I’m planning to use the sensor in a location without a constant Wi-Fi connection. I can provide internet access via a mobile hotspot from my phone, but only once or twice a week, and only for a few hours at a time.
My questions are:
Will the sensor still function without being connected to the internet?
Does it only operate while connected?
Will it store measurement data locally when offline?
Can I retrieve this stored data whenever I connect it to my phone’s hotspot?
Welcome!
1-No because it will stop to produce its own network after 10 min. You won’t be able to see the measurements if you have no screen on the sensor.
2-Yes. It is the only way to send the data to the SC API and to see the data through the router.
3-No.
4-No. And we can’t guarantee that it works through a phone hotspot. I have already succeeded but most of the time it does not work.
Could you get access to a LoRaWAN network ? But in this case you need another kind of board.
NB-Iot could also be a solution but it is complicated without programming skills. Feel free to contact me for libraries etc.
You could also collect data on a SD card but you won’t be able to send the data to SC.
Something I’ve been playing with lately: meshtastic, it’s a LoRa network/protocol. In some ways a bit similar to TheThingsNetwork/LoRaWAN, but not as sophisticated yet. LoRaWAN is structured like a star-network, with a couple of well-placed gateways serving potentially hundreds of nodes. Meshtastic is more like a peer-to-peer mesh network, each node can als act as ‘gateway’ to repeat a message to the next node. A fraction of meshtastic nodes is also connected to the internet. LoRaWAN typically uses 8 frequencies and several different modulation speeds. Meshtastic can use different frequencies too and different modulation speeds, but typically (in EU at least), the de-facto standard is SF11 modulation at just one channel/frequency at 869.525 MHz.
So it would be possible to build a sensor node that sends data towards meshtastic and if the message reaches (within 3 hops typically) a node that has MQTT connectivity, the message is forwarded to an MQTT server. A backend-process can then pick up that message from MQTT and forward it further to sensor.community.
Unlike TheThingsNetwork, the current meshtastic infrastructure is a bit ad-hoc, there is a kind of “central” MQTT server that is used by most internet-connected meshtastic nodes in the netherlands, but I don’t know about the situation in germany or in other european countries.
We have develop based on SC firmware our own firmware version connected to BK-SIM7000 PCB board (SIM7000 Development Board) => Multi-Band LTE module which supports LTE CAT-M1(eMTC) and NB-IoT based on 4G.
Is now in test fase:
Has been working in the field for 3 months now without any problems.