Project for getting started with temperature measurement using remote data transmission.

Measuring temperature is easy, but measuring temperature accurately is a challenge. The following points must be taken into account:

* How accurate is the measuring instrument, the temperature sensor? * How long is the sensor's response time to changes in temperature? * Influence of the sensor's temperature on the medium to be measured. * Influence of radiation, both internal and external, on the sensor and thus on the measurement result.

LoRa¹⁾ or LoRaWAN are suitable for remote data transmission. While LoRa is a radio standard, LoRaWAN is a network protocol. This technology is designed to transmit minimal amounts of data, such as from sensors, with minimal energy. There are both commercial networks and community-supported networks such as The Things Network. However, as the gateways (equivalent to routers for Wi-Fi) are operated by volunteers, they can be taken offline at any time. While there are often a large number of gateways available in urban areas, the network is sparser in rural areas. In order to have coverage for your own experiments and to ensure operation, we recommend operating your own gateway.

Gateways are available in a wide variety of designs and price ranges. One gateway that we operate is the Dragino Indoor LoRaWAN Gateway LPS8-868²⁾

In our experience, the radio range ³⁾ * the LoRIS-Base transmitter module, an experimental platform for LoRaWAN, LoRIS-BM-TRX1 (centre), ⁴⁾ * the LoRIS button cell ARR kit power module LR44 power supply, LoRIS-PM-BC. (Explanatory video AEQ-WEB channel LoRIS button cell: YouTube)

The individual modules are available from ELV

There are various options for the power supply:

It is possible to power the Loris Base directly via USB, as shown here in combination with the GPS module (video description on the AEQ-WEB channel on YouTube). Unfortunately, this does not work with all power banks; some with regulated output switch off due to the low power consumption.

This would be possible with the LoRIS-EnergyHarv Power Module Energy Harvesting, LoRIS-PM-EH. We have not tried this yet.

These options are available with the LoRIS button cell ARR kit power module LR44, LoRIS-PM-BC. We have tried this with button cells, but they are very sensitive to cold.

The image above shows the individual parts of the power supply that need to be soldered onto the circuit board.

- Decide which components to purchase. - Decide whether to purchase your own gateway or use gateways from the community. - Download the LoRIS Base Flasher Tool. - Download the firmware for the applications and flash it onto the LoRIS Base. - Set up an account with The Things Network. - Register the LoRIS Base (and gateway, if available) with The Things Network. - Solder the power supply module. - Plug the parts together and connect them to the power supply → test functionality. - Build housings for the individual modules; buttons should still be operable and LEDs should remain visible. - Set up a way to make the collected data accessible on the Internet.

* What should be measured and where? * Point measurements or repeated measurements? * How should the measurements be documented?

* The measurements should be taken by teams. The teams should exchange information about the measurements online, and all measurement data should be available to everyone. * The reliability of the data should be determined: how accurately can the measurement be estimated, what factors can influence the measurement? * Comparison with data measured by publicly accessible measuring stations. * In particular, it should be observed whether the temperature of the medium is actually being measured or whether it is the temperature of the radiation entering or leaving the sensor.

The experience gained will then be incorporated into the construction of a remote thermometer, which will then be used on board a gas balloon. This data will then also be available and critically evaluated.

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