Low power proximity sensor

[tonyrhill]

I am finalising my project to open home security gates using mobile phone. However thinking ahead I have researched using ANPR (Automatic Number Plate recognition) This would be useful for friends and relatives arriving. However when I look at projects that have used a PI it would seem to me they would take too long to read and computing power/speed would not be good enough.

So I am thinking of a low power (button battery powered) type proximity device which could be put in the car or indeed pocket and it would open gates on approach. It would need a range of say 3-4metres.

Has anyone had any experience on these and recommend a type to use, if there is anything available.

[Douglas6]

Battery powered Bluetooth beacons are popular now, and can be purchased for $10 - $15 or less. The RadBeacon Dot is one example.

[OutoftheBOTS]

I have a done a few projects with RPi3 and OpenCV for computer vision projects and certainly don't have problems with image processing speeds.

Here is a youtube vide that I found with a quick google running ANPR on RPi with OpenCV and you can see the it picks up all of the number plates from a video stream whith panning camera in a car park see https://www.youtube.com/watch?v=d34II6pAR1Q

[tonyrhill]

Thanks for both replies. I will look at beacons and ANPR when I can get some time