Dual Digital Temperature Probes 

Temperature Display
Temperature Display

Can be used with: 

If connected, the temperature measured by these probes are displayed as seem at right. Either one or two probes may be connected on a common 3-wire connection cable. The button position that a given probe reports in is determined by its built-in address. To find which is which plug them both in and warm one of them in your hand. The order of addressing cannot be changed. The probes have a measuring range of -55 C to 125 C. 

What Use Are They?

Camping fridges that work on the Absorption Method (the type that can run on gas) are sensitive to environmental temperature. Their performance depends greatly on the effectiveness of the cooling radiator located behind the fridge cabinet, which is directly affected by the ambient temperature and the airflow in that area. The warmer it gets behind the fridge the more gas needs to be burned to keep the fridge working, which leads to even higher temperatures around the radiator.

In most cases the fridge will stop working ( i.e. the freezer will not reach target temperature) once the radiator reaches 35°C. Often the ventilation ducts that the caravan builder provides are inadequate for the large volume of air that needs to circulate behind the fridge to keep things cool enough to preserve your foodstuffs. 

Many owners resort to fitting 12VDC computer fans (known as muffin fans) to augment airflow through the ventilation grilles provided by the caravan maker. These temperature probes allow you to monitor the temperature both inside and behind the fridge and alert you to a potential problem before major damage is done.

Overheat Indication

A maximum temperature threshold level can be established for both heat probes anywhere between -55°C and 125°C. Any time the temperature rises above this threshold level the background of the temperature display will turn red and a gong will sound in the phone. Once the temperature drops below the threshold level the background will revert to grey.

Setting the Threshold

To adjust the temperature threshold tap the relevant temperature display button once and then within 3 seconds double tap the Caravan Pilot title. This may be easier with the phone lying on its back. A slider control will appear as shown at right. Move the slide control until the desired threshold is displayed. To Save tap the Caravan Pilot title once more.

The threshold setting may be quickly checked by tapping the Temp button once. The calibrated level will show for a few seconds, after which the button will revert to its normal display.


The temperature probes are addressable digital devices that are connected through a common input - a 3,5mm stereo plug. Detecting the presence of the probes is a lengthy and complex process since each probe has a unique address that must be discovered by the controller at every power-up. Only those probes detected at program start (power on) will be interrogated during the running of the controller's firmware program.

Therefore if any probe is added after power on the controlled should be restarted by a brief power off and on again.


The probes as supplied are not sufficiently well sealed to allow immersion in any liquid. If total immersion is contemplated additional sealing should be applied to ensure no liquid can penetrate the housing at the cable entry point.

Sensor Initialisation Command

The temperature sensors are addressable electronic devices that are discovered by the controller at program start. If any device is plugged in or out after controller start-up it will not be detected until the controller firmware is restarted by a power-down, or a Sensor Initialisation command is issued by the mobile phone app. To send such a command double tap the left hand (Temp 1) temperature button. This will command the controller to rescan for connected temperature sensors.