Hi, I am trying to make a proof of concept, in a very short time frame.
Requirement is to track people issued with some kind of tag and to show the people in each room, on each floor of a building. Fairly straight forward really.
As the budget is very small, long range RFID is out due to the cost of readers that can read 5mtrs.
I am thinking the pet tags that are on ebay for cats dogs and kids for $5 might be acceptable as I hear they are BLE devices with a range of 20-30 mtrs.
These can be used with your smart phone to track pussy. So if an android device can track them, it cant be rocket science.
I guess they are reading the mac address or BT ID
I envision a “node” being a device with BLE and WIFI, possibly battery powered but not essential.
When a tag is in range, the node will send the ID via wifi to the network, where a server will take these pings and record them. This part (the server) is easy for us. I just need help with the nodes.
My first question is
Does anyone know how the tags work, and a suitable low cost device to read them.
Eg. Adafruit nRF52840 or 32u4 bluefruit LE or Particle Argon
My second question is
Is anyone skilled with these devices and would like some work to develop this?
Sounds like a cool project and reminds me of some of the Final Year Projects my university cohort was working on, not a trivial problem by any means.
My knowledge is quite limited with BLE myself so I’m not sure exactly how you would go about building this but I’d agree that RFID is a no-go and not worth pursuing further for the detection ranges you are needing.
Do you have a link you can share to the eBay tags you mentioned so we can try and find some specs on them?
If you are needing these built in a short time frame you’d be best to get a hardware accelerator or engineering consultancy involved. We can help with free advice to get you through some of the hurdles of building your own project, but we don’t provide paid engineering services. We recommend SAPHI as a local team with good results in the past.
For the “node” I would be inclined to use a Raspberry Pi Zero W since along with python they are great for rapid protyping. At 0.5W they could be battery operated (just).
On my pi just did a scan for BLE devices
sudo hcitool lescan
and it quickly picked up my keys tag along with a heap of other devices in my office.
F9:A3:C8:81:09:E4 Sense
Other things you would need to consider…
You need a metal case to store tags not in use.
You need a label maker to number each tag.
You need a script to scan the MAC address and name of each tag into a database with its number (which could be on a Raspberry Pi 4)
You need a script to add/remove the person attached to the tag.
In operation the Pi Zero W would BLE scan say every minute and send the list through to the Pi 4. If the MAC is in the database it can add the room.
The major risk I see is that in a room full of people each with your tag, their own tag, mobile phone, laptop etc there could be huge number of BLE devices and the scan could take ages or perhaps not complete. Another risk is if someone is walking down a corridor they could get scanned by two or more nodes so you may need a “transit” room.
You could offer a “security” service for people who have tags in their briefcases planted by their spouses!
Keep thinking of features you could add on to the product.
At the exit you could have a node scanning for people who have not returned their tag. It could sound an alarm, flash a light and annunciate “Please return your tag”. A robot could run out and bite their leg.
Once they have left the building, GPS turns on so you could track them.
