> For the complete documentation index, see [llms.txt](https://ask.simplehw.eu/kb/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://ask.simplehw.eu/kb/simple-api-6-generation/modes/wifi-user-modes/temperature-change-alert-wifi.md).

# Temperature change alert WiFi

Temperature delta alert WiFi is similar to the original mode as it sends an alert every time the measured temperature is above the predefined temperature delta. The delta is encoded in *SimpleTemp.* The mode-specific event is sent with 3 MAC addresses for better localisation precision.

Temperature change alert WiFi

**Hex value:** 0x1C

**Use cases:** Monitoring any environment that requires constant temperature in a certain range; labs, factories, warehouses, swimming pools and more

**Devices that support this mode:** SimplePack Plus

**Required sensors:** Either temperature sensor (ambi or precise, precise is preferable), WiFi module

**Mode-specific deltas:**

**Deltas** are mode-specific register values different from *register default values*.

| **Register (hex)** | **Default (hex)** | **Delta (hex)** | **Delta information**                  |
| ------------------ | ----------------- | --------------- | -------------------------------------- |
| 0x0D               | 0x00              | 0x40            | Temperature sent with appended payload |
| 0x34               | 0x00              | 0x43            | Temperature measuring turned on        |

**Mode-specific events (uplink messages):**

For more information on what uplink messages (***mode-independent events***) and additional data from various sensors in the device (***appended payload***) can be sent regardless of mode and how to fine-tune message behavior (***alerts***), see *Mode-independent information and events.*

| **Hex** | **Event name**                        | **Alert** | **Event information**                                            |
| ------- | ------------------------------------- | --------- | ---------------------------------------------------------------- |
| 0xB6    | Temperature delta alert with WiFi 1/2 | 1         | <p>Temperature above the delta,<br>sent with 3 MAC addresses</p> |
| 0xB7    | Temperature delta alert with WiFi 2/2 | 1         |                                                                  |

**Registers relevant for this mode:**

| **Hex** | **Register name**              | **Default value (hex)**                       |
| ------- | ------------------------------ | --------------------------------------------- |
| 0x2F    | Temperature delta              | 2°C (0x08)                                    |
| 0x34    | Temperature measurement period | 0 seconds (0x00), **delta: 3 minutes (0x43)** |
| 0x4D    | Temperature detection delay    | 0 seconds (0x00)                              |

**Similar modes:**

| **Hex** | **Mode name**                        | **Description**                                      |
| ------- | ------------------------------------ | ---------------------------------------------------- |
| 0x11    | Temperature delta alert              | Original version of Temperature delta alert, no WiFi |
| 0x43    | Temperature delta alert WiFi Atlas   | WiFi Atlas version of Temperature delta alert        |
| 0x58    | Temperature delta alert WiFi Precise | WiFi Precise version of Temperature delta alert      |

**Switching to mode, arming and disarming information:**

Follow the *Basic Operations With SimpleHw Devices guide*, where you can also find information about LED behavior, relevant Sigfox messages and more.

Here’s what’s important for **Temperature delta alert WiFi** messages:

* To set this mode, the downlink needs to include this mode register setting: **011C**
* The uplink messages need to begin with the mode hex as the first byte: **1C**
* When arming the device, you should see this message: **1C10**
* When the device is armed, it should send you these two bytes: **1C11**
* If you disarm the device via long press, you should receive this message: **1C14**