Seeking WiFi-based personal alert device

[Involute]

My wife and I just installed a small gym in our backyard. It's occurred to us that if either of us had an accident out there, there would be no way for the other to know. I've been thinking about how to deal with this issue, assuming the victim were still capable of minimal movement, but not able to get to their phone. There are personal alert systems that consist of a button on a bracelet or necklace that you can push, but they rely on a subscription service where someone on the other end then notifies someone else. It seems to me it would be simpler, faster, and cheaper to simply notify a designated recipient directly via SMS. Since the gym is covered by our WiFi network, the device wouldn't even need a cellphone subscription. Has anyone seen such a device?

It sounds like it would be pretty simple to implement with an ESP configured via its own web page, so it wouldn't even need a display. I've read a lot about ESPs, but I haven't developed for them, so I don't know if there are SMS libraries. Are there? Of course, someone would get a fee if I used SMS, but I have to believe it would be way less expensive than one of the aforementioned services.

Any comments or criticisms appreciated.

[tommeyers]

There exist alert buttons like you describe. I have purchased them in the past. And they xan activate a relay (sold as a pair)

Use the transmitter to activate the relay; detect it with an esp. Use IFTTT free service to connect devices. Run something on your phones to receive alerts. Or activate an alarm sound, or ...

Tom Meyers

[Agree007]

Use a small esp32 in Deep sleep, with a battery and button The esp32 wakes up, when the button is pushed and send an email, or TCP/UDP message to other esp32 ( Places within WiFi Range) which the flash red light, activate a buzzer, promt message on a max7219 display et.

[WiFive]

There are also Bluetooth buttons or "panic buttons" that you could keep in a pocket or on a necklace or bracelet and they would trigger the nearby phone to send a message which would have redundant wifi and cellular network available. Possibly more reliable, smaller, and commercially available.

[Involute]

There exist alert buttons like you describe. I have purchased them in the past. And they xan activate a relay (sold as a pair)

Thanks, Tom, but the button isn’t the tricky part; it’s the SMS. You jogged my memory of those wireless fobs, however (like these: https://www.adafruit.com/?q=315mhz&sort=BestMatch), which I’ve used before, too, and that sent me down a rabbit hole leading to flic (https://flic.io/). With IFTTT/Zapier/Twilio that may solve my problem.

[Involute]

There are also Bluetooth buttons or "panic buttons" that you could keep in a pocket or on a necklace or bracelet and they would trigger the nearby phone to send a message which would have redundant wifi and cellular network available. Possibly more reliable, smaller, and commercially available.

Yup. See my reply to Tom.