In the midst of the Corona Pandemic we are looking to develop a wearable sensor that when within approximately 2m of another (of the same type) of wearable sensor will log an event.

The ideal would be a low cost and very low power. It must work without line of sight since the sensor can be in your pocket etc. I've looked at all sorts of proximity sensors and none seem to be able to do the job.

My only solution I could come up with is a sub Ghz RF transceiver that polls (twice every second) and is in receive mode for the rest of the time and when a message is received an ACK is sent. The output power will be set very low (0 dbm) without an antenna so should get around 1.5 to 2.5 m range irrespective of a human body that is in between sender and receiver (If I go with my intuition).

Problem is that lowest RX current is around 7mA which means on a 1000mA battery will last less than a week.

Has any body done anything similar or have any advise on maybe another type of technology I can use?

Location is not important and it is most likely going to be indoor.

Any advise will be highly appreciated

 

Welcome to AAC!
If you are relying on signal strength to determine if two sensors A and B are within/outside the set range then there could be problems.
Suppose A and B are within the range but a signal-attenuating object C (e.g. metalwork, or someone without a sensor) comes between them. C will block/reduce the signal, so neither A nor B will then detect it.

 

Uh, google and apple are working on this using the devices we all carry in our pockets already. Which is a far better solution.

Bob

 

We don't all carry phones and many of us work in locations that are shielded for reasons related to internal security or building construction so a reliable phone independant human proximity system could be a useful product.

https://www.apple.com/newsroom/2020...rtner-on-covid-19-contact-tracing-technology/
https://www.eff.org/deeplinks/2020/04/challenge-proximity-apps-covid-19-contact-tracing

 

So, more of us will carryva bew device dedicated to logging proximity?

Neither approach will covet everyone, the cell phones will cover far more.

Bob

 

So, more of us will carryva bew device dedicated to logging proximity?

Neither approach will covet everyone, the cell phones will cover far more.

Bob

Sure, some will still need independant devices out of necessity, I still carry a pager (phone stays in the car usually) at work as cell and GPS service is minimal inside many metal clad office buildings where people spend long hours in close proximity.

Building Material / dB Loss
Metal -32 to -50
Tinted & Low-E Glass -24 to -40

 

Unfortunately, the trust factor is likely to stop this from ever becoming widespread. There is good reason not to trust google to refrain from capitalizing on this info. Apple has a better record on privacy, but I still have limited use of my location info to specific apps on my iphone, and only when open.

Bob

 

Hi

I actually stumbled across this.

I company in New Zealand developed a device very similar to what we intend to develop.

They use BLE and the device is the size of a credit card. It states that battery can last 12 months. How could this be possible? can you continuously scan with BLE and get 12 months on a battery the size of a credit card, or am I missing something here?

Here is the news article: https://www.stuff.co.nz/national/he...nd-considering-100m-contact-tracing-covidcard

 

Hi

I actually stumbled across this.

I company in New Zealand developed a device very similar to what we intend to develop.

They use BLE and the device is the size of a credit card. It states that battery can last 12 months. How could this be possible? can you continuously scan with BLE and get 12 months on a battery the size of a credit card, or am I missing something here?

Here is the news article: https://www.stuff.co.nz/national/he...nd-considering-100m-contact-tracing-covidcard

Continuously scan doesn't mean Continuous operation. You need a ping (BLE RX/TX sequence) rate (x times per second) appropriate for the target you are tracking. (usually a human walking) Between pings the device sleeps with current usage in the uA range usually. The average power usage would be low.

 

One such local guy here at us in the food store without of any proximity logger got eye the certain other guy is simply tearing in onto him at the cash. So he invited to step him back twice and when he not listened just hit him a teeth. Now the police stands interests of "citizen on hurry" but guy who more than logically defended own life from virus infected ter-in evildoer now sits in prizon for 5 years of "failed trial of murder". For my imho, proximity sensor is aimless spend of time and money. Everyone have an eyes and all may be decided by SIZE of one`s gun.

 

Social distancing warrior.

 

In the midst of the Corona Pandemic we are looking to develop a wearable sensor that when within approximately 2m of another (of the same type) of wearable sensor will log an event.

The ideal would be a low cost and very low power. It must work without line of sight since the sensor can be in your pocket etc. I've looked at all sorts of proximity sensors and none seem to be able to do the job.

My only solution I could come up with is a sub Ghz RF transceiver that polls (twice every second) and is in receive mode for the rest of the time and when a message is received an ACK is sent. The output power will be set very low (0 dbm) without an antenna so should get around 1.5 to 2.5 m range irrespective of a human body that is in between sender and receiver (If I go with my intuition).

Problem is that lowest RX current is around 7mA which means on a 1000mA battery will last less than a week.

Has any body done anything similar or have any advise on maybe another type of technology I can use?

Location is not important and it is most likely going to be indoor.

Any advise will be highly appreciated

Nice idea however;

very very difficult !!

Radio signals are not useful. Separate two persons one ill by a window/wall. (distance between heads 1mtr )
Result false detection
GPS: not accurate and will not work in buildings or other closed environments.
Ultrasonic device accuracy.
Number of measurements, speed of logging and more.

The real humane problem:
How do you know that person X is ill?
Is person X willing to indicate that by entering in the system Yes I am ill?

Question: when a ill person is detected by your system what happens then?
loud signal, vibrating unit?
Or will the ill person save all Id of the people within the range specified?

How to go further? Inform the health authorities and transfer the file?
What type of information should carry the ID?
Next question: Is the so collected information useful to other parties and can this harm your freedom for now and in the future ?

Costs?

It's not simple at all.
A real problem. A thing hardly visible by microscope is disabling the world from normal operation.

This is a WAR!!!! All countries should work together no political shit. Lets destroy this dammed virus together.

Picbuster

 

This is a WAR!!!! All countries should work together no political s&%t. Lets destroy this dammed virus together.

Picbuster

A WAR?

Let's get serious, this is not a war. A war mentality is the wrong strategy here because that assumes we can win in a bare knuckle contest with nature. It's a race for a lower death rate truce until the next viral infection or natural calamity takes out some small or large part of our species.