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SAJAC is a smart jacket for caving that helps explorers to monitor environmental conditions and request help when needed using BLE and LoRa


Caves, which are quiet places and rarely passed by humans, often have extraordinary beauty. The beauty that is in it is very different from other natural landscapes. Caves often still keep a very pure natural beauty because of the lack of human activity in them. Caving is one of the exploration options to see this natural beauty.

Caving has become a hobby that has become increasingly popular in recent decades. Caving is sometimes done just for the pleasure of doing the activity or for physical exercise, still the beginning of exploration, or physics and biology also play an essential role. Caving has become even safer because of modern clothing and equipment.

Are all the equipment carried by explorers able to protect them 100% from the dangers? Certainly not. Many other dangers can threaten the safety of explorers in the cave. What are those things? Extreme temperatures, wet and humid air, low air pressure, poor air quality, and the potential for toxic gases. Moreover, the lack of a communication system sometimes worsened matters as explorers could not contact the outside world.


Related to this problem, I will develop the Sajac Project to help people who have a hobby of caving. Sajac Project is a smart monitoring system aims to observe environmental conditions in the caves. This system will provide information about how the environment around the users. This machine is equipped with machine learning to determine whether the environmental conditions and user friendly. At each checkpoint inside the cave, a transmitter will be connected directly to the guards outside. If the user gets a danger notification from his jacket, user can immediately ask for help at the nearest checkpoint using the transmitter, and the guards can immediately provide help as soon as possible.

How it Works?

This system uses Nicla Sense ME to condition determination. This tools can at one measure environmental quality around the user and send the result to Sajac Application in User’s smartphone. If the cave condition is not good enough to explore, there will be a notification alert in Nicla Sense ME or Users’s smartphone. This calculation is carried out using a model that previously applied on edge impulse platform with a high level of accuracy and small error rate.

At each checkpoint, there will be a transmitter that will directly inform the cave environmental conditions to the post guard. Considering there is no internet connection in the cave, this system will use LoRa communication system to transmit data from the checkpoint. This system is developed using XIAO ESP32C3 that is equipped with Grove Wio E5 from Seeed Studio. When the users arrives at the checkpoint, he only need to press “send” button after connecting to the transmitter at the post. The user also can determine whether he will return by him self or be picked up by the guards if the condition is impossible for him to continue his exploration.

The guards at the main post will receive data transmitted from the cave by using LoRa. At the front post, there is Wio Terminal Equipped with Grove Wio E5 to receive data from the transmitter inside the cave. Wio Terminal is effective to use in place with minimum power sources because it only needs 5 volt of power from powerbank.”

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