In light of some questions about how to pass data to Cayenne via MQTT, and knowing that the table in our documentation is incorrect/showing not-yet-released items, I wanted to share the following table to help with building `virtualWrite()`

statements to pass data to Cayenne.

`virtualWrite()`

expects a parameter format like:

`virtualWrite(mqtt_channel_number, value, "type value", "unit value")`

You may have noticed that we have shorter functions like `luxWrite()`

that only need two parameters because they know the type and unit values already, but they are ultimately calling virtualWrite() and will not be covered here.

A few quick examples:

**Pass temperature value 25.2 in Celsius to MQTT Channel 2**

`virtualWrite(2, 25.2, "temp", "c")`

**Pass generic value 17.222 to MQTT Channel 6**

`virtualWrite(6, 17.222, "analog_sensor", "null")`

**Digital 2-state value 1 on channel 5:**

`virtualWrite(5, 1, "digital_sensor", "d")`

```
+------------------------------------+------------------+---------------------+------------+---------------------+
| Data Type | Type Value | Unit | Unit Value | Widgets |
+------------------------------------+------------------+---------------------+------------+---------------------+
| Digital Actuator | digital_actuator | Digital (0/1) | d | Button |
| Analog Actuator | analog_actuator | Analog | null | Slider |
| Digital Sensor | digital_sensor | Digital (0/1) | d | 2-State |
| Analog Sensor | analog_sensor | Analog | null | gauge, value, graph |
| Acceleration | accel | Acceleration | g | gauge, value, graph |
| Barometric pressure | bp | Pascal | pa | gauge, value, graph |
| Barometric pressure | bp | Hectopascal | hpa | gauge, value, graph |
| Battery | batt | % (0 to 100) | p | gauge, value, graph |
| Battery | batt | Ratio | r | gauge, value, graph |
| Battery | batt | Volts | v | gauge, value, graph |
| Carbon Dioxide | co2 | Parts per million | ppm | gauge, value, graph |
| Carbon Monoxide | co | Parts per million | ppm | gauge, value, graph |
| Counter | counter | Analog | null | gauge, value, graph |
| Current | current | Ampere | a | gauge, value, graph |
| Current | current | Milliampere | a | gauge, value, graph |
| Energy | energy | Killowatt Hour | kwh | gauge, value, graph |
| External Waterleak | ext_wleak | Analog | null | gauge, value, graph |
| Frequency | freq | Hertz | hz | gauge, value, graph |
| Gyroscope | g | Rotation per minute | rpm | gauge, value, graph |
| Gyroscope | g | Degree per second | dps | gauge, value, graph |
| Liquid | liquid | Liter | l | gauge, value, graph |
| Liquid | liquid | Milliliter | ml | gauge, value, graph |
| Luminosity | lum | Lux | lux | gauge, value, graph |
| Luminosity | lum | Volts | v | gauge, value, graph |
| Luminosity | lum | % (0 to 100) | p | gauge, value, graph |
| Luminosity | lum | Ratio | r | gauge, value, graph |
| Magnetometer | mag | Gauss | ga | gauge, value, graph |
| Magnetometer | mag | Tesla | tesla | gauge, value, graph |
| Motion | motion | Digital (0/1) | d | twostate |
| Nitrogen Dioxide | no2 | Parts per billion | ppb | gauge, value, graph |
| Ozone | o3 | Parts per million | ppm | gauge, value, graph |
| Particle Matter | pm | Micrograms | mg | gauge, value, graph |
| Power | pow | Watts | w | gauge, value, graph |
| Power | pow | Kilowatts | kw | gauge, value, graph |
| Proximity | prox | Centimeter | cm | gauge, value, graph |
| Proximity | prox | Meter | m | gauge, value, graph |
| Proximity | prox | Digital (0/1) | d | gauge, value, graph |
| Rain Level | rain_level | Centimeter | cm | gauge, value, graph |
| Rain Level | rain_level | Millimeter | mm | gauge, value, graph |
| Received signal strength indicator | rssi | dBm | dbm | gauge, value, graph |
| Relative Humidity | rel_hum | Percent (%) | p | gauge, value, graph |
| Relative Humidity | rel_hum | Ratio | r | gauge, value, graph |
| Resistance | res | Ohm | ohm | gauge, value, graph |
| Signal Noise Ratio | snr | Decibels | db | gauge, value, graph |
| Soil Moisture | soil_moist | Percent (%) | p | gauge, value, graph |
| Soil pH | soil_ph | Analog | null | gauge, value, graph |
| Soil Water Tension | soil_w_ten | Kilopascal | kpa | gauge, value, graph |
| Soil Water Tension | soil_w_ten | Pascal | pa | gauge, value, graph |
| Tank Level | tl | Analog | null | gauge, value, graph |
| Temperature | temp | Fahrenheit | f | gauge, value, graph |
| Temperature | temp | Celsius | c | gauge, value, graph |
| Temperature | temp | Kelvin | k | gauge, value, graph |
| Voltage | voltage | Volts | v | gauge, value, graph |
| Voltage | voltage | Millivolts | mv | gauge, value, graph |
| Wind Speed | wind_speed | Kilometer per hour | kmh | gauge, value, graph |
+------------------------------------+------------------+---------------------+------------+---------------------+
```