this kind of optic fiber is probably only plastic so for a full DIY , you can use also fishing wire with a big power led or an old chistmass tree optic fiber lighted.....
Advantage of this sensor is fast and easy installing by the non qualified personal. The sensor is designed for large agriculture facility with many greenhouses where is needed to be controlled temperature and humidity, the atmospheric pressure is for control the motor of air inlet and outlet. With help of the sensor installed outside the greenhouse provide information about positive/negative pressure inside the greenhouse.
Finlay the software read accurate temp/humid value of the Si7021, and only atmospheric pressure of BMP180, the temperature sensor inside the BMP180 is used only by the sensor itself to provide accurate atmospheric pressure measurements.
The sensor can be used also for home automation, and drone applications where is needed correction of the UAV barometric sensor compared to the ground barometric sensor, also humidity measurement can help the pilot to calculate more accurate flying time.
@NeverDie Thx for appreciating the work done. There will also be an open source part in the future. When and how extensive the open source part will be, remains to be seen. The release of certain information (block diagram, ..., in this post) is related to those open source parts.
There are some OBD solutions, however most of them (in my experience) give back low frequency data put by the car manufacturer on the OBD-bus (CAN, ...). Therefore transients evolving directly from the battery could only be recorded if the manufacturer sends those data accordingly on the bus. Due to the small bandwidth(also because of other car data that have to be sent, ...), such battery data are sent more often once per second or less. Fast battery events (i.e. cranking events, ...) are therefore imperceptible. Unless the manufacturer processes the fast events and then sends them (once per second or less), which is very unlikely if the manufacturer does not market this feature itself. Third parties devices for high frequency sensing costs several hundreds dollars.
In my experience, important battery states (especially the fast ones) are recorded by measuring and processing corresponding data directly on the battery.
I agree with you about the limits related to the communication over Bluetooth. But i think Bluetooth 5.0 will improve a lot. However, WiFi will always remain an important option due to the high data throughput. The combination of both (BLE & WiFi), especially with regard to energy consumption, will gain in importance.
My next issue is the humidity seems to be off. It has read as high as 115% humidity. Is this normal or should I be considering a correction? If so, how would I enter a correction. Its a little odd considering it states that the accuracy is much tighter than that.