Setting a specific distance using Microwave proximity sensor

Hi there,
I am doing a project that entails a user to physically wear a microwave proximity sensor in the form of a bracelet in the hopes to detect when another person comes in contact of 2-3m. This would be used in our situation now of COVID-19, to allow people to accurately social distance.

My question is, is there a way to set a specific distance, say 0.5m-3m within a proximity sensor. As issue's are arising of the wearer being detected themselves and the cap being 3 metres distance.

Do any of you have any suggestions?

Something designed for ADAS might be plausible. You need proper antennas, it will be directional, a bracelet will not work, a badge-style might. Cost - no idea, expect expensive.

CV techniques might be worth investigating.

Small Lidar's are also possible. Again not cheap.

BTW most people are perfectly able to judge distance all by themselves, what problem are you addressing?

First of all, I must say that's the best hardware corona idea, I have heard so far.

Yeah instead of bracelet, you should design a badge and instead of IR Proximity sensor, try ultrasonic sensor. You can easily set the distance in arduino coding.

Moreover, add a small buzzer or vibrator for indication.

Hi

Microwaves are safe? I would use ultrasonic because is... slow.

My idea is to equip people (in my case workes in factory that usually work close to each other) in proximity sensors. I choose HC-SR4.

There is only one (I hope) problem I can't solve: transmitter is directional. Do you have any idea to make the ultrasonic noise enough strong in all directions (around transmitter)? "Enough" means to be heard by another sensor 2m far.

ps
I plan to use radio as a trigger. Every 800ms all sensors start transmit their signal (8 bit, so there will be 255 unique sensors to avoid echo, return 11111111 = obstacle).

I don't know if there is easier method (also does mine work?)

Hello

From my point of view it is an interesting subject.
Here in Belgium there is a company which has developed a bracelet which beeps when it is approached by another bracelet. I would like to know how it is working.

https://romware.com/covid-radius/

It would be interesting to understand how this can be done using Arduino.

Thanks
Mario

And here’s a working link

Seems its UWB technology, not cheap and not possible with arduino (is too slow).