In my realworld experience (and hologram’s) each message sent to the hologram cloud socket uses a minimum of ~500 bytes. Check out the discussion: Data Usage and more
Things to consider beyond what @Maiky listed are:
- DNS lookup (going from url to ip address) possibly also requring a TCP connection
- TCP handshake (there are multiple packets that have to go back and forth between server and client to establish a tcp connection)
- TCP ACK packet (probably only one in your case as payload is so small)
- Any re-transmission due to dropped packet(s)
So in reality I would expect your monthly cost to be
(500 bytes overhead + 100 bytes payload) * 8640 updates / month = ~5.2 MB
The only way to reduce this would be to:
- “phone home” less often, like every 30 minutes to get closer to your initial 0.86MB estimte
- use UDP to your own server and accept the reduced QOS UDP gives over TCP
- use a persistent TCP connection such as MQTT. This means you only pay the 500byte pentalty once. You will have to look into a 3rd party (or your own) MQTT service as I dont think Hologram supports this at the moment.
Note once you have higher volume, look in to Hologram’s data pooling to significantly reduce the cost per MB. This is a good option if you usage is somewhat predictable. May not be for luggage tracking if its for travelers as I wont turn on my luggage tracker unless I am traveling.
EDIT: I should note @Maiky linked to the same Hologram blog that is in the other forum that has the table showing overhead. You’ll notice the Billed Byte Size is 496 bytes greater than the Payload Bytes size for the Cloud/Socket connection method (which is what you should be using).
