 mode.
(v) P4 mode: -
This mode is the error correction mode of the module. This mode is used to remove the difference between the displayed temperature and the actual ambient temperature. In other words this mode is used to calibrate the thermistor. We can make minor corrections to the temperature using this mode. To access this mode we need to press the settings button and navigate to the P4 mode, press the set button once and use the + and – buttons to calibrate the module accordingly. The correction range can be from -7°C to +7°C.
(vi) P5 mode: -
This is the delay mode, which means that we can control the time at which the relay reacts after reaching the trigger temperature, this ranges from 0-10 minutes. To access this mode long press the set button and navigate to P5 mode, press the set button once give the input using + and – buttons to set the time delay in minutes.
(vii) P6 mode: -
This is the alarm mode, this is set to OFF by default, in this mode an alarm in the form of three dashed lines is displayed on the seven segment display, and the relay is turned OFF till the temperature reaches below this value. To access this mode long press the set button and navigate to the P6 mode, press the set button once, the display will show OFF, use the +/- button to navigate to ON and press set, the alarm mode is now ON, now the display will show a temperature which you can change by using the + or – button, this is the alarm temperature which will be set by the user.