Low/zero cost IoT data receiver + graphing service

[hamster_nz]

I'm looking for something to receive data from a few IoT temperature sensors I'm building, just to timestamp and hold the values for later review.

I'm currently logging data on a desktop PC over https, but would prefer to not have to leave the PC on all the time.

The other option I am deciding between is to use a Raspberry Pi, but that is just one more thing to look after...

[Mr.B]

I am currently using ThingSpeak for what sounds like a similar task as yours.
https://thingspeak.com/

No cost as long as your logging is not quicker than once every 15 seconds.
Very easy to code for.
API documentation is not too bad.

[hamster_nz]

I am currently using ThingSpeak for what sounds like a similar task as yours.
https://thingspeak.com/

No cost as long as your logging is not quicker than once every 15 seconds.
Very easy to code for.
API documentation is not too bad.

Thanks - I was looking at them as an option but was not going to commit the (now minimal) development time until I got a recommendation.

It is nowworking nicely....

[Mr.B]

Good stuff.

I am using the JSON option for 36 IoT field sensors on 36 different channels at ThingSpeak and it has been working very well for 6 months.
Make sure you code for a 'failure to connect'...
It happens about once a week randomly for my devices, the ThingSpeak server does not respond.
I just store the timestamped values and try again at the next comms cycle - 15 minutes in my case.

[hamster_nz]

Good stuff.

I am using the JSON option for 36 IoT field sensors on 36 different channels at ThingSpeak and it has been working very well for 6 months.
Make sure you code for a 'failure to connect'...
It happens about once a week randomly for my devices, the ThingSpeak server does not respond.
I just store the timestamped values and try again at the next comms cycle - 15 minutes in my case.

Thanks for the heads up.

For battery life I am going to deep sleep between reading, so might look at using some bytes in the RTC's SRAM to hold samples if connect fails, as RAM contents gets nuked ...

[Mr.B]

For battery life I am going to deep sleep between reading...

My devices are based on ESP8266, so the deep sleep requires a boot.
I am using the cheapest Cypress FRAM to store data between boot due to the write longevity.
Works very well.
Cheers...

[mac.6]

try to find a cloud provider that use Thingsboard , this way you can prototype on your own network, then move it to/from cloud without relying on specific vendor.

[Mr.B]

Thank you. That looks very promising.

[hamster_nz]

The second sensor is out in the garden, running off 3xAA.

Without any board mods (e.g. removing the USB interface's  CH340) it is 0.8mA when asleep, and about 120mA when on the Wifi, as Wifi is active for 10 seconds every 10 minutes, the average draw is about 1.2mA.

Should get all of summer out of a set of batteries...

If interested, data is at https://thingspeak.com/channels/357477 and project code is at https://github.com/hamsternz/thingspeak-esp32-dht11