Car temp sensor with LoRaWAN remote display

Projects Programming
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Last summer I was faced with following dilemma: Situation: Travel group was my wife and me & 2 dogs with car. Traveling in foreign country, my wife did not speak the language. My wife needed urgent hospital visit. Dogs not allowed inside hospital, so only option was to leave them in the car on hospital parking. Dilemma: One major concern was temperature inside car & dog wellbeing, other important concern was me being absent at time doc with diagnosis would turn up. Short summary: Everything ended well, this involved trusting a complete stranger to look after our dogs. I did a lot of thinking how technology could come to help to manage such a situation better -if needed- in the future. Hopefully not, but it's better to be prepared.
Technological idea I have in mind would be
a) Hardware: A Dragino LHT65N LoRaWAN temp sensor(or equivalent) + transmitter in the car, point-to-point LoRaWAN connection to a WIO + WIO battery + WIO terminal chassis with LoRa-E5. (So 3 WIO modules stacked together). Total HW cost would be about €150.
b) Software: Transmitter is configured through AT commands.
Receiver displaying on the WIO display: Car temp + Seconds ago last temp update received.
(This "seconds ago" would give assurance that connection is working and temperature data received is reliable).
No communication WIO ==> sensor.
The 1-2 km LoRaWAN range would be adequate for most situations.
Project question:

  • I didn't find any commercial solution that does this. If I would find one, I assume the important-for-me "seconds since last update" would be absent. Correct?
  • Any compatibility issues with the hardware proposed? Would it do the job?
  • What are the problems to be expected with this point-to-point LoRaWAN connection? How would "peering" work?
  • I've worked with WIO before. How difficult would it be to get the LoRaWAN part of the WIO software to work up to the point where 2 variables contain temperature & time received?
    Thanks in advance for any insight.
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Technically:
I would probably use a smaller receiver device.
Some of these ESP32 Boards with LoraWan + small OLED. And add an acoustic alarm when temp is to high or connection timed out.

Dogs:
The car is no place to keep dogs unattended - under no circumstances. End of story.

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Are you using LoRaWAN in the usual context ?

LoRaWAN is normally used for node to Gateway communications, where communities install the Gateways.

You would not normally use LoRaWAN for an alarm type application, since the node to Gateway comms is in no way guaranteed.

Maybe use LoRaWAN as a backup, but your application seems ideal for a GSM type warning, mobile phone coverage is mostly heaps better than LoRaWAN.

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LoRaWAN requires access to a local gateway which may not be available in many locations
as @srnet suggests GSM appears to a be a suitable technology, e.g. a MKR GSM 1400

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Or use a simple to setup LoRa point to point link as the primary alarm, and if there is no response from the remote receiver, send an alert over GSM ?

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Thanks for all answers!
This enabled additional research, GSM indeed seems to be the preferred choice for setting up communication for this specific case. The MKR GSM 1400 (although end-of-life) seems the preferred choice for this application: It seems good at SMSing and example code is available. Since this forum is not a forum around dogs, I won't respond to that specific remark in one answer, I just would like to point out that many other items (like vinyl records, medication, refrigerated stuff,....) could also benefit from the type of monitoring that I'm looking for.

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