Hello
Before I start, I am not an engineer and my question is about finding out what is possible or just how naive is my idea is.
Preamble :
I am a film maker who makes films on his own. Of all the technical challenges, my greatest is keeping people in focus. In film, this is called follow focus. There are some commercial solutions to solve this issue.
These solutions often go for thousands of dollars and I am sure that there is a reason for this. But many of these solutions are not adapted for one man band film makers like me.
Problem :
How to track objects to deduce their distance, using an Arduino?
Thoughts :
I started my thoughts supposing that the new smart phones with Lidar style scanning could map areas in real time and track objects, but I soon realised that was more science fiction than fact.
This system creates a wifi network that tracks actors etc using emitters attached to them and with a receiver attached to the camera, giving a very accurate positioning. I think this is called Wifi Positioning System (WPS)
Arduino has wifi and displays, so probably naively, I wondered if this was feasible project or just more science- fiction?
Any thoughts would most welcome in understanding what is possible .. or not ?
Many thanks
Naively, I was thinking of something based on wifi or bluetooth where a connection is made and distance can be calculated . I even wowndered why it could not be done via 2 mobile phones.
The Andra system was retailing at about 14K USD. I am not really sure who buys it but it does work well.
I have read that the Bluetooth 5.1 protocol has the possibility to calculate distance and direction to within a 1 cm and has a potential range of 50 metres
chlowden:
I have read that the Bluetooth 5.1 protocol has the possibility to calculate distance and direction to within a 1 cm and has a potential range of 50 metres
1cm resolution implies a timing resolution of better than 33 picoseconds.
Your mobile phone might get close, but don't hold your breath for a cheap microcontroller.
To be honest, I am starting to play at being an engineer, which I am not.
So, in short, I deduce from these exchanges that the tech I am pondering does not really currently exist .
chlowden:
So, in short, I deduce from these exchanges that the tech I am pondering does not really currently exist .
Maybe not yet.
That the capability to do this sort of location has been put into the Bluetooth 5.1 standard is good, but it does sound like it needs a fair bit of other stuff to provide the actual localisation and its the sort of stuff which does not sound 'low cost'
chlowden:
To be honest, I am starting to play at being an engineer, which I am not.
So, in short, I deduce from these exchanges that the tech I am pondering does not really currently exist .
SX1280 LoRa devices measure distance with a special packet exchange. Whilst its good for measuring long distances, the distance record is 89km, its not so good at short sub 100m distances. You can get distance variations of a few metres.
The main issue appears to be the stability of the fixed delays in the system as in the time it takes for the ranging packet to be received and the reply transmitted in the slave device. This fixed time needs to be subtracted from the total time to get the time of flight. A TCXO based SX1280 seems to help, but its doubtful you could get much better than 1m resolution.
