Module/Hygrosens TEMOD-I2C-R1
Overview
The Hygrosens TEMOD-I2C-R1 is a converter board to measure temperature by a PT1000 sensor and output the data through an I2C interface. It is the standard fast temperature sensor for the SUMO.
There are -R2 (-32°C .. +224°C) and -R3 (-32°C .. +480°C) modules available that have a higher maximum temperature but lower resolution.
| Module name | meteo/temp_temod |
| Sensor type | temperature |
| Range | -32°C .. +96°C |
| Resolution | (1/256)°C |
| Refresh rate | 8Hz |
| I2C address | 0xF0 |
Hardware
The data sheet mentions a minimum supply voltage of 6V but it seems to work ok with 5V. The board does have a 5V I2C interface. It can not be directly interfaced to the Paparazzi autpilot 3.3V I2C interfaces. A level shifting adapter board is needed. The PT1000 sensor is not included with the module. The Heraeus M222 sensor is used as it has a small mass.
Module supplier: Conrad
Level shifter supplier: Sparkfun
PT1000 sensor supplier: Conrad
Wiring
| Autopilot I2C pin | Autopilot I2C | Level Shifter | TEMOD-I2C-R1 | TEMOD-I2C-R1 pin |
| 1 | GND | LV_GND | ||
| 2 | +5V | HV_HV | Vdd | 1 |
| 3 | +3.3V | LV_LV | ||
| 4 | SDA | LV_TXI_Chan1 | ||
| 5 | SCL | LV_TXI_Chan2 | ||
| HV_GND | GND | 2 | ||
| HV_TXO_Chan1 | SDA | 3 | ||
| HV_TXO_Chan2 | SCL | 4 |
Usage
To use the temperature sensor add the module to your airframe file.
| File: conf/airframes/myplane.xml |
<modules>
<load name="temp_temod.xml"/>
</modules>
|
The standard module is the TEMOD-I2C-R1 with the highest resolution. The -R2/-R3 type can be configured.
| File: conf/airframes/myplane.xml |
<modules>
<load name="temp_temod.xml"/>
<configure name="TEMOD_TYPE" value="TEMOD_I2C_R2"/>
</load>
</modules>
|
Result message
The raw data (itemp) and the converted result (temp) is written to the log file. The message is automatically sent when new data is received, it does not have to be added to the telemetry file.
| File: conf/messages.xml |
<message name="TMP_STATUS" id="86">
<field name="itemp" type="uint16"/>
<field name="temp" type="float" unit="deg_celsius" format="%.2f"/>
</message>
|
Sample log file line
5.980 123 TMP_STATUS 13486 20.68
NOTES
The location of the sensor on the aircraft does matter. There are various papers that analyze the best location. So far we have installed them within tubes (to protect from sunlight/heating) on the wings. That might not be the optimum place.