Our goal is to keep every child K-12 safe and accounted for during school outings. We do this with our next generation software, Never Lost.
There are many solutions to this problem that are solved with other technologies like blue tooth but those always come with inherit downsides, mostly smaller range and limited clients. Never lost uses its own wifi to connect that is capable of connecting to many clients and with more future development we would be researching in how we could used wifi tracking techniques to get a rough position of clients
It keeps all the clients connected to it (the children on a field trip) within a specified range of the host (the teacher watching over them) in order to prevent them from getting lost or potentially kidnapped. If one of the clients get out of range an alert is sent to the teacher with the clients name and an alert is sent to the client to start making noise. This alert can only be turned off from the host app.
We used a raspberry pi as an access point then created an express server on the rpi that would ping the clients connected every 10 seconds and measure the time it takes to get a response. If it takes too long it will send out alerts. We also built an android app for the host and clients to send and receive pings/alerts.
We were plagued with hardware issues. At first we had a raspberry pi 4 but there was no hardware in the building to allow us to interface with it and get a display signal out so it became useless and we had to try and get a raspberry pi 3. Although we couldn't get a raspberry pi 3 because the hardware table was out of them. This left us with a raspberry pi 2 and because there is no integrated wifi in a rpi2 we had to also use a wifi dongle. By this point its Saturday afternoon in the hackathon already and we're on limited time. Then while trying to set up software we ran into more hardware problems and found out the wifi dongle has its own special drivers and software we need to use in order to use the software thats meant to allow the raspberry pi to become and access point. Then we needed to install more software in order to build kernels so that we could be able to build the software for the dongle. Our final hardware roadblock was the scripts provided my the manufacturer was detecting our OS as Arch Linux based rather than Debian Based and we didn't know how to change that without editing the scripts.
We were able to come up with our idea which we think still has potential with the correct hardware and more time. We also were able to learn how to make android apps in this small amount of time. Hardware wise we were also able to find a wifi signal from our devices, but connecting crashed our pi. Also made a website advertising with React.
We also learned a lot about what hardware not to use for this and a lot about wlan0 eth0 and br0 networking connects. We also learned how to make android apps. Also a lot about different types of hardware that are wifi enabled and would be better to use for this if available.
We will probably figure out how to get the correct hardware and see if we have any more luck with creating a working access point with an rpi4 that we can actually get a display out of