Hello,
First off - I apologize if there is an obvious answer - I have looked through the product page and through the forum briefly but haven't found an answer to this question.
My goal with the CC2541 sensortag kit is to have multiple deployed in sort of an "easter egg hunt", and people will be looking for them in a sort of geo-caching type hunt. They will be passing by quickly once they have found them and look for the next one. It's a point-to-point race essentially - so I need a quick verification, and acceptable proximity distance resolution.
I would like the phone to record it's distance from the tag and record distances while near the sensor. My functionality that I need and cannot find in an obvious way is one where I need proximity data. I need to record within a 20 foot radius (at MAX) and preferably between 2 feet and 10 feet, and have some resolution in between there.
Also - if the person is approaching the sensor and passes by quickly - is there a minimum time needed before there is a connection between the phone and BLE device? I essentially need a confirmed connection within 1 second or less of being in range of this kit.
I am wondering what attributes I will have to monitor to get this data - and if there is already a library made to extract this based on attributes such as signal strength.
I guess the only lead I have to a possible answer to this is using the signal strength (RSSI) value as it is definitely indicative of the proximity of the sensor to the phone - but it can very greatly with a change in the medium inbetween the two (such as if the phone is in one's pocket, or behind something).
Perhaps I could use the RSSI signal strength and the data sheet which should have a graph of signal properties to formulate a distance formula?
Thanks - hopefully my question is not too vague!